Articles | Volume 16, issue 7
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Use of lidar aerosol extinction and backscatter coefficients to estimate cloud condensation nuclei (CCN) concentrations in the southeast Atlantic
School of Meteorology, University of Oklahoma, Norman, OK 73072, United States
School of Meteorology, University of Oklahoma, Norman, OK 73072, United States
School of Meteorology, University of Oklahoma, Norman, OK 73072, United States
Sharon P. Burton
NASA Langley Research Center, Hampton, VA 23666, United States
NASA Goddard Institute for Space Studies, New York, NY 10025, United States
School of Meteorology, University of Oklahoma, Norman, OK 73072, United States
Richard A. Ferrare
NASA Langley Research Center, Hampton, VA 23666, United States
Chris A. Hostetler
NASA Langley Research Center, Hampton, VA 23666, United States
Pablo E. Saide
Department of Atmospheric and Oceanic Sciences, University of California – Los Angeles, Los Angeles, CA 90095, United States
Institute of the Environment and Sustainability, University of California – Los Angeles, Los Angeles, CA 90095, United States
Department of Atmospheric and Oceanic Sciences, University of California – Los Angeles, Los Angeles, CA 90095, United States
Bay Area Environmental Research Institute, Moffett Field, CA 94035, United States
NASA Langley Research Center, Hampton, VA 23666, United States
School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332, United States
Department of Atmospheric Sciences, University of Miami, Miami, FL 33146, United States
Department of Chemistry and Biochemistry, Mount Allison University, Sackville, New Brunswick, E4L 1E2, Canada
State Agency for Nature, Environment and Consumer Protection North Rhine-Westphalia, 45659 Recklinghausen, Germany
Institute for Chemical Engineering Sciences, Foundation for Research and Technology, Hellas, 26504 Patras, Greece
School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique fédérale de Lausanne, 1015 Lausanne, Switzerland
No articles found.
Neranga K. Hannadige, Peng-Wang Zhai, Meng Gao, Yongxiang Hu, P. Jeremy Werdell, Kirk Knobelspiesse, and Brian Cairns
Atmos. Meas. Tech., 16, 5749–5770,Short summary
We evaluated the impact of three ocean optical models with different numbers of free parameters on the performance of an aerosol and ocean color remote sensing algorithm using the multi-angle polarimeter (MAP) measurements. It was demonstrated that the three- and seven-parameter bio-optical models can be used to accurately represent both open and coastal waters, whereas the one-parameter model has smaller retrieval uncertainty over open water.
Kristina Pistone, Eric M. Wilcox, Paquita Zuidema, Marco Giordano, James Podolske, Samuel E. LeBlanc, Meloë Kacenelenbogen, Steven G. Howell, and Steffen Freitag
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).Short summary
The springtime southeast Atlantic atmosphere contains lots of smoke from continental fires. This smoke also contains water vapor; more smoke means more humidity. We use aircraft observations and models to describe how these values change through the season and over the region. We then sort the atmosphere into different profile types, by vertical structure and amount of smoke and humidity. Since they both absorb solar energy, our work helps to better quantify the heating effects in this region.
Ghislain Motos, Gabriel Freitas, Paraskevi Georgakaki, Jörg Wieder, Guangyu Li, Wenche Aas, Chris Lunder, Radovan Krejci, Julie Thérèse Pasquier, Jan Henneberger, Robert Oscar David, Christoph Ritter, Claudia Mohr, Paul Zieger, and Athanasios Nenes
Atmos. Chem. Phys., 23, 13941–13956,Short summary
Low-altitude clouds play a key role in regulating the climate of the Arctic, a region that suffers from climate change more than any other on the planet. We gathered meteorological and aerosol physical and chemical data over a year and utilized them for a parameterization that help us unravel the factors driving and limiting the efficiency of cloud droplet formation. We then linked this information to the sources of aerosol found during each season and to processes of cloud glaciation.
Calvin Howes, Pablo E. Saide, Hugh Coe, Amie Dobracki, Steffen Freitag, Jim M. Haywood, Steven G. Howell, Siddhant Gupta, Janek Uin, Mary Kacarab, Chongai Kuang, L. Ruby Leung, Athanasios Nenes, Greg M. McFarquhar, James Podolske, Jens Redemann, Arthur J. Sedlacek, Kenneth L. Thornhill, Jenny P. S. Wong, Robert Wood, Huihui Wu, Yang Zhang, Jianhao Zhang, and Paquita Zuidema
Atmos. Chem. Phys., 23, 13911–13940,Short summary
To better understand smoke properties and its interactions with clouds, we compare the WRF-CAM5 model with observations from ORACLES, CLARIFY, and LASIC field campaigns in the southeastern Atlantic in August 2017. The model transports and mixes smoke well but does not fully capture some important processes. These include smoke chemical and physical aging over 4–12 days, smoke removal by rain, sulfate particle formation, aerosol activation into cloud droplets, and boundary layer turbulence.
Stylianos Kakavas, Spyros N. Pandis, and Athanasios Nenes
Atmos. Chem. Phys., 23, 13555–13564,Short summary
Water uptake from organic species in aerosol can affect the partitioning of semi-volatile inorganic compounds but are not considered in global and chemical transport models. We address this with a version of the PM-CAMx model that considers such organic water effects and use it to carry out 1-year aerosol simulations over the continental US. We show that such organic water impacts can increase dry PM1 levels by up to 2 μg m-3 when RH levels and PM1 concentrations are high.
Leong Wai Siu, Joseph S. Schlosser, David Painemal, Brian Cairns, Marta A. Fenn, Richard A. Ferrare, Johnathan W. Hair, Chris A. Hostetler, Longlei Li, Mary M. Kleb, Amy Jo Scarino, Taylor J. Shingler, Armin Sorooshian, Snorre A. Stamnes, and Xubin Zeng
Atmos. Meas. Tech. Discuss.,
Preprint under review for AMTShort summary
A comprehensive 3-year aerosol dataset was collected from a recent field campaign, which offers a special opportunity to evaluate two remote sensing instruments, one lidar and the other polarimeter, on the same aircraft. Special attention was paid to validate field data and their uncertainties when no reference dataset is available. A simple filter was developed to better quality control the polarimeter aerosol data. Physical reasons for the disagreement between two instruments were discussed.
Simon Kirschler, Christiane Voigt, Bruce E. Anderson, Gao Chen, Ewan C. Crosbie, Richard A. Ferrare, Valerian Hahn, Johnathan W. Hair, Stefan Kaufmann, Richard H. Moore, David Painemal, Claire E. Robinson, Kevin J. Sanchez, Amy J. Scarino, Taylor J. Shingler, Michael A. Shook, Kenneth L. Thornhill, Edward L. Winstead, Luke D. Ziemba, and Armin Sorooshian
Atmos. Chem. Phys., 23, 10731–10750,Short summary
In this study we present an overview of liquid and mixed-phase clouds and precipitation in the marine boundary layer over the western North Atlantic Ocean. We compare microphysical properties of pure liquid clouds to mixed-phase clouds and show that the initiation of the ice phase in mixed-phase clouds promotes precipitation. The observational data presented in this study are well suited for investigating the processes that give rise to liquid and mixed-phase clouds, ice, and precipitation.
Guangyu Li, Elise K. Wilbourn, Zezhen Cheng, Jörg Wieder, Allison Fagerson, Jan Henneberger, Ghislain Motos, Rita Traversi, Sarah D. Brooks, Mauro Mazzola, Swarup China, Athanasios Nenes, Ulrike Lohmann, Naruki Hiranuma, and Zamin A. Kanji
Atmos. Chem. Phys., 23, 10489–10516,Short summary
In this work, we present results from an Arctic field campaign (NASCENT) in Ny-Ålesund, Svalbard, on the abundance, variability, physicochemical properties, and potential sources of ice-nucleating particles (INPs) relevant for mixed-phase cloud formation. This work improves the data coverage of Arctic INPs and aerosol properties, allowing for the validation of models predicting cloud microphysical and radiative properties of mixed-phase clouds in the rapidly warming Arctic.
Sanja Dmitrovic, Johnathan W. Hair, Brian L. Collister, Ewan Crosbie, Marta A. Fenn, Richard A. Ferrare, David B. Harper, Chris A. Hostetler, Yongxiang Hu, John A. Reagan, Claire E. Robinson, Shane T. Seaman, Taylor J. Shingler, Kenneth L. Thornhill, Holger Vömel, Xubin Zeng, and Armin Sorooshian
This study introduces and evaluates a new ocean surface wind speed product from NASA Langley Research Center’s (LARC’s) airborne High Spectral Resolution Lidar – generation 2 (HSRL-2) using NASA ACTIVATE field data. We show that HSRL-2 wind speed retrievals have small errors when compared to wind speeds directly measured by NCAR AVAPS dropsondes. This novel retrieval method provides a way to obtain accurate, high resolution wind speed data in airborne field campaigns.
Anne-Claire Billault-Roux, Paraskevi Georgakaki, Josué Gehring, Louis Jaffeux, Alfons Schwarzenboeck, Pierre Coutris, Athanasios Nenes, and Alexis Berne
Atmos. Chem. Phys., 23, 10207–10234,Short summary
Secondary ice production plays a key role in clouds and precipitation. In this study, we analyze radar measurements from a snowfall event in the Jura Mountains. Complex signatures are observed, which reveal that ice crystals were formed through various processes. An analysis of multi-sensor data suggests that distinct ice multiplication processes were taking place. Both the methods used and the insights gained through this case study contribute to a better understanding of snowfall microphysics.
Mária Lbadaoui-Darvas, Ari Laaksonen, and Athanasios Nenes
Atmos. Chem. Phys., 23, 10057–10074,Short summary
Heterogeneous ice nucleation is the main ice formation mechanism in clouds. The mechanism of different freezing modes is to date unknown, which results in large model biases. Experiments do not allow for direct observation of ice nucleation at its native resolution. This work uses first principles molecular simulations to determine the mechanism of the least-understood ice nucleation mode and link it to adsorption through a novel modeling framework that unites ice and droplet formation.
Alexandros Milousis, Alexandra P. Tsimpidi, Holger Tost, Spyros N. Pandis, Athanasios Nenes, Astrid Kiendler-Scharr, and Vlassis A. Karydis
Geosci. Model Dev. Discuss.,
Preprint under review for GMDShort summary
This study aims to evaluate the newly developed ISORROPIA-lite aerosol thermodynamic module within the EMAC model and explore discrepancies in global atmospheric simulations of aerosol composition and acidity by utilizing different aerosol phase states. Even though local differences were found in regions where the RH ranged from 20 % to 60 %, on a global scale the results are similar. Therefore, ISORROPIA-lite can be a reliable and computationally effective replacement of ISORROPIA-II in EMAC.
Qian Xiao, Jiaoshi Zhang, Yang Wang, Luke D. Ziemba, Ewan Crosbie, Edward L. Winstead, Claire E. Robinson, Joshua P. DiGangi, Glenn S. Diskin, Jeffrey S. Reid, K. Sebastian Schmidt, Armin Sorooshian, Miguel Ricardo A. Hilario, Sarah Woods, Paul Lawson, Snorre A. Stamnes, and Jian Wang
Atmos. Chem. Phys., 23, 9853–9871,Short summary
Using recent airborne measurements, we show that the influences of anthropogenic emissions, transport, convective clouds, and meteorology lead to new particle formation (NPF) under a variety of conditions and at different altitudes in tropical marine environments. NPF is enhanced by fresh urban emissions in convective outflow but is suppressed in air masses influenced by aged urban emissions where reactive precursors are mostly consumed while particle surface area remains relatively high.
Meng Gao, Bryan A. Franz, Peng-Wang Zhai, Kirk Knobelspiesse, Andrew Sayer, Xiaoguang Xu, Vanderlei Martins, Brian Cairns, Patricia Castellanos, Guangliang Fu, Neranga Hannadige, Otto Hasekamp, Yongxiang Hu, Amir Ibrahim, Frederick Patt, Anin Puthukkudy, and P. Jeremy Werdell
This study evaluates the retrievability and uncertainty on aerosol and ocean parameter from PACE's HARP2 instrument using enhanced neural network models within the FastMAPOL algorithm. The approach streamlined data processing and utilized a cascading retrieval method for optimization. Testing with synthetic HARP2 data revealed reliable retrieval of aerosol properties, though with some uncertainties in other areas. Overall, the algorithm is effective and viable for operational data analysis.
Hiren Jethva, Omar Torres, Richard Ferrare, Sharon Burton, Anthony Cook, David Harper, Chris Hostetler, Jens Redemann, Vinay Kayetha, Samuel LeBlanc, Kristina Pistone, Logan Mitchell, and Connor Flynn
We introduce a novel synergy algorithm applied to ORALCES airborne measurements of above-cloud aerosol optical depth and UV-VIS satellite observations from OMI and MODIS to retrieve spectral aerosol single-scattering albedo of lofted layers of carbonaceous smoke aerosols over clouds. The development of the proposed aerosol-cloud algorithm implies a possible synergy of CALIOP lidar and OMI-MODIS passive sensors to deduce a global product of ACAOD and SSA.
Armin Sorooshian, Mikhail D. Alexandrov, Adam D. Bell, Ryan Bennett, Grace Betito, Sharon P. Burton, Megan E. Buzanowicz, Brian Cairns, Eduard V. Chemyakin, Gao Chen, Yonghoon Choi, Brian L. Collister, Anthony L. Cook, Andrea F. Corral, Ewan C. Crosbie, Bastiaan van Diedenhoven, Joshua P. DiGangi, Glenn S. Diskin, Sanja Dmitrovic, Eva-Lou Edwards, Marta A. Fenn, Richard A. Ferrare, David van Gilst, Johnathan W. Hair, David B. Harper, Miguel Ricardo A. Hilario, Chris A. Hostetler, Nathan Jester, Michael Jones, Simon Kirschler, Mary M. Kleb, John M. Kusterer, Sean Leavor, Joseph W. Lee, Hongyu Liu, Kayla McCauley, Richard H. Moore, Joseph Nied, Anthony Notari, John B. Nowak, David Painemal, Kasey E. Phillips, Claire E. Robinson, Amy Jo Scarino, Joseph S. Schlosser, Shane T. Seaman, Chellappan Seethala, Taylor J. Shingler, Michael A. Shook, Kenneth A. Sinclair, William L. Smith Jr., Douglas A. Spangenberg, Snorre A. Stamnes, Kenneth L. Thornhill, Christiane Voigt, Holger Vömel, Andrzej P. Wasilewski, Hailong Wang, Edward L. Winstead, Kira Zeider, Xubin Zeng, Bo Zhang, Luke D. Ziemba, and Paquita Zuidema
Earth Syst. Sci. Data, 15, 3419–3472,Short summary
The NASA Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) produced a unique dataset for research into aerosol–cloud–meteorology interactions. HU-25 Falcon and King Air aircraft conducted systematic and spatially coordinated flights over the northwest Atlantic Ocean. This paper describes the ACTIVATE flight strategy, instrument and complementary dataset products, data access and usage details, and data application notes.
Amir Yazdani, Satoshi Takahama, John K. Kodros, Marco Paglione, Mauro Masiol, Stefania Squizzato, Kalliopi Florou, Christos Kaltsonoudis, Spiro D. Jorga, Spyros N. Pandis, and Athanasios Nenes
Atmos. Chem. Phys., 23, 7461–7477,Short summary
Organic aerosols directly emitted from wood and pellet stove combustion are found to chemically transform (approximately 15 %–35 % by mass) under daytime aging conditions simulated in an environmental chamber. A new marker for lignin-like compounds is found to degrade at a different rate than previously identified biomass burning markers and can potentially provide indication of aging time in ambient samples.
Brent A. McBride, J. Vanderlei Martins, J. Dominik Cieslak, Roberto Fernandez-Borda, Anin Puthukuddy, Xiaoguang Xu, Noah Sienkiewicz, Brian Cairns, and Henrique M. J. Barbosa
The Airborne Hyper-Angular Rainbow Polarimeter (AirHARP) is a new Earth-observing instrument that can provide highly accurate measurements of the atmosphere and surface. Using a physics-based calibration technique, we show that AirHARP can achieve high measurement accuracy in lab and field environments and exceed a benchmark accuracy requirement for modern aerosol and cloud climate observations. Our calibration technique makes the HARP design highly attractive for upcoming NASA climate missions.
Haihui Zhu, Randall V. Martin, Betty Croft, Shixian Zhai, Chi Li, Liam Bindle, Jeffrey R. Pierce, Rachel Y.-W. Chang, Bruce E. Anderson, Luke D. Ziemba, Johnathan W. Hair, Richard A. Ferrare, Chris A. Hostetler, Inderjeet Singh, Deepangsu Chatterjee, Jose L. Jimenez, Pedro Campuzano-Jost, Benjamin A. Nault, Jack E. Dibb, Joshua S. Schwarz, and Andrew Weinheimer
Atmos. Chem. Phys., 23, 5023–5042,Short summary
Particle size of atmospheric aerosol is important for estimating its climate and health effects, but simulating atmospheric aerosol size is computationally demanding. This study derives a simple parameterization of the size of organic and secondary inorganic ambient aerosol that can be applied to atmospheric models. Applying this parameterization allows a better representation of the global spatial pattern of aerosol size, as verified by ground and airborne measurements.
Amie Dobracki, Paquita Zuidema, Steven G. Howell, Pablo Saide, Steffen Freitag, Allison C. Aiken, Sharon P. Burton, Arthur J. Sedlacek III, Jens Redemann, and Robert Wood
Atmos. Chem. Phys., 23, 4775–4799,Short summary
Southern Africa produces approximately one-third of the world’s carbon from fires. The thick smoke layer can flow westward, interacting with the southeastern Atlantic cloud deck. The net radiative impact can alter regional circulation patterns, impacting rainfall over Africa. We find that the smoke is highly absorbing of sunlight, mostly because it contains more black carbon than smoke over the Northern Hemisphere.
Meng Gao, Kirk Knobelspiesse, Bryan A. Franz, Peng-Wang Zhai, Brian Cairns, Xiaoguang Xu, and J. Vanderlei Martins
Atmos. Meas. Tech., 16, 2067–2087,Short summary
Multi-angle polarimetric measurements have been shown to greatly improve the remote sensing capability of aerosols and help atmospheric correction for ocean color retrievals. However, the uncertainty correlations among different measurement angles have not been well characterized. In this work, we provided a practical framework to evaluate the impact of the angular uncertainty correlation in retrieval results and a method to directly estimate correlation strength from retrieval residuals.
Ian Chang, Lan Gao, Connor J. Flynn, Yohei Shinozuka, Sarah J. Doherty, Michael S. Diamond, Karla M. Longo, Gonzalo A. Ferrada, Gregory R. Carmichael, Patricia Castellanos, Arlindo M. da Silva, Pablo E. Saide, Calvin Howes, Zhixin Xue, Marc Mallet, Ravi Govindaraju, Qiaoqiao Wang, Yafang Cheng, Yan Feng, Sharon P. Burton, Richard A. Ferrare, Samuel E. LeBlanc, Meloë S. Kacenelenbogen, Kristina Pistone, Michal Segal-Rozenhaimer, Kerry G. Meyer, Ju-Mee Ryoo, Leonhard Pfister, Adeyemi A. Adebiyi, Robert Wood, Paquita Zuidema, Sundar A. Christopher, and Jens Redemann
Atmos. Chem. Phys., 23, 4283–4309,Short summary
Abundant aerosols are present above low-level liquid clouds over the southeastern Atlantic during late austral spring. The model simulation differences in the proportion of aerosol residing in the planetary boundary layer and in the free troposphere can greatly affect the regional aerosol radiative effects. This study examines the aerosol loading and fractional aerosol loading in the free troposphere among various models and evaluates them against measurements from the NASA ORACLES campaign.
Kai Krause, Folkard Wittrock, Andreas Richter, Dieter Busch, Anton Bergen, John P. Burrows, Steffen Freitag, and Olesia Halbherr
Atmos. Meas. Tech., 16, 1767–1787,Short summary
Inland shipping is an important source of nitrogen oxides (NOx). The amount of emitted NOx depends on the characteristics of the individual vessels and the traffic density. Ship emissions are often characterised by the amount of emitted NOx per unit of burnt fuel, and further knowledge about fuel consumption is needed to quantify the total emissions caused by ship traffic. In this study, a new approach to derive absolute emission rates (in g s−1) from onshore measurements is presented.
Andrew M. Sayer, Luca Lelli, Brian Cairns, Bastiaan van Diedenhoven, Amir Ibrahim, Kirk D. Knobelspiesse, Sergey Korkin, and P. Jeremy Werdell
Atmos. Meas. Tech., 16, 969–996,Short summary
This paper presents a method to estimate the height of the top of clouds above Earth's surface using satellite measurements. It is based on light absorption by oxygen in Earth's atmosphere, which darkens the signal that a satellite will see at certain wavelengths of light. Clouds "shield" the satellite from some of this darkening, dependent on cloud height (and other factors), because clouds scatter light at these wavelengths. The method will be applied to the future NASA PACE mission.
Marios Chatziparaschos, Nikos Daskalakis, Stelios Myriokefalitakis, Nikos Kalivitis, Athanasios Nenes, María Gonçalves Ageitos, Montserrat Costa-Surós, Carlos Pérez García-Pando, Medea Zanoli, Mihalis Vrekoussis, and Maria Kanakidou
Atmos. Chem. Phys., 23, 1785–1801,Short summary
Ice formation is enabled by ice-nucleating particles (INP) at higher temperatures than homogeneous formation and can profoundly affect the properties of clouds. Our global model results show that K-feldspar is the most important contributor to INP concentrations globally, affecting mid-level mixed-phase clouds. However, quartz can significantly contribute and dominates the lowest and the highest altitudes of dust-derived INP, affecting mainly low-level and high-level mixed-phase clouds.
Francesca Gallo, Kevin J. Sanchez, Bruce E. Anderson, Ryan Bennett, Matthew D. Brown, Ewan C. Crosbie, Chris Hostetler, Carolyn Jordan, Melissa Yang Martin, Claire E. Robinson, Lynn M. Russell, Taylor J. Shingler, Michael A. Shook, Kenneth L. Thornhill, Elizabeth B. Wiggins, Edward L. Winstead, Armin Wisthaler, Luke D. Ziemba, and Richard H. Moore
Atmos. Chem. Phys., 23, 1465–1490,Short summary
We integrate in situ ship- and aircraft-based measurements of aerosol, trace gases, and meteorological parameters collected during the NASA North Atlantic Aerosols and Marine Ecosystems Study (NAAMES) field campaigns in the western North Atlantic Ocean region. A comprehensive characterization of the vertical profiles of aerosol properties under different seasonal regimes is provided for improving the understanding of aerosol key processes and aerosol–cloud interactions in marine regions.
Bastiaan van Diedenhoven, Otto P. Hasekamp, Brian Cairns, Gregory L. Schuster, Snorre Stamnes, Michael Shook, and Luke Ziemba
Atmos. Meas. Tech., 15, 7411–7434,Short summary
The strong variability in the chemistry of atmospheric particulate matter affects the amount of water aerosols absorb and their effect on climate. We present a remote sensing method to determine the amount of water in particulate matter. Its application to airborne instruments indicates that the observed aerosols have rather low water contents and low fractions of soluble particles. Future satellites will be able to yield global aerosol water uptake data.
Allison B. Marquardt Collow, Virginie Buchard, Peter R. Colarco, Arlindo M. da Silva, Ravi Govindaraju, Edward P. Nowottnick, Sharon Burton, Richard Ferrare, Chris Hostetler, and Luke Ziemba
Atmos. Chem. Phys., 22, 16091–16109,Short summary
Biomass burning aerosol impacts aspects of the atmosphere and Earth system through radiative forcing, serving as cloud condensation nuclei, and air quality. Despite its importance, the representation of biomass burning aerosol is not always accurate in models. Field campaign observations from CAMP2Ex are used to evaluate the mass and extinction of aerosols in the GEOS model. Notable biases in the model illuminate areas of future development with GEOS and the underlying GOCART aerosol module.
Ju-Mee Ryoo, Leonhard Pfister, Rei Ueyama, Paquita Zuidema, Robert Wood, Ian Chang, and Jens Redemann
Atmos. Chem. Phys., 22, 14209–14241,Short summary
The variability in the meteorological fields during each deployment is highly modulated at a daily to synoptic timescale. This paper, along with part 1, the climatological overview paper, provides a meteorological context for interpreting the airborne measurements gathered during the three ORACLES deployments. This study supports related studies focusing on the detailed investigation of the processes controlling stratocumulus decks, aerosol lifting, transport, and their interactions.
Paul A. Barrett, Steven J. Abel, Hugh Coe, Ian Crawford, Amie Dobracki, James Haywood, Steve Howell, Anthony Jones, Justin Langridge, Greg M. McFarquhar, Graeme J. Nott, Hannah Price, Jens Redemann, Yohei Shinozuka, Kate Szpek, Jonathan W. Taylor, Robert Wood, Huihui Wu, Paquita Zuidema, Stéphane Bauguitte, Ryan Bennett, Keith Bower, Hong Chen, Sabrina Cochrane, Michael Cotterell, Nicholas Davies, David Delene, Connor Flynn, Andrew Freedman, Steffen Freitag, Siddhant Gupta, David Noone, Timothy B. Onasch, James Podolske, Michael R. Poellot, Sebastian Schmidt, Stephen Springston, Arthur J. Sedlacek III, Jamie Trembath, Alan Vance, Maria A. Zawadowicz, and Jianhao Zhang
Atmos. Meas. Tech., 15, 6329–6371,Short summary
To better understand weather and climate, it is vital to go into the field and collect observations. Often measurements take place in isolation, but here we compared data from two aircraft and one ground-based site. This was done in order to understand how well measurements made on one platform compared to those made on another. Whilst this is easy to do in a controlled laboratory setting, it is more challenging in the real world, and so these comparisons are as valuable as they are rare.
Piyushkumar Patel, Jonathan Jiang, Ritesh Gautam, Harish Gadhavi, Olga Kalashnikova, Michael Garay, Lan Gao, Feng Xu, and Ali Omar
Atmos. Chem. Phys. Discuss.,
Preprint under review for ACPShort summary
The lack of global measurements of cloud condensation nuclei (CCN) prevents detailed testing of aerosol-cloud effects and predicting climate change. Therefore, we developed a novel remote sensing-based algorithm for retrieving vertically resolved CCN number concentrations from the spaceborne lidar system. This new capability provides global distribution of CCN number concentrations from space that will be beneficial for evaluating models and accurately quantifying aerosol climate forcing.
Eva-Lou Edwards, Jeffrey S. Reid, Peng Xian, Sharon P. Burton, Anthony L. Cook, Ewan C. Crosbie, Marta A. Fenn, Richard A. Ferrare, Sean W. Freeman, John W. Hair, David B. Harper, Chris A. Hostetler, Claire E. Robinson, Amy Jo Scarino, Michael A. Shook, G. Alexander Sokolowsky, Susan C. van den Heever, Edward L. Winstead, Sarah Woods, Luke D. Ziemba, and Armin Sorooshian
Atmos. Chem. Phys., 22, 12961–12983,Short summary
This study compares NAAPS-RA model simulations of aerosol optical thickness (AOT) and extinction to those retrieved with a high spectral resolution lidar near the Philippines. Agreement for AOT was good, and extinction agreement was strongest below 1500 m. Substituting dropsonde relative humidities into NAAPS-RA did not drastically improve agreement, and we discuss potential reasons why. Accurately modeling future conditions in this region is crucial due to its susceptibility to climate change.
Siddhant Gupta, Greg M. McFarquhar, Joseph R. O'Brien, Michael R. Poellot, David J. Delene, Ian Chang, Lan Gao, Feng Xu, and Jens Redemann
Atmos. Chem. Phys., 22, 12923–12943,Short summary
The ability of NASA’s Terra and Aqua satellites to retrieve cloud properties and estimate the changes in cloud properties due to aerosol–cloud interactions (ACI) was examined. There was good agreement between satellite retrievals and in situ measurements over the southeast Atlantic Ocean. This suggests that, combined with information on aerosol properties, satellite retrievals of cloud properties can be used to study ACI over larger domains and longer timescales in the absence of in situ data.
Michael S. Diamond, Pablo E. Saide, Paquita Zuidema, Andrew S. Ackerman, Sarah J. Doherty, Ann M. Fridlind, Hamish Gordon, Calvin Howes, Jan Kazil, Takanobu Yamaguchi, Jianhao Zhang, Graham Feingold, and Robert Wood
Atmos. Chem. Phys., 22, 12113–12151,Short summary
Smoke from southern Africa blankets the southeast Atlantic from June-October, overlying a major transition region between overcast and scattered clouds. The smoke affects Earth's radiation budget by absorbing sunlight and changing cloud properties. We investigate these effects in regional climate and large eddy simulation models based on international field campaigns. We find that large-scale circulation changes more strongly affect cloud transitions than smoke microphysical effects in our case.
Samuel E. LeBlanc, Michal Segal-Rozenhaimer, Jens Redemann, Connor Flynn, Roy R. Johnson, Stephen E. Dunagan, Robert Dahlgren, Jhoon Kim, Myungje Choi, Arlindo da Silva, Patricia Castellanos, Qian Tan, Luke Ziemba, Kenneth Lee Thornhill, and Meloë Kacenelenbogen
Atmos. Chem. Phys., 22, 11275–11304,Short summary
Airborne observations of atmospheric particles and pollution over Korea during a field campaign in May–June 2016 showed that the smallest atmospheric particles are present in the lowest 2 km of the atmosphere. The aerosol size is more spatially variable than optical thickness. We show this with remote sensing (4STAR), in situ (LARGE) observations, satellite measurements (GOCI), and modeled properties (MERRA-2), and it is contrary to the current understanding.
Meng Gao, Kirk Knobelspiesse, Bryan A. Franz, Peng-Wang Zhai, Andrew M. Sayer, Amir Ibrahim, Brian Cairns, Otto Hasekamp, Yongxiang Hu, Vanderlei Martins, P. Jeremy Werdell, and Xiaoguang Xu
Atmos. Meas. Tech., 15, 4859–4879,Short summary
In this work, we assessed the pixel-wise retrieval uncertainties on aerosol and ocean color derived from multi-angle polarimetric measurements. Standard error propagation methods are used to compute the uncertainties. A flexible framework is proposed to evaluate how representative these uncertainties are compared with real retrieval errors. Meanwhile, to assist operational data processing, we optimized the computational speed to evaluate the retrieval uncertainties based on neural networks.
Harshvardhan Harshvardhan, Richard Ferrare, Sharon Burton, Johnathan Hair, Chris Hostetler, David Harper, Anthony Cook, Marta Fenn, Amy Jo Scarino, Eduard Chemyakin, and Detlef Müller
Atmos. Chem. Phys., 22, 9859–9876,Short summary
The evolution of aerosol in biomass burning smoke plumes that travel over marine clouds off the Atlantic coast of central Africa was studied using measurements made by a lidar deployed on a high-altitude aircraft. The main finding was that the physical properties of aerosol do not change appreciably once the plume has left land and travels over the ocean over a timescale of 1 to 2 d. Almost all particles in the plume are of radius less than 1 micrometer and spherical in shape.
Caroline Dang, Michal Segal-Rozenhaimer, Haochi Che, Lu Zhang, Paola Formenti, Jonathan Taylor, Amie Dobracki, Sara Purdue, Pui-Shan Wong, Athanasios Nenes, Arthur Sedlacek III, Hugh Coe, Jens Redemann, Paquita Zuidema, Steven Howell, and James Haywood
Atmos. Chem. Phys., 22, 9389–9412,Short summary
Transmission electron microscopy was used to analyze aged African smoke particles and how the smoke interacts with the marine atmosphere. We found that the volatility of organic aerosol increases with biomass burning plume age, that black carbon is often mixed with potassium salts and that the marine atmosphere can incorporate Na and Cl into smoke particles. Marine salts are more processed when mixed with smoke plumes, and there are interesting Cl-rich yet Na-absent marine particles.
Lu Zhang, Michal Segal-Rozenhaimer, Haochi Che, Caroline Dang, Arthur J. Sedlacek III, Ernie R. Lewis, Amie Dobracki, Jenny P. S. Wong, Paola Formenti, Steven G. Howell, and Athanasios Nenes
Atmos. Chem. Phys., 22, 9199–9213,Short summary
Widespread biomass burning (BB) events occur annually in Africa and contribute ~ 1 / 3 of global BB emissions, which contain a large family of light-absorbing organics, known as brown carbon (BrC), whose absorption of incident radiation is difficult to estimate, leading to large uncertainties in the global radiative forcing estimation. This study quantifies the BrC absorption of aged BB particles and highlights the potential presence of absorbing iron oxides in this climatically important region.
Simon Kirschler, Christiane Voigt, Bruce Anderson, Ramon Campos Braga, Gao Chen, Andrea F. Corral, Ewan Crosbie, Hossein Dadashazar, Richard A. Ferrare, Valerian Hahn, Johannes Hendricks, Stefan Kaufmann, Richard Moore, Mira L. Pöhlker, Claire Robinson, Amy J. Scarino, Dominik Schollmayer, Michael A. Shook, K. Lee Thornhill, Edward Winstead, Luke D. Ziemba, and Armin Sorooshian
Atmos. Chem. Phys., 22, 8299–8319,Short summary
In this study we show that the vertical velocity dominantly impacts the cloud droplet number concentration (NC) of low-level clouds over the western North Atlantic in the winter and summer season, while the cloud condensation nuclei concentration, aerosol size distribution and chemical composition impact NC within a season. The observational data presented in this study can evaluate and improve the representation of aerosol–cloud interactions for a wide range of conditions.
Dongwei Fu, Larry Di Girolamo, Robert M. Rauber, Greg M. McFarquhar, Stephen W. Nesbitt, Jesse Loveridge, Yulan Hong, Bastiaan van Diedenhoven, Brian Cairns, Mikhail D. Alexandrov, Paul Lawson, Sarah Woods, Simone Tanelli, Sebastian Schmidt, Chris Hostetler, and Amy Jo Scarino
Atmos. Chem. Phys., 22, 8259–8285,Short summary
Satellite-retrieved cloud microphysics are widely used in climate research because of their central role in water and energy cycles. Here, we provide the first detailed investigation of retrieved cloud drop sizes from in situ and various satellite and airborne remote sensing techniques applied to real cumulus cloud fields. We conclude that the most widely used passive remote sensing method employed in climate research produces high biases of 6–8 µm (60 %–80 %) caused by 3-D radiative effects.
Zhujun Li, David Painemal, Gregory Schuster, Marian Clayton, Richard Ferrare, Mark Vaughan, Damien Josset, Jayanta Kar, and Charles Trepte
Atmos. Meas. Tech., 15, 2745–2766,Short summary
For more than 15 years, CALIPSO has revolutionized our understanding of the role of aerosols in climate. Here we evaluate CALIPSO aerosol typing over the ocean using an independent CALIPSO–CloudSat product. The analysis suggests that CALIPSO correctly categorizes clean marine aerosol over the open ocean, elevated smoke over the SE Atlantic, and dust over the tropical Atlantic. Similarities between clean and dusty marine over the open ocean implies that algorithm modifications are warranted.
Stelios Myriokefalitakis, Elisa Bergas-Massó, María Gonçalves-Ageitos, Carlos Pérez García-Pando, Twan van Noije, Philippe Le Sager, Akinori Ito, Eleni Athanasopoulou, Athanasios Nenes, Maria Kanakidou, Maarten C. Krol, and Evangelos Gerasopoulos
Geosci. Model Dev., 15, 3079–3120,Short summary
We here describe the implementation of atmospheric multiphase processes in the EC-Earth Earth system model. We provide global budgets of oxalate, sulfate, and iron-containing aerosols, along with an analysis of the links among atmospheric composition, aqueous-phase processes, and aerosol dissolution, supported by comparison to observations. This work is a first step towards an interactive calculation of the deposition of bioavailable atmospheric iron coupled to the model’s ocean component.
Meloë S. F. Kacenelenbogen, Qian Tan, Sharon P. Burton, Otto P. Hasekamp, Karl D. Froyd, Yohei Shinozuka, Andreas J. Beyersdorf, Luke Ziemba, Kenneth L. Thornhill, Jack E. Dibb, Taylor Shingler, Armin Sorooshian, Reed W. Espinosa, Vanderlei Martins, Jose L. Jimenez, Pedro Campuzano-Jost, Joshua P. Schwarz, Matthew S. Johnson, Jens Redemann, and Gregory L. Schuster
Atmos. Chem. Phys., 22, 3713–3742,Short summary
The impact of aerosols on Earth's radiation budget and human health is important and strongly depends on their composition. One desire of our scientific community is to derive the composition of the aerosol from satellite sensors. However, satellites observe aerosol optical properties (and not aerosol composition) based on remote sensing instrumentation. This study assesses how much aerosol optical properties can tell us about aerosol composition.
Matthew S. Norgren, John Wood, K. Sebastian Schmidt, Bastiaan van Diedenhoven, Snorre A. Stamnes, Luke D. Ziemba, Ewan C. Crosbie, Michael A. Shook, A. Scott Kittelman, Samuel E. LeBlanc, Stephen Broccardo, Steffen Freitag, and Jeffrey S. Reid
Atmos. Meas. Tech., 15, 1373–1394,Short summary
A new spectral instrument (SPN-S), with the ability to partition solar radiation into direct and diffuse components, is used in airborne settings to study the optical properties of aerosols and cirrus. It is a low-cost and mechanically simple system but has higher measurement uncertainty than existing standards. This challenge is overcome by utilizing the unique measurement capabilities to develop new retrieval techniques. Validation is done with data from two NASA airborne research campaigns.
Kevin J. Sanchez, Bo Zhang, Hongyu Liu, Matthew D. Brown, Ewan C. Crosbie, Francesca Gallo, Johnathan W. Hair, Chris A. Hostetler, Carolyn E. Jordan, Claire E. Robinson, Amy Jo Scarino, Taylor J. Shingler, Michael A. Shook, Kenneth L. Thornhill, Elizabeth B. Wiggins, Edward L. Winstead, Luke D. Ziemba, Georges Saliba, Savannah L. Lewis, Lynn M. Russell, Patricia K. Quinn, Timothy S. Bates, Jack Porter, Thomas G. Bell, Peter Gaube, Eric S. Saltzman, Michael J. Behrenfeld, and Richard H. Moore
Atmos. Chem. Phys., 22, 2795–2815,Short summary
Atmospheric particle concentrations impact clouds, which strongly impact the amount of sunlight reflected back into space and the overall climate. Measurements of particles over the ocean are rare and expensive to collect, so models are necessary to fill in the gaps by simulating both particle and clouds. However, some measurements are needed to test the accuracy of the models. Here, we measure changes in particles in different weather conditions, which are ideal for comparison with models.
Paraskevi Georgakaki, Georgia Sotiropoulou, Étienne Vignon, Anne-Claire Billault-Roux, Alexis Berne, and Athanasios Nenes
Atmos. Chem. Phys., 22, 1965–1988,Short summary
The modelling study focuses on the importance of ice multiplication processes in orographic mixed-phase clouds, which is one of the least understood cloud types in the climate system. We show that the consideration of ice seeding and secondary ice production through ice–ice collisional breakup is essential for correct predictions of precipitation in mountainous terrain, with important implications for radiation processes.
Sabrina P. Cochrane, K. Sebastian Schmidt, Hong Chen, Peter Pilewskie, Scott Kittelman, Jens Redemann, Samuel LeBlanc, Kristina Pistone, Michal Segal Rozenhaimer, Meloë Kacenelenbogen, Yohei Shinozuka, Connor Flynn, Rich Ferrare, Sharon Burton, Chris Hostetler, Marc Mallet, and Paquita Zuidema
Atmos. Meas. Tech., 15, 61–77,Short summary
This work presents heating rates derived from aircraft observations from the 2016 and 2017 field campaigns of ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS). We separate the total heating rates into aerosol and gas (primarily water vapor) absorption and explore some of the co-variability of heating rate profiles and their primary drivers, leading to the development of a new concept: the heating rate efficiency (HRE; the heating rate per unit aerosol extinction).
Sarah J. Doherty, Pablo E. Saide, Paquita Zuidema, Yohei Shinozuka, Gonzalo A. Ferrada, Hamish Gordon, Marc Mallet, Kerry Meyer, David Painemal, Steven G. Howell, Steffen Freitag, Amie Dobracki, James R. Podolske, Sharon P. Burton, Richard A. Ferrare, Calvin Howes, Pierre Nabat, Gregory R. Carmichael, Arlindo da Silva, Kristina Pistone, Ian Chang, Lan Gao, Robert Wood, and Jens Redemann
Atmos. Chem. Phys., 22, 1–46,Short summary
Between July and October, biomass burning smoke is advected over the southeastern Atlantic Ocean, leading to climate forcing. Model calculations of forcing by this plume vary significantly in both magnitude and sign. This paper compares aerosol and cloud properties observed during three NASA ORACLES field campaigns to the same in four models. It quantifies modeled biases in properties key to aerosol direct radiative forcing and evaluates how these biases propagate to biases in forcing.
Amie Dobracki, Paquita Zuidema, Steve Howell, Pablo Saide, Steffen Freitag, Allison C. Aiken, Sharon P. Burton, Arthur J. Sedlacek III, Jens Redemann, and Robert Wood
Atmos. Chem. Phys. Discuss.,
Preprint withdrawnShort summary
The global maximum of shortwave-absorbing aerosol above cloud occurs above the southeast Atlantic, where the biomass-burning aerosol provides a distinct aerosol radiative warming of regional climate. The smoke aerosols are unusually highly absorbing of sunlight. This study seeks to understand the cause. We conclude the aerosol is already strongly absorbing at the fire emission source, but that chemical aging, through encouraging a net loss of organic aerosol, also contributes.
Irini Tsiodra, Georgios Grivas, Kalliopi Tavernaraki, Aikaterini Bougiatioti, Maria Apostolaki, Despina Paraskevopoulou, Alexandra Gogou, Constantine Parinos, Konstantina Oikonomou, Maria Tsagkaraki, Pavlos Zarmpas, Athanasios Nenes, and Nikolaos Mihalopoulos
Atmos. Chem. Phys., 21, 17865–17883,Short summary
We analyze observations from year-long measurements at Athens, Greece. Nighttime wintertime PAH levels are 4 times higher than daytime, and wintertime values are 15 times higher than summertime. Biomass burning aerosol during wintertime pollution events is responsible for these significant wintertime enhancements and accounts for 43 % of the population exposure to PAH carcinogenic risk. Biomass burning poses additional health risks beyond those associated with the high PM levels that develop.
Mária Lbadaoui-Darvas, Satoshi Takahama, and Athanasios Nenes
Atmos. Chem. Phys., 21, 17687–17714,Short summary
Aerosol–cloud interactions constitute the most uncertain contribution to climate change. The uptake kinetics of water by aerosol is a central process of cloud droplet formation, yet its molecular-scale mechanism is unknown. We use molecular simulations to study this process for phase-separated organic particles. Our results explain the increased cloud condensation activity of such particles and can be generalized over various compositions, thus possibly serving as a basis for future models.
Steven G. Howell, Steffen Freitag, Amie Dobracki, Nikolai Smirnow, and Arthur J. Sedlacek III
Atmos. Meas. Tech., 14, 7381–7404,Short summary
Small particles in the air have important effects on visibility, clouds, and human health. For the ORACLES project we got a new particle sizing instrument that is fast, works over the most important particle sizes, and avoids some of the issues that plague other optical particle sizers. Unfortunately it sees some particles much smaller than they really are, likely because they heat up and evaporate. We show a crude correction and speculate why these particles heat up much more than expected.
Ju-Mee Ryoo, Leonhard Pfister, Rei Ueyama, Paquita Zuidema, Robert Wood, Ian Chang, and Jens Redemann
Atmos. Chem. Phys., 21, 16689–16707,Short summary
Part 1 of the meteorological overview paper highlights the anomalous meteorological characteristics during the ORACLES deployment compared to the climatological mean at monthly timescales. The upper-level wave disturbance and the associated anomalous circulation explain the weakening of AEJ-S through the reduction of the strength of the heat low over the land during August 2017. This may also help explain the anomalously low aerosol optical depth observed in the August 2017 ORACLES deployment.
David Painemal, Douglas Spangenberg, William L. Smith Jr., Patrick Minnis, Brian Cairns, Richard H. Moore, Ewan Crosbie, Claire Robinson, Kenneth L. Thornhill, Edward L. Winstead, and Luke Ziemba
Atmos. Meas. Tech., 14, 6633–6646,Short summary
Cloud properties derived from satellite sensors are critical for the global monitoring of climate. This study evaluates satellite-based cloud properties over the North Atlantic using airborne data collected during NAAMES. Satellite observations of droplet size and cloud optical depth tend to compare well with NAAMES data. The analysis indicates that the satellite pixel resolution and the specific viewing geometry need to be taken into account in research applications.
Spiro D. Jorga, Kalliopi Florou, Christos Kaltsonoudis, John K. Kodros, Christina Vasilakopoulou, Manuela Cirtog, Axel Fouqueau, Bénédicte Picquet-Varrault, Athanasios Nenes, and Spyros N. Pandis
Atmos. Chem. Phys., 21, 15337–15349,Short summary
We test the hypothesis that significant secondary organic aerosol production can take place even during winter nights through the oxidation of the emitted organic vapors by the nitrate radicals produced during the reaction of ozone and nitrogen oxides. Our experiments, using as a starting point the ambient air of an urban area with high biomass burning activity, demonstrate that, even with sunlight, there is 20 %–70 % additional organic aerosol formed in a few hours.
Zhao-Cheng Zeng, Vijay Natraj, Feng Xu, Sihe Chen, Fang-Ying Gong, Thomas J. Pongetti, Keeyoon Sung, Geoffrey Toon, Stanley P. Sander, and Yuk L. Yung
Atmos. Meas. Tech., 14, 6483–6507,Short summary
Large carbon source regions such as megacities are also typically associated with heavy aerosol loading, which introduces uncertainties in the retrieval of greenhouse gases from reflected and scattered sunlight measurements. In this study, we developed a full physics algorithm to retrieve greenhouse gases in the presence of aerosols and demonstrated its performance by retrieving CO2 and CH4 columns from remote sensing measurements in the Los Angeles megacity.
Rose M. Miller, Greg M. McFarquhar, Robert M. Rauber, Joseph R. O'Brien, Siddhant Gupta, Michal Segal-Rozenhaimer, Amie N. Dobracki, Arthur J. Sedlacek, Sharon P. Burton, Steven G. Howell, Steffen Freitag, and Caroline Dang
Atmos. Chem. Phys., 21, 14815–14831,Short summary
A large stratocumulus cloud deck resides off the west coast of central Africa. Biomass burning in Africa produces a large plume of aerosol that is carried by the wind over this stratocumulus cloud deck. This paper shows that particles with sizes from 0.01 to 1 mm reside within this plume. Past studies have shown that biomass burning produces such particles, but this is the first study to show that they can be transported westward, over long distances, to the Atlantic stratocumulus cloud deck.
Xinxin Ye, Pargoal Arab, Ravan Ahmadov, Eric James, Georg A. Grell, Bradley Pierce, Aditya Kumar, Paul Makar, Jack Chen, Didier Davignon, Greg R. Carmichael, Gonzalo Ferrada, Jeff McQueen, Jianping Huang, Rajesh Kumar, Louisa Emmons, Farren L. Herron-Thorpe, Mark Parrington, Richard Engelen, Vincent-Henri Peuch, Arlindo da Silva, Amber Soja, Emily Gargulinski, Elizabeth Wiggins, Johnathan W. Hair, Marta Fenn, Taylor Shingler, Shobha Kondragunta, Alexei Lyapustin, Yujie Wang, Brent Holben, David M. Giles, and Pablo E. Saide
Atmos. Chem. Phys., 21, 14427–14469,Short summary
Wildfire smoke has crucial impacts on air quality, while uncertainties in the numerical forecasts remain significant. We present an evaluation of 12 real-time forecasting systems. Comparison of predicted smoke emissions suggests a large spread in magnitudes, with temporal patterns deviating from satellite detections. The performance for AOD and surface PM2.5 and their discrepancies highlighted the role of accurately represented spatiotemporal emission profiles in improving smoke forecasts.
Andreas Tilgner, Thomas Schaefer, Becky Alexander, Mary Barth, Jeffrey L. Collett Jr., Kathleen M. Fahey, Athanasios Nenes, Havala O. T. Pye, Hartmut Herrmann, and V. Faye McNeill
Atmos. Chem. Phys., 21, 13483–13536,Short summary
Feedbacks of acidity and atmospheric multiphase chemistry in deliquesced particles and clouds are crucial for the tropospheric composition, depositions, climate, and human health. This review synthesizes the current scientific knowledge on these feedbacks using both inorganic and organic aqueous-phase chemistry. Finally, this review outlines atmospheric implications and highlights the need for future investigations with respect to reducing emissions of key acid precursors in a changing world.
Daniel Pérez-Ramírez, David N. Whiteman, Igor Veselovskii, Richard Ferrare, Gloria Titos, María José Granados-Muñoz, Guadalupe Sánchez-Hernández, and Francisco Navas-Guzmán
Atmos. Chem. Phys., 21, 12021–12048,Short summary
This paper shows how aerosol hygroscopicity enhances the vertical profile of aerosol backscattering and extinction. The study is possible thanks to the large set of remote sensing instruments and focuses on the the Baltimore–Washington DC metropolitan area during hot and humid summer days with very relevant anthropogenic emission aerosol sources. The results illustrate how the combination of aerosol emissions and meteorological conditions ultimately alters the aerosol radiative forcing.
Paraskevi Georgakaki, Aikaterini Bougiatioti, Jörg Wieder, Claudia Mignani, Fabiola Ramelli, Zamin A. Kanji, Jan Henneberger, Maxime Hervo, Alexis Berne, Ulrike Lohmann, and Athanasios Nenes
Atmos. Chem. Phys., 21, 10993–11012,Short summary
Aerosol and cloud observations coupled with a droplet activation parameterization was used to investigate the aerosol–cloud droplet link in alpine mixed-phase clouds. Predicted droplet number, Nd, agrees with observations and never exceeds a characteristic “limiting droplet number”, Ndlim, which depends solely on σw. Nd becomes velocity limited when it is within 50 % of Ndlim. Identifying when dynamical changes control Nd variability is central for understanding aerosol–cloud interactions.
Konstantin Baibakov, Samuel LeBlanc, Keyvan Ranjbar, Norman T. O'Neill, Mengistu Wolde, Jens Redemann, Kristina Pistone, Shao-Meng Li, John Liggio, Katherine Hayden, Tak W. Chan, Michael J. Wheeler, Leonid Nichman, Connor Flynn, and Roy Johnson
Atmos. Chem. Phys., 21, 10671–10687,Short summary
We find that the airborne measurements of the vertical extinction due to aerosols (aerosol optical depth, AOD) obtained in the Athabasca Oil Sands Region (AOSR) can significantly exceed ground-based values. This can have an effect on estimating the AOSR radiative impact and is relevant to satellite validation based on ground-based measurements. We also show that the AOD can marginally increase as the plumes are being transported away from the source and the new particles are being formed.
William G. K. McLean, Guangliang Fu, Sharon P. Burton, and Otto P. Hasekamp
Atmos. Meas. Tech., 14, 4755–4771,Short summary
In this study, we present results from aerosol retrievals using both synthetic and real lidar datasets, including measurements from the ACEPOL (Aerosol Characterization from Polarimeter and Lidar) campaign, a combined initiative between NASA and SRON (the Netherlands Institute for Space Research). Aerosol microphysical retrievals were performed using the High Spectral Resolution Lidar-2 (HSRL-2) setup, alongside several others, with the ACEPOL retrievals also compared to polarimeter retrievals.
Georgia Sotiropoulou, Luisa Ickes, Athanasios Nenes, and Annica M. L. Ekman
Atmos. Chem. Phys., 21, 9741–9760,Short summary
Mixed-phase clouds are a large source of uncertainty in projections of the Arctic climate. This is partly due to the poor representation of the cloud ice formation processes. Implementing a parameterization for ice multiplication due to mechanical breakup upon collision of two ice particles in a high-resolution model improves cloud ice phase representation; however, cloud liquid remains overestimated.
Kristina Pistone, Paquita Zuidema, Robert Wood, Michael Diamond, Arlindo M. da Silva, Gonzalo Ferrada, Pablo E. Saide, Rei Ueyama, Ju-Mee Ryoo, Leonhard Pfister, James Podolske, David Noone, Ryan Bennett, Eric Stith, Gregory Carmichael, Jens Redemann, Connor Flynn, Samuel LeBlanc, Michal Segal-Rozenhaimer, and Yohei Shinozuka
Atmos. Chem. Phys., 21, 9643–9668,Short summary
Using aircraft-based measurements off the Atlantic coast of Africa, we found the springtime smoke plume was strongly correlated with the amount of water vapor in the atmosphere (more smoke indicated more humidity). We see the same general feature in satellite-assimilated and free-running models. Our analysis suggests this relationship is not caused by the burning but originates due to coincident continental meteorology plus fires. This air is transported over the ocean without further mixing.
Meng Gao, Bryan A. Franz, Kirk Knobelspiesse, Peng-Wang Zhai, Vanderlei Martins, Sharon Burton, Brian Cairns, Richard Ferrare, Joel Gales, Otto Hasekamp, Yongxiang Hu, Amir Ibrahim, Brent McBride, Anin Puthukkudy, P. Jeremy Werdell, and Xiaoguang Xu
Atmos. Meas. Tech., 14, 4083–4110,Short summary
Multi-angle polarimetric measurements can retrieve accurate aerosol properties over complex atmosphere and ocean systems; however, most retrieval algorithms require high computational costs. We propose a deep neural network (NN) forward model to represent the radiative transfer simulation of coupled atmosphere and ocean systems and then conduct simultaneous aerosol and ocean color retrievals on AirHARP measurements. The computational acceleration is 103 times with CPU or 104 times with GPU.
Nick Schutgens, Oleg Dubovik, Otto Hasekamp, Omar Torres, Hiren Jethva, Peter J. T. Leonard, Pavel Litvinov, Jens Redemann, Yohei Shinozuka, Gerrit de Leeuw, Stefan Kinne, Thomas Popp, Michael Schulz, and Philip Stier
Atmos. Chem. Phys., 21, 6895–6917,Short summary
Absorptive aerosol has a potentially large impact on climate change. We evaluate and intercompare four global satellite datasets of absorptive aerosol optical depth (AAOD) and single-scattering albedo (SSA). We show that these datasets show reasonable correlations with the AErosol RObotic NETwork (AERONET) reference, although significant biases remain. In a follow-up paper we show that these observations nevertheless can be used for model evaluation.
Athanasios Nenes, Spyros N. Pandis, Maria Kanakidou, Armistead G. Russell, Shaojie Song, Petros Vasilakos, and Rodney J. Weber
Atmos. Chem. Phys., 21, 6023–6033,Short summary
Ecosystems and air quality are affected by the dry deposition of inorganic reactive nitrogen (Nr, the sum of ammonium and nitrate). Its large variability is driven by the large difference in deposition velocity of N when in the gas or particle phase. Here we show that aerosol liquid water and acidity, by affecting gas–particle partitioning, modulate the dry deposition velocity of NH3, HNO3, and Nr worldwide. These effects explain the rapid accumulation of nitrate aerosol during haze events.
Andrew M. Dzambo, Tristan L'Ecuyer, Kenneth Sinclair, Bastiaan van Diedenhoven, Siddhant Gupta, Greg McFarquhar, Joseph R. O'Brien, Brian Cairns, Andrzej P. Wasilewski, and Mikhail Alexandrov
Atmos. Chem. Phys., 21, 5513–5532,Short summary
This work highlights a new algorithm using data collected from the 2016–2018 NASA ORACLES field campaign. This algorithm synthesizes cloud and rain measurements to attain estimates of cloud and precipitation properties over the southeast Atlantic Ocean. Estimates produced by this algorithm compare well against in situ estimates. Increased rain fractions and rain rates are found in regions of atmospheric instability. This dataset can be used to explore aerosol–cloud–precipitation interactions.
Siddhant Gupta, Greg M. McFarquhar, Joseph R. O'Brien, David J. Delene, Michael R. Poellot, Amie Dobracki, James R. Podolske, Jens Redemann, Samuel E. LeBlanc, Michal Segal-Rozenhaimer, and Kristina Pistone
Atmos. Chem. Phys., 21, 4615–4635,Short summary
Observations from the 2016 NASA ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) field campaign examine how biomass burning aerosols from southern Africa affect marine stratocumulus cloud decks over the Southeast Atlantic. Instances of contact and separation between aerosols and clouds are examined to quantify the impact of aerosol mixing into cloud top on cloud drop numbers and sizes. This information is needed for improving Earth system models and satellite retrievals.
Yilin Chen, Huizhong Shen, Jennifer Kaiser, Yongtao Hu, Shannon L. Capps, Shunliu Zhao, Amir Hakami, Jhih-Shyang Shih, Gertrude K. Pavur, Matthew D. Turner, Daven K. Henze, Jaroslav Resler, Athanasios Nenes, Sergey L. Napelenok, Jesse O. Bash, Kathleen M. Fahey, Gregory R. Carmichael, Tianfeng Chai, Lieven Clarisse, Pierre-François Coheur, Martin Van Damme, and Armistead G. Russell
Atmos. Chem. Phys., 21, 2067–2082,Short summary
Ammonia (NH3) emissions can exert adverse impacts on air quality and ecosystem well-being. NH3 emission inventories are viewed as highly uncertain. Here we optimize the NH3 emission estimates in the US using an air quality model and NH3 measurements from the IASI satellite instruments. The optimized NH3 emissions are much higher than the National Emissions Inventory estimates in April. The optimized NH3 emissions improved model performance when evaluated against independent observation.
Jens Redemann, Robert Wood, Paquita Zuidema, Sarah J. Doherty, Bernadette Luna, Samuel E. LeBlanc, Michael S. Diamond, Yohei Shinozuka, Ian Y. Chang, Rei Ueyama, Leonhard Pfister, Ju-Mee Ryoo, Amie N. Dobracki, Arlindo M. da Silva, Karla M. Longo, Meloë S. Kacenelenbogen, Connor J. Flynn, Kristina Pistone, Nichola M. Knox, Stuart J. Piketh, James M. Haywood, Paola Formenti, Marc Mallet, Philip Stier, Andrew S. Ackerman, Susanne E. Bauer, Ann M. Fridlind, Gregory R. Carmichael, Pablo E. Saide, Gonzalo A. Ferrada, Steven G. Howell, Steffen Freitag, Brian Cairns, Brent N. Holben, Kirk D. Knobelspiesse, Simone Tanelli, Tristan S. L'Ecuyer, Andrew M. Dzambo, Ousmane O. Sy, Greg M. McFarquhar, Michael R. Poellot, Siddhant Gupta, Joseph R. O'Brien, Athanasios Nenes, Mary Kacarab, Jenny P. S. Wong, Jennifer D. Small-Griswold, Kenneth L. Thornhill, David Noone, James R. Podolske, K. Sebastian Schmidt, Peter Pilewskie, Hong Chen, Sabrina P. Cochrane, Arthur J. Sedlacek, Timothy J. Lang, Eric Stith, Michal Segal-Rozenhaimer, Richard A. Ferrare, Sharon P. Burton, Chris A. Hostetler, David J. Diner, Felix C. Seidel, Steven E. Platnick, Jeffrey S. Myers, Kerry G. Meyer, Douglas A. Spangenberg, Hal Maring, and Lan Gao
Atmos. Chem. Phys., 21, 1507–1563,Short summary
Southern Africa produces significant biomass burning emissions whose impacts on regional and global climate are poorly understood. ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) is a 5-year NASA investigation designed to study the key processes that determine these climate impacts. The main purpose of this paper is to familiarize the broader scientific community with the ORACLES project, the dataset it produced, and the most important initial findings.
Sabrina P. Cochrane, K. Sebastian Schmidt, Hong Chen, Peter Pilewskie, Scott Kittelman, Jens Redemann, Samuel LeBlanc, Kristina Pistone, Meloë Kacenelenbogen, Michal Segal Rozenhaimer, Yohei Shinozuka, Connor Flynn, Amie Dobracki, Paquita Zuidema, Steven Howell, Steffen Freitag, and Sarah Doherty
Atmos. Meas. Tech., 14, 567–593,Short summary
Based on observations from the 2016 and 2017 field campaigns of ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS), this work establishes an observationally driven link from mid-visible aerosol optical depth (AOD) and other scene parameters to broadband shortwave irradiance (and by extension the direct aerosol radiative effect, DARE). The majority of the case-to-case DARE variability within the ORACLES dataset is attributable to the dependence on AOD and scene albedo.
Jim M. Haywood, Steven J. Abel, Paul A. Barrett, Nicolas Bellouin, Alan Blyth, Keith N. Bower, Melissa Brooks, Ken Carslaw, Haochi Che, Hugh Coe, Michael I. Cotterell, Ian Crawford, Zhiqiang Cui, Nicholas Davies, Beth Dingley, Paul Field, Paola Formenti, Hamish Gordon, Martin de Graaf, Ross Herbert, Ben Johnson, Anthony C. Jones, Justin M. Langridge, Florent Malavelle, Daniel G. Partridge, Fanny Peers, Jens Redemann, Philip Stier, Kate Szpek, Jonathan W. Taylor, Duncan Watson-Parris, Robert Wood, Huihui Wu, and Paquita Zuidema
Atmos. Chem. Phys., 21, 1049–1084,Short summary
Every year, the seasonal cycle of biomass burning from agricultural practices in Africa creates a huge plume of smoke that travels many thousands of kilometres over the Atlantic Ocean. This study provides an overview of a measurement campaign called the cloud–aerosol–radiation interaction and forcing for year 2017 (CLARIFY-2017) and documents the rationale, deployment strategy, observations, and key results from the campaign which utilized the heavily equipped FAAM atmospheric research aircraft.
Stylianos Kakavas, David Patoulias, Maria Zakoura, Athanasios Nenes, and Spyros N. Pandis
Atmos. Chem. Phys., 21, 799–811,Short summary
The dependence of aerosol acidity on particle size, location, and altitude over Europe during a summertime period is investigated. Differences of up to 1–4 pH units are predicted between sub- and supermicron particles in northern and southern Europe. Particles of all sizes become increasingly acidic with altitude (0.5–2.5 pH units decrease over 2.5 km). The size-dependent pH differences carry important implications for pH-sensitive processes in the aerosol.
Georgia Sotiropoulou, Étienne Vignon, Gillian Young, Hugh Morrison, Sebastian J. O'Shea, Thomas Lachlan-Cope, Alexis Berne, and Athanasios Nenes
Atmos. Chem. Phys., 21, 755–771,Short summary
Summer clouds have a significant impact on the radiation budget of the Antarctic surface and thus on ice-shelf melting. However, these are poorly represented in climate models due to errors in their microphysical structure, including the number of ice crystals that they contain. We show that breakup from ice particle collisions can substantially magnify the ice crystal number concentration with significant implications for surface radiation. This process is currently missing in climate models.
Johannes Quaas, Antti Arola, Brian Cairns, Matthew Christensen, Hartwig Deneke, Annica M. L. Ekman, Graham Feingold, Ann Fridlind, Edward Gryspeerdt, Otto Hasekamp, Zhanqing Li, Antti Lipponen, Po-Lun Ma, Johannes Mülmenstädt, Athanasios Nenes, Joyce E. Penner, Daniel Rosenfeld, Roland Schrödner, Kenneth Sinclair, Odran Sourdeval, Philip Stier, Matthias Tesche, Bastiaan van Diedenhoven, and Manfred Wendisch
Atmos. Chem. Phys., 20, 15079–15099,Short summary
Anthropogenic pollution particles – aerosols – serve as cloud condensation nuclei and thus increase cloud droplet concentration and the clouds' reflection of sunlight (a cooling effect on climate). This Twomey effect is poorly constrained by models and requires satellite data for better quantification. The review summarizes the challenges in properly doing so and outlines avenues for progress towards a better use of aerosol retrievals and better retrievals of droplet concentrations.
Ari Laaksonen, Jussi Malila, and Athanasios Nenes
Atmos. Chem. Phys., 20, 13579–13589,Short summary
Aerosol particles containing black carbon are ubiquitous in the atmosphere and originate from combustion processes. We examine their capability to act as condensation centers for water vapor. We make use of published experimental data sets for different types of black carbon particles, ranging from very pure particles to particles that contain both black carbon and water soluble organic matter, and we show that a recently developed theory reproduces most of the experimental results.
Lanxiadi Chen, Chao Peng, Wenjun Gu, Hanjing Fu, Xing Jian, Huanhuan Zhang, Guohua Zhang, Jianxi Zhu, Xinming Wang, and Mingjin Tang
Atmos. Chem. Phys., 20, 13611–13626,Short summary
We investigated hygroscopic properties of a number of mineral dust particles in a quantitative manner, via measuring the sample mass at different relative humidities. The robust and comprehensive data obtained would significantly improve our knowledge of hygroscopicity of mineral dust and its impacts on atmospheric chemistry and climate.
Marc Mallet, Fabien Solmon, Pierre Nabat, Nellie Elguindi, Fabien Waquet, Dominique Bouniol, Andrew Mark Sayer, Kerry Meyer, Romain Roehrig, Martine Michou, Paquita Zuidema, Cyrille Flamant, Jens Redemann, and Paola Formenti
Atmos. Chem. Phys., 20, 13191–13216,Short summary
This paper presents numerical simulations using two regional climate models to study the impact of biomass fire plumes from central Africa on the radiative balance of this region. The results indicate that biomass fires can either warm the regional climate when they are located above low clouds or cool it when they are located above land. They can also alter sea and land surface temperatures by decreasing solar radiation at the surface. Finally, they can also modify the atmospheric dynamics.
Aikaterini Bougiatioti, Athanasios Nenes, Jack J. Lin, Charles A. Brock, Joost A. de Gouw, Jin Liao, Ann M. Middlebrook, and André Welti
Atmos. Chem. Phys., 20, 12163–12176,Short summary
The number concentration of droplets in clouds in the summertime in the southeastern United States is influenced by aerosol variations but limited by the strong competition for supersaturated water vapor. Concurrent variations in vertical velocity magnify the response of cloud droplet number to aerosol increases by up to a factor of 5. Omitting the covariance of vertical velocity with aerosol number may therefore bias estimates of the cloud albedo effect from aerosols.
Yohei Shinozuka, Pablo E. Saide, Gonzalo A. Ferrada, Sharon P. Burton, Richard Ferrare, Sarah J. Doherty, Hamish Gordon, Karla Longo, Marc Mallet, Yan Feng, Qiaoqiao Wang, Yafang Cheng, Amie Dobracki, Steffen Freitag, Steven G. Howell, Samuel LeBlanc, Connor Flynn, Michal Segal-Rosenhaimer, Kristina Pistone, James R. Podolske, Eric J. Stith, Joseph Ryan Bennett, Gregory R. Carmichael, Arlindo da Silva, Ravi Govindaraju, Ruby Leung, Yang Zhang, Leonhard Pfister, Ju-Mee Ryoo, Jens Redemann, Robert Wood, and Paquita Zuidema
Atmos. Chem. Phys., 20, 11491–11526,Short summary
In the southeast Atlantic, well-defined smoke plumes from Africa advect over marine boundary layer cloud decks; both are most extensive around September, when most of the smoke resides in the free troposphere. A framework is put forth for evaluating the performance of a range of global and regional atmospheric composition models against observations made during the NASA ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) airborne mission in September 2016.
Anin Puthukkudy, J. Vanderlei Martins, Lorraine A. Remer, Xiaoguang Xu, Oleg Dubovik, Pavel Litvinov, Brent McBride, Sharon Burton, and Henrique M. J. Barbosa
Atmos. Meas. Tech., 13, 5207–5236,Short summary
In this work, we report the demonstration and validation of the aerosol properties retrieved using AirHARP and GRASP for data from the NASA ACEPOL campaign 2017. These results serve as a proxy for the scale and detail of aerosol retrievals that are anticipated from future space mission data, as HARP CubeSat (mission begins 2020) and HARP2 (aboard the NASA PACE mission with the launch in 2023) are near duplicates of AirHARP and are expected to provide the same level of aerosol characterization.
Yohei Shinozuka, Meloë S. Kacenelenbogen, Sharon P. Burton, Steven G. Howell, Paquita Zuidema, Richard A. Ferrare, Samuel E. LeBlanc, Kristina Pistone, Stephen Broccardo, Jens Redemann, K. Sebastian Schmidt, Sabrina P. Cochrane, Marta Fenn, Steffen Freitag, Amie Dobracki, Michal Segal-Rosenheimer, and Connor J. Flynn
Atmos. Chem. Phys., 20, 11275–11285,Short summary
To help satellite retrieval of aerosols and studies of their radiative effects, we demonstrate that daytime aerosol optical depth over low-level clouds is similar to that in neighboring clear skies at the same heights. Based on recent airborne lidar and sun photometer observations above the southeast Atlantic, the mean AOD difference at 532 nm is between 0 and -0.01, when comparing the cloudy and clear sides of cloud edges, with each up to 20 km wide.
Adeyemi A. Adebiyi, Paquita Zuidema, Ian Chang, Sharon P. Burton, and Brian Cairns
Atmos. Chem. Phys., 20, 11025–11043,Short summary
Over the southeast Atlantic, interactions between the low-level clouds and the overlying smoke aerosols have previously been highlighted, but no study has yet focused on the presence of the mid-level clouds that complicate the aerosol–cloud interactions. Here we show that these optically thin super-cooled mid-level clouds are relatively common, and they frequently occur at the top of the smoke layer between August and October with significant radiative impacts on the low-level clouds.
Kirk Knobelspiesse, Henrique M. J. Barbosa, Christine Bradley, Carol Bruegge, Brian Cairns, Gao Chen, Jacek Chowdhary, Anthony Cook, Antonio Di Noia, Bastiaan van Diedenhoven, David J. Diner, Richard Ferrare, Guangliang Fu, Meng Gao, Michael Garay, Johnathan Hair, David Harper, Gerard van Harten, Otto Hasekamp, Mark Helmlinger, Chris Hostetler, Olga Kalashnikova, Andrew Kupchock, Karla Longo De Freitas, Hal Maring, J. Vanderlei Martins, Brent McBride, Matthew McGill, Ken Norlin, Anin Puthukkudy, Brian Rheingans, Jeroen Rietjens, Felix C. Seidel, Arlindo da Silva, Martijn Smit, Snorre Stamnes, Qian Tan, Sebastian Val, Andrzej Wasilewski, Feng Xu, Xiaoguang Xu, and John Yorks
Earth Syst. Sci. Data, 12, 2183–2208,Short summary
The Aerosol Characterization from Polarimeter and Lidar (ACEPOL) field campaign is a resource for the next generation of spaceborne multi-angle polarimeter (MAP) and lidar missions. Conducted in the fall of 2017 from the Armstrong Flight Research Center in Palmdale, California, four MAP instruments and two lidars were flown on the high-altitude ER-2 aircraft over a variety of scene types and ground assets. Data are freely available to the public and useful for algorithm development and testing.
Meng Gao, Peng-Wang Zhai, Bryan A. Franz, Kirk Knobelspiesse, Amir Ibrahim, Brian Cairns, Susanne E. Craig, Guangliang Fu, Otto Hasekamp, Yongxiang Hu, and P. Jeremy Werdell
Atmos. Meas. Tech., 13, 3939–3956,
Ifayoyinsola Ibikunle, Andreas Beyersdorf, Pedro Campuzano-Jost, Chelsea Corr, John D. Crounse, Jack Dibb, Glenn Diskin, Greg Huey, Jose-Luis Jimenez, Michelle J. Kim, Benjamin A. Nault, Eric Scheuer, Alex Teng, Paul O. Wennberg, Bruce Anderson, James Crawford, Rodney Weber, and Athanasios Nenes
Atmos. Chem. Phys. Discuss.,
Publication in ACP not foreseenShort summary
Analysis of observations over South Korea during the NASA/NIER KORUS-AQ field campaign show that aerosol is fairly acidic (mean pH 2.43 ± 0.68). Aerosol formation is always sensitive to HNO3 levels, especially in highly polluted regions, while it is only exclusively sensitive to NH3 in some rural/remote regions. Nitrate levels accumulate because dry deposition velocity is low. HNO3 reductions achieved by NOx controls can be the most effective PM reduction strategy for all conditions observed.
Shunliu Zhao, Matthew G. Russell, Amir Hakami, Shannon L. Capps, Matthew D. Turner, Daven K. Henze, Peter B. Percell, Jaroslav Resler, Huizhong Shen, Armistead G. Russell, Athanasios Nenes, Amanda J. Pappin, Sergey L. Napelenok, Jesse O. Bash, Kathleen M. Fahey, Gregory R. Carmichael, Charles O. Stanier, and Tianfeng Chai
Geosci. Model Dev., 13, 2925–2944,
Daniel J. Miller, Michal Segal-Rozenhaimer, Kirk Knobelspiesse, Jens Redemann, Brian Cairns, Mikhail Alexandrov, Bastiaan van Diedenhoven, and Andrzej Wasilewski
Atmos. Meas. Tech., 13, 3447–3470,Short summary
A neural network (NN) is developed and used to retrieve cloud microphysical properties from multiangular and multispectral polarimetric remote sensing observations. The NN is applied to research scanning polarimeter (RSP) observations obtained during the ORACLES field campaign and compared to other co-located remote sensing retrievals of cloud effective radius and optical thickness. A NN approach can advance more complex iterative search retrieval algorithms by providing a quick initial guess.
David Painemal, Fu-Lung Chang, Richard Ferrare, Sharon Burton, Zhujun Li, William L. Smith Jr., Patrick Minnis, Yan Feng, and Marian Clayton
Atmos. Chem. Phys., 20, 7167–7177,Short summary
Aerosol–cloud interactions (ACIs) are the most uncertain aspect of anthropogenic forcing. Although satellites provide the observational dataset for the global ACI quantification, retrievals are limited to vertically integrated quantities (e.g., aerosol optical depth – AOD), which are typically used as an aerosol proxy. This study demonstrates that matching vertically resolved aerosol from CALIOP at the cloud-layer height with satellite cloud retrievals reduces uncertainties in ACI estimates.
Pablo E. Saide, Meng Gao, Zifeng Lu, Daniel L. Goldberg, David G. Streets, Jung-Hun Woo, Andreas Beyersdorf, Chelsea A. Corr, Kenneth L. Thornhill, Bruce Anderson, Johnathan W. Hair, Amin R. Nehrir, Glenn S. Diskin, Jose L. Jimenez, Benjamin A. Nault, Pedro Campuzano-Jost, Jack Dibb, Eric Heim, Kara D. Lamb, Joshua P. Schwarz, Anne E. Perring, Jhoon Kim, Myungje Choi, Brent Holben, Gabriele Pfister, Alma Hodzic, Gregory R. Carmichael, Louisa Emmons, and James H. Crawford
Atmos. Chem. Phys., 20, 6455–6478,Short summary
Air quality forecasts over the Korean Peninsula captured aerosol optical depth but largely overpredicted surface PM during a Chinese haze transport event. Model deficiency was related to the calculation of optical properties. In order to improve it, aerosol size representation needs to be refined in the calculations, and the representation of aerosol properties, such as size distribution, chemical composition, refractive index, hygroscopicity parameter, and density, needs to be improved.
Sungyeon Choi, Lok N. Lamsal, Melanie Follette-Cook, Joanna Joiner, Nickolay A. Krotkov, William H. Swartz, Kenneth E. Pickering, Christopher P. Loughner, Wyat Appel, Gabriele Pfister, Pablo E. Saide, Ronald C. Cohen, Andrew J. Weinheimer, and Jay R. Herman
Atmos. Meas. Tech., 13, 2523–2546,
Sojin Lee, Chul Han Song, Kyung Man Han, Daven K. Henze, Kyunghwa Lee, Jinhyeok Yu, Jung-Hun Woo, Jia Jung, Yunsoo Choi, Pablo E. Saide, and Gregory R. Carmichael
Geosci. Model Dev. Discuss.,
Revised manuscript not accepted
Havala O. T. Pye, Athanasios Nenes, Becky Alexander, Andrew P. Ault, Mary C. Barth, Simon L. Clegg, Jeffrey L. Collett Jr., Kathleen M. Fahey, Christopher J. Hennigan, Hartmut Herrmann, Maria Kanakidou, James T. Kelly, I-Ting Ku, V. Faye McNeill, Nicole Riemer, Thomas Schaefer, Guoliang Shi, Andreas Tilgner, John T. Walker, Tao Wang, Rodney Weber, Jia Xing, Rahul A. Zaveri, and Andreas Zuend
Atmos. Chem. Phys., 20, 4809–4888,Short summary
Acid rain is recognized for its impacts on human health and ecosystems, and programs to mitigate these effects have had implications for atmospheric acidity. Historical measurements indicate that cloud and fog droplet acidity has changed in recent decades in response to controls on emissions from human activity, while the limited trend data for suspended particles indicate acidity may be relatively constant. This review synthesizes knowledge on the acidity of atmospheric particles and clouds.
Athanasios Nenes, Spyros N. Pandis, Rodney J. Weber, and Armistead Russell
Atmos. Chem. Phys., 20, 3249–3258,Short summary
We show that aerosol acidity (pH) and liquid water content naturally emerge as previously ignored parameters that drive particulate matter formation in the atmosphere, and its sensitivity to emissions of ammonia and nitric acid. The simple framework presented is easily applied to ambient measurements or model output, and it provides the
chemical regimeof PM sensitivity to ammonia and nitric acid availability.
Mary Kacarab, K. Lee Thornhill, Amie Dobracki, Steven G. Howell, Joseph R. O'Brien, Steffen Freitag, Michael R. Poellot, Robert Wood, Paquita Zuidema, Jens Redemann, and Athanasios Nenes
Atmos. Chem. Phys., 20, 3029–3040,Short summary
We find that extensive biomass burning aerosol plumes from southern Africa can profoundly influence clouds in the southeastern Atlantic. Concurrent variations in vertical velocity, however, are found to magnify the relationship between boundary layer aerosol and the cloud droplet number. Neglecting these covariances may strongly bias the sign and magnitude of aerosol impacts on the cloud droplet number.
Arnaldo Negron, Natasha DeLeon-Rodriguez, Samantha M. Waters, Luke D. Ziemba, Bruce Anderson, Michael Bergin, Konstantinos T. Konstantinidis, and Athanasios Nenes
Atmos. Chem. Phys., 20, 1817–1838,Short summary
Airborne biological particles impact human health, cloud formation, and ecosystems, but few techniques are available to characterize their atmospheric abundance. Combining a newly developed high-volume sampling/flow cytometry technique together with an laser-induced fluorescence instrument, we detect a highly dynamic bioaerosol community over urban Atlanta, composed of pollen, fungi, and bacteria with low and high nucleic acid content.
Samuel E. LeBlanc, Jens Redemann, Connor Flynn, Kristina Pistone, Meloë Kacenelenbogen, Michal Segal-Rosenheimer, Yohei Shinozuka, Stephen Dunagan, Robert P. Dahlgren, Kerry Meyer, James Podolske, Steven G. Howell, Steffen Freitag, Jennifer Small-Griswold, Brent Holben, Michael Diamond, Robert Wood, Paola Formenti, Stuart Piketh, Gillian Maggs-Kölling, Monja Gerber, and Andreas Namwoonde
Atmos. Chem. Phys., 20, 1565–1590,Short summary
The southeast Atlantic during August–October experiences layers of smoke from biomass burning over marine stratocumulus clouds. Here we present the light attenuation of the smoke and its dependence in the spatial, vertical, and spectral domain through direct measurements from an airborne platform during September 2016. From our observations of this climatically important smoke, we found an average aerosol optical depth of 0.32 at 500 nm, slightly lower than comparative satellite measurements.
Guangliang Fu, Otto Hasekamp, Jeroen Rietjens, Martijn Smit, Antonio Di Noia, Brian Cairns, Andrzej Wasilewski, David Diner, Felix Seidel, Feng Xu, Kirk Knobelspiesse, Meng Gao, Arlindo da Silva, Sharon Burton, Chris Hostetler, John Hair, and Richard Ferrare
Atmos. Meas. Tech., 13, 553–573,Short summary
In this paper, we present aerosol retrieval results from the ACEPOL (Aerosol Characterization from Polarimeter and Lidar) campaign, which was a joint initiative between NASA and SRON (the Netherlands Institute for Space Research). We perform aerosol retrievals from different multi-angle polarimeters employed during the ACEPOL campaign and evaluate them against ground-based AERONET measurements and High Spectral Resolution Lidar-2 (HSRL-2) measurements.
Georgia Sotiropoulou, Sylvia Sullivan, Julien Savre, Gary Lloyd, Thomas Lachlan-Cope, Annica M. L. Ekman, and Athanasios Nenes
Atmos. Chem. Phys., 20, 1301–1316,Short summary
Arctic clouds constitute a large source of uncertainty in predictions of future climate. Observations indicate that the number concentration of cloud ice crystals exceeds the concentration of aerosols that can act as ice-nucleating particles (INPs). We show that ice multiplication due to mechanical break-up upon collisions between the few primary ice crystals (formed from INPs) can explain the discrepancy. Including a description of the process in climate models can improve cloud representation.
Wenbo Sun, Yongxiang Hu, Rosemary R. Baize, Gorden Videen, Sungsoo S. Kim, Young-Jun Choi, Kyungin Kang, Chae Kyung Sim, Minsup Jeong, Ali Omar, Snorre A. Stamnes, David G. MacDonnell, and Evgenij Zubko
Atmos. Chem. Phys., 19, 15583–15586,Short summary
Dusts have a significant impact on climate and environment. Detecting dust using satellite instruments is generally conducted by measuring at multiple observation angles due to the uncertainty of the surface reflection. This report shows that the degree of polarization of reflected light can be used for retrieving the optical depth of dust at backscatter angles only, regardless of surface conditions. This simple method is suitable for surveying dust aerosols over oceans with low-cost satellites.
Sabrina P. Cochrane, K. Sebastian Schmidt, Hong Chen, Peter Pilewskie, Scott Kittelman, Jens Redemann, Samuel LeBlanc, Kristina Pistone, Meloë Kacenelenbogen, Michal Segal Rozenhaimer, Yohei Shinozuka, Connor Flynn, Steven Platnick, Kerry Meyer, Rich Ferrare, Sharon Burton, Chris Hostetler, Steven Howell, Steffen Freitag, Amie Dobracki, and Sarah Doherty
Atmos. Meas. Tech., 12, 6505–6528,Short summary
For two cases from the NASA ORACLES experiments, we retrieve aerosol and cloud properties and calculate a direct aerosol radiative effect (DARE). We investigate the relationship between DARE and the cloud albedo by specifying the albedo for which DARE transitions from a cooling to warming radiative effect. Our new aerosol retrieval algorithm is successful despite complexities associated with scenes that contain aerosols above clouds and decreases the uncertainty on retrieved aerosol parameters.
Michael A. Battaglia Jr., Rodney J. Weber, Athanasios Nenes, and Christopher J. Hennigan
Atmos. Chem. Phys., 19, 14607–14620,Short summary
The effects of water-soluble organic carbon (WSOC) on aerosol pH were characterized for aqueous-phase particles containing a mixture of inorganics and organics. The ISORROPIA-II and E-AIM models were used in conjunction with AIOMFAC to quantify the effect of organics on aerosol pH through (1) changes to the aerosol liquid water content and (2) changes to the hydrogen ion activity coefficient. The study included both organic acids and nonacids, at RH levels ranging from 70 to 90 %.
Eleni Marinou, Matthias Tesche, Athanasios Nenes, Albert Ansmann, Jann Schrod, Dimitra Mamali, Alexandra Tsekeri, Michael Pikridas, Holger Baars, Ronny Engelmann, Kalliopi-Artemis Voudouri, Stavros Solomos, Jean Sciare, Silke Groß, Florian Ewald, and Vassilis Amiridis
Atmos. Chem. Phys., 19, 11315–11342,Short summary
We assess the feasibility of ground-based and spaceborne lidars to retrieve profiles of cloud-relevant aerosol concentrations and ice-nucleating particles. The retrieved profiles are in good agreement with airborne in situ measurements. Our methodology will be applied to satellite observations in the future so as to provide a global 3D product of cloud-relevant properties.
Myungje Choi, Hyunkwang Lim, Jhoon Kim, Seoyoung Lee, Thomas F. Eck, Brent N. Holben, Michael J. Garay, Edward J. Hyer, Pablo E. Saide, and Hongqing Liu
Atmos. Meas. Tech., 12, 4619–4641,Short summary
Satellite-based aerosol optical depth (AOD) products have been improved continuously and available from multiple low Earth orbit sensors, such as MODIS, MISR, and VIIRS, and geostationary sensors, such as GOCI and AHI, over East Asia. These multi-satellite AOD products are validated, intercompared, analyzed, and integrated to understand different characteristics, such as quality and spatio-temporal coverage, focused on several aerosol transportation cases during the 2016 KORUS-AQ campaign.
Matthias Tesche, Alexei Kolgotin, Moritz Haarig, Sharon P. Burton, Richard A. Ferrare, Chris A. Hostetler, and Detlef Müller
Atmos. Meas. Tech., 12, 4421–4437,Short summary
Today, few lidar are capable of triple-wavelength particle linear depolarization ratio (PLDR) measurements. This study is the first systematic investigation of the effect of different choices of PLDR input on the inversion of lidar measurements of mineral dust and dusty mixtures using light scattering by randomly oriented spheroids. We provide recommendations of the most suitable input parameters for use with the applied methodology, based on a relational assessment of the inversion output.
Diep Vu, Shaokai Gao, Tyler Berte, Mary Kacarab, Qi Yao, Kambiz Vafai, and Akua Asa-Awuku
Atmos. Meas. Tech., 12, 4277–4289,Short summary
Aerosol–cloud interactions contribute the greatest uncertainty to cloud formation. Aerosol composition is complex and can change quickly in the atmosphere. In this work, we recreate a transition in aerosol mixing state in the laboratory, which (to date) has only been observed in the ambient state. We then report the subsequent changes on cloud condensation nuclei (CCN) activation.
Kristina Pistone, Jens Redemann, Sarah Doherty, Paquita Zuidema, Sharon Burton, Brian Cairns, Sabrina Cochrane, Richard Ferrare, Connor Flynn, Steffen Freitag, Steven G. Howell, Meloë Kacenelenbogen, Samuel LeBlanc, Xu Liu, K. Sebastian Schmidt, Arthur J. Sedlacek III, Michal Segal-Rozenhaimer, Yohei Shinozuka, Snorre Stamnes, Bastiaan van Diedenhoven, Gerard Van Harten, and Feng Xu
Atmos. Chem. Phys., 19, 9181–9208,Short summary
Understanding how smoke particles interact with sunlight is important in calculating their effects on climate, since some smoke is more scattering (cooling) and some is more absorbing (heating). Knowing this proportion is important for both satellite observations and climate models. We measured smoke properties in a recent aircraft-based field campaign off the west coast of Africa and present a comparison of these properties as measured using the six different, independent techniques available.
Meng Gao, Peng-Wang Zhai, Bryan A. Franz, Yongxiang Hu, Kirk Knobelspiesse, P. Jeremy Werdell, Amir Ibrahim, Brian Cairns, and Alison Chase
Atmos. Meas. Tech., 12, 3921–3941,
George S. Fanourgakis, Maria Kanakidou, Athanasios Nenes, Susanne E. Bauer, Tommi Bergman, Ken S. Carslaw, Alf Grini, Douglas S. Hamilton, Jill S. Johnson, Vlassis A. Karydis, Alf Kirkevåg, John K. Kodros, Ulrike Lohmann, Gan Luo, Risto Makkonen, Hitoshi Matsui, David Neubauer, Jeffrey R. Pierce, Julia Schmale, Philip Stier, Kostas Tsigaridis, Twan van Noije, Hailong Wang, Duncan Watson-Parris, Daniel M. Westervelt, Yang Yang, Masaru Yoshioka, Nikos Daskalakis, Stefano Decesari, Martin Gysel-Beer, Nikos Kalivitis, Xiaohong Liu, Natalie M. Mahowald, Stelios Myriokefalitakis, Roland Schrödner, Maria Sfakianaki, Alexandra P. Tsimpidi, Mingxuan Wu, and Fangqun Yu
Atmos. Chem. Phys., 19, 8591–8617,Short summary
Effects of aerosols on clouds are important for climate studies but are among the largest uncertainties in climate projections. This study evaluates the skill of global models to simulate aerosol, cloud condensation nuclei (CCN) and cloud droplet number concentrations (CDNCs). Model results show reduced spread in CDNC compared to CCN due to the negative correlation between the sensitivities of CDNC to aerosol number concentration (air pollution) and updraft velocity (atmospheric dynamics).
Andrew M. Sayer, N. Christina Hsu, Jaehwa Lee, Woogyung V. Kim, Sharon Burton, Marta A. Fenn, Richard A. Ferrare, Meloë Kacenelenbogen, Samuel LeBlanc, Kristina Pistone, Jens Redemann, Michal Segal-Rozenhaimer, Yohei Shinozuka, and Si-Chee Tsay
Atmos. Meas. Tech., 12, 3595–3627,Short summary
Aerosols are small particles in the atmosphere such as dust or smoke. They are routinely monitored by satellites due to their importance for climate and air quality. However aerosols above clouds are more difficult to monitor. This study describes an improvement to a technique to monitor light-absorbing aerosols above clouds from four Earth-orbiting satellite instruments. The improved method is evaluated using data from the ORACLES field campaign, which measured these aerosols from aircraft.
Jenny P. S. Wong, Maria Tsagkaraki, Irini Tsiodra, Nikolaos Mihalopoulos, Kalliopi Violaki, Maria Kanakidou, Jean Sciare, Athanasios Nenes, and Rodney J. Weber
Atmos. Chem. Phys., 19, 7319–7334,Short summary
Biomass burning is a major source of light-absorbing organic species in atmospheric aerosols, and it can play an important role in climate and atmospheric chemistry. Through a combination of laboratory experiments and field observations, this work demonstrated that the light absorption properties of aged biomass burning organic aerosols are dominated by high-molecular-weight compounds. In addition, we found that total hydrated sugars may be a robust tracer for aged biomass burning aerosols.
Panayiotis Kalkavouras, Aikaterini Bougiatioti, Nikos Kalivitis, Iasonas Stavroulas, Maria Tombrou, Athanasios Nenes, and Nikolaos Mihalopoulos
Atmos. Chem. Phys., 19, 6185–6203,Short summary
We study how new particle formation (NPF) events affect clouds throughout the year at a ground site in the E Mediterranean. Using a new tools and evaluation metrics, NPF is found to affect only evening and nocturnal clouds by modestly increasing droplet number by 7 to 12 %. A conventional analysis based on CCN concentration at prescribed supersaturation levels or aerosol size can considerably bias the perceived influence of NPF events on regional clouds, the hydrological cycle, and climate.
Meloë S. Kacenelenbogen, Mark A. Vaughan, Jens Redemann, Stuart A. Young, Zhaoyan Liu, Yongxiang Hu, Ali H. Omar, Samuel LeBlanc, Yohei Shinozuka, John Livingston, Qin Zhang, and Kathleen A. Powell
Atmos. Chem. Phys., 19, 4933–4962,Short summary
Significant efforts are required to estimate the direct radiative effects of aerosols above clouds (DAREcloudy). We have used a combination of passive and active A-Train satellite sensors and derive mainly positive global and regional DAREcloudy values (e.g., global seasonal values between 0.13 and 0.26 W m-2). Despite differences in methods and sensors, the DAREcloudy values in this study are generally higher than previously reported. We discuss the primary reasons for these higher estimates.
Marc Mallet, Pierre Nabat, Paquita Zuidema, Jens Redemann, Andrew Mark Sayer, Martin Stengel, Sebastian Schmidt, Sabrina Cochrane, Sharon Burton, Richard Ferrare, Kerry Meyer, Pablo Saide, Hiren Jethva, Omar Torres, Robert Wood, David Saint Martin, Romain Roehrig, Christina Hsu, and Paola Formenti
Atmos. Chem. Phys., 19, 4963–4990,Short summary
The model is able to represent LWP but not the LCF. AOD is consistent over the continent but also over ocean (ACAOD). Differences are observed in SSA due to the absence of internal mixing in ALADIN-Climate. A significant regional gradient of the forcing at TOA is observed. An intense positive forcing is simulated over Gabon. Results highlight the significant effect of enhanced moisture on BBA extinction. The surface dimming modifies the energy budget.
David Painemal, Marian Clayton, Richard Ferrare, Sharon Burton, Damien Josset, and Mark Vaughan
Atmos. Meas. Tech., 12, 2201–2217,Short summary
We present 1 year of a new CALIOP-based aerosol extinction coefficient and lidar ratio over the ocean, with the goal of providing a flexible dataset for climate research as well as independent retrievals that can be helpful for refining CALIPSO Science Team algorithms. The retrievals are derived by constraining the lidar equation with an aerosol optical depth estimated from cross-calibrated CALIOP and CloudSat surface echos.
Nønne L. Prisle, Jack J. Lin, Sara Purdue, Haisheng Lin, J. Carson Meredith, and Athanasios Nenes
Atmos. Chem. Phys., 19, 4741–4761,Short summary
We measure surface activity and cloud-forming potential of pollenkitt, an organic mixture coating pollen grains. Cloud droplet formation is affected through both surface tension and bulk depletion, with a consistent particle size-dependent signature. We observe nonideal solution effects in pollenkitt mixtures with ammonium sulfate salt. Our results suggest sensitivity of general water interactions, including cloud formation by pollen and their fragments, to both atmospheric humidity and aging.
Daniel L. Goldberg, Pablo E. Saide, Lok N. Lamsal, Benjamin de Foy, Zifeng Lu, Jung-Hun Woo, Younha Kim, Jinseok Kim, Meng Gao, Gregory Carmichael, and David G. Streets
Atmos. Chem. Phys., 19, 1801–1818,Short summary
Using satellite data, we are able to estimate the emissions of NOx (NOx=NO+NO2), a toxic group of air pollutants, in the Seoul metropolitan area. We first develop an enhanced satellite product that better observes NO2 in urban regions. Using this new product, we derive NOx emissions to be twice as large as the emissions reported by the South Korean government. The implication is that the measures taken to reduce NOx emissions in South Korea have not been as effective as regulators have thought.
Mayra I. Oyola, James R. Campbell, Peng Xian, Anthony Bucholtz, Richard A. Ferrare, Sharon P. Burton, Olga Kalashnikova, Benjamin C. Ruston, and Simone Lolli
Atmos. Chem. Phys., 19, 205–218,Short summary
We conceptualized the aerosol radiative impact of an inline aerosol analysis field coupled with a global meteorological forecast system utilizing NAAPS and NAVGEM analysis and surface albedo fields. Model simulations were compared with in situ validation data collected during the NASA 2013 SEAC4RS experiment. Instantaneous heating rates peaked around 7 K day-1 in the lower part of the troposphere, while the HSRL profiles resulted in values of up to 18 K day-1 in the in the mid-troposphere.
Mark Vaughan, Anne Garnier, Damien Josset, Melody Avery, Kam-Pui Lee, Zhaoyan Liu, William Hunt, Jacques Pelon, Yongxiang Hu, Sharon Burton, Johnathan Hair, Jason L. Tackett, Brian Getzewich, Jayanta Kar, and Sharon Rodier
Atmos. Meas. Tech., 12, 51–82,Short summary
The version 4 (V4) release of the CALIPSO data products includes substantial improvements to the calibration of the CALIOP 1064 nm channel. In this paper we review the fundamentals of 1064 nm lidar calibration, explain the motivations for the changes made to the algorithm, and describe the mechanics of the V4 calibration technique. Internal consistency checks and comparisons to collocated high spectral resolution lidar measurements show the V4 1064 nm calibration coefficients to within ~ 3 %.
Hongyu Guo, Athanasios Nenes, and Rodney J. Weber
Atmos. Chem. Phys., 18, 17307–17323,Short summary
Overprediction of fine-particle ammonium-sulfate molar ratios (R) by thermodynamic models is suggested as evidence for organic aerosol limiting the condensation of ammonia onto particles, with significant impacts on aerosol chemistry. We find that the effects of small amounts of salt and dust, combined with measurement artifacts, explain the discrepancy in R. These results are highly insensitive to mixing state. This means that aerosol predictions are much more robust than thought before.
Maryam Abdi-Oskouei, Gabriele Pfister, Frank Flocke, Negin Sobhani, Pablo Saide, Alan Fried, Dirk Richter, Petter Weibring, James Walega, and Gregory Carmichael
Atmos. Chem. Phys., 18, 16863–16883,Short summary
This study presents a quantification of model uncertainties due to configurations and errors in the emission inventories. The analysis includes performing simulations with different configurations and comparisons with airborne and ground-based observations with a focus on capturing transport and emissions from the oil and gas sector. The presented results reflect the challenges that one may face when attempting to improve emission inventories by contrasting measured with modeled concentrations.
Sylvia C. Sullivan, Christian Barthlott, Jonathan Crosier, Ilya Zhukov, Athanasios Nenes, and Corinna Hoose
Atmos. Chem. Phys., 18, 16461–16480,Short summary
Ice crystal formation in clouds can occur via thermodynamic nucleation, but also via mechanical collisions between pre-existing crystals or co-existing droplets. When descriptions of this mechanical ice generation are implemented into the COSMO weather model, we find that the contributions to crystal number from thermodynamic and mechanical processes are of the same order. Mechanical ice generation also intensifies differences in precipitation intensity between dynamic and quiescent regions.
Stelios Myriokefalitakis, Akinori Ito, Maria Kanakidou, Athanasios Nenes, Maarten C. Krol, Natalie M. Mahowald, Rachel A. Scanza, Douglas S. Hamilton, Matthew S. Johnson, Nicholas Meskhidze, Jasper F. Kok, Cecile Guieu, Alex R. Baker, Timothy D. Jickells, Manmohan M. Sarin, Srinivas Bikkina, Rachel Shelley, Andrew Bowie, Morgane M. G. Perron, and Robert A. Duce
Biogeosciences, 15, 6659–6684,Short summary
The first atmospheric iron (Fe) deposition model intercomparison is presented in this study, as a result of the deliberations of the United Nations Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP; http://www.gesamp.org/) Working Group 38. We conclude that model diversity over remote oceans reflects uncertainty in the Fe content parameterizations of dust aerosols, combustion aerosol emissions and the size distribution of transported aerosol Fe.
Elizabeth M. Lennartson, Jun Wang, Juping Gu, Lorena Castro Garcia, Cui Ge, Meng Gao, Myungje Choi, Pablo E. Saide, Gregory R. Carmichael, Jhoon Kim, and Scott J. Janz
Atmos. Chem. Phys., 18, 15125–15144,Short summary
This paper is among the first to study the diurnal variations of AOD, PM2.5, and their relationships in South Korea. We show that the PM2.5–AOD relationship has strong diurnal variations, and, hence, using AOD data retrieved from geostationary satellite can improve the monitoring of surface PM2.5 air quality on a daily basis as well as constrain the diurnal variation of aerosol emission.
Michael S. Diamond, Amie Dobracki, Steffen Freitag, Jennifer D. Small Griswold, Ashley Heikkila, Steven G. Howell, Mary E. Kacarab, James R. Podolske, Pablo E. Saide, and Robert Wood
Atmos. Chem. Phys., 18, 14623–14636,Short summary
Smoke from Africa can mix into clouds over the southeast Atlantic and create new droplets, which brightens the clouds, reflects more sunlight, and thus cools the region. Using aircraft data from a NASA field campaign, we find that cloud properties are correlated with smoke as expected when the smoke is below the clouds but not when smoke is above the clouds because it takes several days for clouds to mix smoke downward. We recommend methods that can track clouds as they move for future studies.
Sara Bacer, Sylvia C. Sullivan, Vlassis A. Karydis, Donifan Barahona, Martina Krämer, Athanasios Nenes, Holger Tost, Alexandra P. Tsimpidi, Jos Lelieveld, and Andrea Pozzer
Geosci. Model Dev., 11, 4021–4041,Short summary
The complexity of ice nucleation mechanisms and aerosol--ice interactions makes their representation still challenging in atmospheric models. We have implemented a comprehensive ice crystal formation parameterization in the global chemistry-climate model EMAC to improve the representation of ice crystal number concentrations. The newly implemented parameterization takes into account processes which were previously neglected by the standard version of the model.
Petros Vasilakos, Armistead Russell, Rodney Weber, and Athanasios Nenes
Atmos. Chem. Phys., 18, 12765–12775,Short summary
In this work, we investigated the role of emission reductions on aerosol acidity and particulate nitrate. We found that models exhibit positive biases in pH predictions, attributed to very high levels of crustal elements (Mg, Ca, K) in model simulations, which in turn led to an increasing aerosol pH trend over the past decade and allowed nitrate to become an important component of aerosol, which is inconsistent with the measurements, highlighting the importance of accurate pH prediction.
Hongyu Guo, Rene Otjes, Patrick Schlag, Astrid Kiendler-Scharr, Athanasios Nenes, and Rodney J. Weber
Atmos. Chem. Phys., 18, 12241–12256,Short summary
Reduction in ammonia has been proposed as a way to lower fine particle mass and improve air quality, but gas-phase ammonia is linked to agricultural productivity. We assess the feasibility of ammonia control at a variety of locations through an aerosol thermodynamic analysis. We show that aerosol response to ammonia control is highly nonlinear and only becomes effective when ambient particle pH drops below approximately 3. Particle pH is a relevant aerosol air quality parameter.
Theodora Nah, Hongyu Guo, Amy P. Sullivan, Yunle Chen, David J. Tanner, Athanasios Nenes, Armistead Russell, Nga Lee Ng, L. Gregory Huey, and Rodney J. Weber
Atmos. Chem. Phys., 18, 11471–11491,Short summary
We present measurements from a field study conducted in an agriculturally intensive region in the southeastern US during the fall of 2016 to investigate how NH3 affects particle acidity and SOA formation via gas–particle partitioning of semi-volatile organic acids. For this study, higher NH3 concentrations relative to what has been measured in the region in previous studies had minor effects on PM1 organic acids and their influence on the overall organic aerosol and PM1 mass concentrations.
Evangelia Kostenidou, Eleni Karnezi, James R. Hite Jr., Aikaterini Bougiatioti, Kate Cerully, Lu Xu, Nga L. Ng, Athanasios Nenes, and Spyros N. Pandis
Atmos. Chem. Phys., 18, 5799–5819,Short summary
The volatility distribution of organic aerosol (OA) and its sources during the Southern Oxidant and Aerosol Study (SOAS) was estimated. The volatility distribution of all components covered a wide range including both semi-volatile and low-volatility components. The oxygen content of the factors can be combined with their estimated volatility and hygroscopicity to provide a better view of their physical properties.
Julia Schmale, Silvia Henning, Stefano Decesari, Bas Henzing, Helmi Keskinen, Karine Sellegri, Jurgita Ovadnevaite, Mira L. Pöhlker, Joel Brito, Aikaterini Bougiatioti, Adam Kristensson, Nikos Kalivitis, Iasonas Stavroulas, Samara Carbone, Anne Jefferson, Minsu Park, Patrick Schlag, Yoko Iwamoto, Pasi Aalto, Mikko Äijälä, Nicolas Bukowiecki, Mikael Ehn, Göran Frank, Roman Fröhlich, Arnoud Frumau, Erik Herrmann, Hartmut Herrmann, Rupert Holzinger, Gerard Kos, Markku Kulmala, Nikolaos Mihalopoulos, Athanasios Nenes, Colin O'Dowd, Tuukka Petäjä, David Picard, Christopher Pöhlker, Ulrich Pöschl, Laurent Poulain, André Stephan Henry Prévôt, Erik Swietlicki, Meinrat O. Andreae, Paulo Artaxo, Alfred Wiedensohler, John Ogren, Atsushi Matsuki, Seong Soo Yum, Frank Stratmann, Urs Baltensperger, and Martin Gysel
Atmos. Chem. Phys., 18, 2853–2881,Short summary
Collocated long-term observations of cloud condensation nuclei (CCN) number concentrations, particle number size distributions and chemical composition from 12 sites are synthesized. Observations cover coastal environments, the Arctic, the Mediterranean, the boreal and rain forest, high alpine and continental background sites, and Monsoon-influenced areas. We interpret regional and seasonal variability. CCN concentrations are predicted with the κ–Köhler model and compared to the measurements.
Sylvia C. Sullivan, Corinna Hoose, Alexei Kiselev, Thomas Leisner, and Athanasios Nenes
Atmos. Chem. Phys., 18, 1593–1610,Short summary
Ice multiplication (IM) processes can have a profound impact on cloud and precipitation development but are poorly understood. Here we study whether a lower limit of ice nuclei exists to initiate IM. The lower limit is found to be extremely low (0.01 per liter or less). A counterintuitive but profound conclusion thus emerges: IM requires cloud formation around a thermodynamic
sweet spotand is sensitive to fluctuations in cloud condensation nuclei concentration alone.
Brent N. Holben, Jhoon Kim, Itaru Sano, Sonoyo Mukai, Thomas F. Eck, David M. Giles, Joel S. Schafer, Aliaksandr Sinyuk, Ilya Slutsker, Alexander Smirnov, Mikhail Sorokin, Bruce E. Anderson, Huizheng Che, Myungje Choi, James H. Crawford, Richard A. Ferrare, Michael J. Garay, Ukkyo Jeong, Mijin Kim, Woogyung Kim, Nichola Knox, Zhengqiang Li, Hwee S. Lim, Yang Liu, Hal Maring, Makiko Nakata, Kenneth E. Pickering, Stuart Piketh, Jens Redemann, Jeffrey S. Reid, Santo Salinas, Sora Seo, Fuyi Tan, Sachchida N. Tripathi, Owen B. Toon, and Qingyang Xiao
Atmos. Chem. Phys., 18, 655–671,Short summary
Aerosol particles, such as smoke, vary over space and time. This paper describes a series of very high-resolution ground-based aerosol measurement networks and associated studies that contributed new understanding of aerosol processes and detailed comparisons to satellite aerosol validation. Significantly, these networks also provide an opportunity to statistically relate grab samples of an aerosol parameter to companion satellite observations, a step toward air quality assessment from space.
Antonio Di Noia, Otto P. Hasekamp, Lianghai Wu, Bastiaan van Diedenhoven, Brian Cairns, and John E. Yorks
Atmos. Meas. Tech., 10, 4235–4252,Short summary
In this paper an algorithm for the retrieval of aerosol properties from NASA Research Scanning Polarimeter (RSP) data is presented. An artificial neural network is used to produce a first estimate of the aerosol properties, which is then improved using an iterative retrieval scheme based on Phillips–Tikhonov regularization. Using the neural network retrievals as a first guess for the Phillips–Tikhonov improved the retrieval convergence, confirming results previously found on ground-based data.
Moritz Haarig, Albert Ansmann, Dietrich Althausen, André Klepel, Silke Groß, Volker Freudenthaler, Carlos Toledano, Rodanthi-Elisavet Mamouri, David A. Farrell, Damien A. Prescod, Eleni Marinou, Sharon P. Burton, Josef Gasteiger, Ronny Engelmann, and Holger Baars
Atmos. Chem. Phys., 17, 10767–10794,Short summary
Our measurements performed with a lidar on Barbados give a vertical profile of Saharan dust, which was transported over 5000 km across the Atlantic. The new triple-wavelength depolarization technique reveals more information about the shape and size of dust, which will improve our understanding of the aging process of dust in the atmosphere and its representation in dust models. Changing properties of dust particles influence the solar radiation and the cloud properties and thus our climate.
Kenneth Sinclair, Bastiaan van Diedenhoven, Brian Cairns, John Yorks, Andrzej Wasilewski, and Matthew McGill
Atmos. Meas. Tech., 10, 2361–2375,Short summary
We present a multi-angular contrast approach to retrieve cloud top height (CTH) using photogrammetry. We demonstrate the method’s ability to retrieve heights of multiple cloud layers within single footprints, using the multiple views available for each footprint. This paper provides an in-depth description and performance analysis of the CTH retrieval technique and the retrieved cloud heights are evaluated using collocated data from the Cloud Physics Lidar.
Khairunnisa Yahya, Timothy Glotfelty, Kai Wang, Yang Zhang, and Athanasios Nenes
Geosci. Model Dev., 10, 2333–2363,
Patricia Sawamura, Richard H. Moore, Sharon P. Burton, Eduard Chemyakin, Detlef Müller, Alexei Kolgotin, Richard A. Ferrare, Chris A. Hostetler, Luke D. Ziemba, Andreas J. Beyersdorf, and Bruce E. Anderson
Atmos. Chem. Phys., 17, 7229–7243,Short summary
We present a detailed evaluation of physical properties of aerosols, like aerosol number concentration and aerosol size, obtained from an advanced, airborne, multi-wavelength high-spectral-resolution lidar (HSRL-2) system. These lidar-retrieved physical properties were compared to airborne in situ measurements. Our findings highlight the advantages of advanced HSRL measurements and retrievals to help constrain the vertical distribution of aerosol volume or mass loading relevant for air quality.
Petros Vasilakos, Yong-Ηa Kim, Jeffrey R. Pierce, Sotira Yiacoumi, Costas Tsouris, and Athanasios Nenes
Geosci. Model Dev. Discuss.,
Revised manuscript not acceptedShort summary
Radioactive charging can significantly impact the way radioactive aerosols behave, and as a result their lifetime, but such effects are neglected in predictive model studies of radioactive plumes. We extend a well-established model that simulates the evolution of atmospheric particulate matter to account for radioactive charging effects in an accurate and computationally efficient way. It is shown that radioactivity can strongly impact the deposition patterns of aerosol.
Hongyu Guo, Jiumeng Liu, Karl D. Froyd, James M. Roberts, Patrick R. Veres, Patrick L. Hayes, Jose L. Jimenez, Athanasios Nenes, and Rodney J. Weber
Atmos. Chem. Phys., 17, 5703–5719,Short summary
Fine particle pH is linked to many environmental impacts by affecting particle concentration and composition. Predicted Pasadena, CA (CalNex campaign), PM1 pH is 1.9 and PM2.5 pH 2.7, the latter higher due to sea salts. The model predicted gas–particle partitionings of HNO3–NO3−, NH3–NH4+, and HCl–Cl− are in good agreement, verifying the model predictions. A summary of contrasting locations in the US and eastern Mediterranean shows fine particles are generally highly acidic, with pH below 3.
Vlassis A. Karydis, Alexandra P. Tsimpidi, Sara Bacer, Andrea Pozzer, Athanasios Nenes, and Jos Lelieveld
Atmos. Chem. Phys., 17, 5601–5621,Short summary
The importance of mineral dust for cloud droplet formation is studied by considering the adsorption activation of insoluble dust particles and the thermodynamic interactions between mineral cations and inorganic anions. This study demonstrates that a comprehensive treatment of the CCN activity of mineral dust and its chemical and thermodynamic interactions with inorganic species by chemistry climate models is important to realistically account for aerosol–chemistry–cloud–climate interaction.
Samuel Rémy, Andreas Veira, Ronan Paugam, Mikhail Sofiev, Johannes W. Kaiser, Franco Marenco, Sharon P. Burton, Angela Benedetti, Richard J. Engelen, Richard Ferrare, and Jonathan W. Hair
Atmos. Chem. Phys., 17, 2921–2942,Short summary
Biomass burning emission injection heights are an important source of uncertainty in global climate and atmospheric composition modelling. This work provides a global daily data set of injection heights computed by two very different algorithms, which coherently complete a global biomass burning emissions database. The two data sets were compared and validated against observations, and their use was found to improve forecasts of carbonaceous aerosols in two case studies.
Alexandra Tsekeri, Vassilis Amiridis, Franco Marenco, Athanasios Nenes, Eleni Marinou, Stavros Solomos, Phil Rosenberg, Jamie Trembath, Graeme J. Nott, James Allan, Michael Le Breton, Asan Bacak, Hugh Coe, Carl Percival, and Nikolaos Mihalopoulos
Atmos. Meas. Tech., 10, 83–107,Short summary
The In situ/Remote sensing aerosol Retrieval Algorithm (IRRA) provides vertical profiles of aerosol optical, microphysical and hygroscopic properties from airborne in situ and remote sensing measurements. The algorithm is highly advantageous for aerosol characterization in humid conditions, employing the ISORROPIA II model for acquiring the particle hygroscopic growth. IRRA can find valuable applications in aerosol–cloud interaction schemes and in validation of active space-borne sensors.
Havala O. T. Pye, Benjamin N. Murphy, Lu Xu, Nga L. Ng, Annmarie G. Carlton, Hongyu Guo, Rodney Weber, Petros Vasilakos, K. Wyat Appel, Sri Hapsari Budisulistiorini, Jason D. Surratt, Athanasios Nenes, Weiwei Hu, Jose L. Jimenez, Gabriel Isaacman-VanWertz, Pawel K. Misztal, and Allen H. Goldstein
Atmos. Chem. Phys., 17, 343–369,Short summary
We use a chemical transport model to examine how organic compounds in the atmosphere interact with water present in particles. Organic compounds themselves lead to water uptake, and organic compounds interact with water associated with inorganic compounds in the rural southeast atmosphere. Including interactions of organic compounds with water requires a treatment of nonideality to more accurately represent aerosol observations during the Southern Oxidant and Aerosol Study (SOAS) 2013.
Panayiotis Kalkavouras, Elissavet Bossioli, Spiros Bezantakos, Aikaterini Bougiatioti, Nikos Kalivitis, Iasonas Stavroulas, Giorgos Kouvarakis, Anna P. Protonotariou, Aggeliki Dandou, George Biskos, Nikolaos Mihalopoulos, Athanasios Nenes, and Maria Tombrou
Atmos. Chem. Phys., 17, 175–192,Short summary
Concentrations of chemically and size-resolved submicron aerosol particles along with concentrations of gases and meteorological variables were measured at Santorini and Finokalia (central and southern Aegean Sea) during the Etesians. Particle nucleation bursts were recorded. The NPF can double CCN number (at 0.1 % supersaturation), but the resulting strong competition for water vapor in cloudy updrafts decreases maximum supersaturation by 14 % and augments the potential droplet number by 12 %.
Stelios Myriokefalitakis, Athanasios Nenes, Alex R. Baker, Nikolaos Mihalopoulos, and Maria Kanakidou
Biogeosciences, 13, 6519–6543,Short summary
The global atmospheric cycle of P is simulated accounting for natural and anthropogenic sources, acid dissolution of dust aerosol and changes in atmospheric acidity. Simulations show that P-containing dust dissolution flux may have increased in the last 150 years but is expected to decrease in the future, and biological particles are important carriers of bioavailable P to the ocean. These insights to the P cycle have important implications for marine ecosystem responses to climate change.
Sharon P. Burton, Eduard Chemyakin, Xu Liu, Kirk Knobelspiesse, Snorre Stamnes, Patricia Sawamura, Richard H. Moore, Chris A. Hostetler, and Richard A. Ferrare
Atmos. Meas. Tech., 9, 5555–5574,Short summary
Retrievals of aerosol microphysics exist for ground-based, airborne, and future space-borne lidar measurements. We investigate the information content of a lidar measurement system, using only a forward model but no explicit inversion. The simplified aerosol used here is applicable as a best case for all retrievals in the absence of additional constraints. We report (1) information content of the measurements; (2) uncertainties on the retrieved parameters; and (3) sources of compensating errors.
Lei Zhu, Daniel J. Jacob, Patrick S. Kim, Jenny A. Fisher, Karen Yu, Katherine R. Travis, Loretta J. Mickley, Robert M. Yantosca, Melissa P. Sulprizio, Isabelle De Smedt, Gonzalo González Abad, Kelly Chance, Can Li, Richard Ferrare, Alan Fried, Johnathan W. Hair, Thomas F. Hanisco, Dirk Richter, Amy Jo Scarino, James Walega, Petter Weibring, and Glenn M. Wolfe
Atmos. Chem. Phys., 16, 13477–13490,Short summary
HCHO column data are widely used as a proxy for VOCs emissions, but validation of the data has been extremely limited. We use accurate aircraft observations to validate and intercompare 6 HCHO retrievals with GEOS-Chem as the intercomparison platform. Retrievals are interconsistent in spatial variability over the SE US and in daily variability, but are biased low by 20–51 %. Our work supports the use of HCHO column as a quantitative proxy for isoprene emission after correction of the low bias.
Hiren Jethva, Omar Torres, Lorraine Remer, Jens Redemann, John Livingston, Stephen Dunagan, Yohei Shinozuka, Meloe Kacenelenbogen, Michal Segal Rosenheimer, and Rob Spurr
Atmos. Meas. Tech., 9, 5053–5062,Short summary
Validation of the above-cloud aerosol optical depth retrieved using the "color ratio" method applied to MODIS cloudy-sky measurements against airborne direct measurements made by NASA’s AATS and 4STAR sun photometers during SAFARI-2000, ACE-ASIA 2001, and SEAC4RS 2013 reveals a good level of agreement (difference < 0.1), in which most matchups are found be constrained within the estimated uncertainties associated with the MODIS retrievals (-10 % to +50 %).
Meng Gao, Gregory R. Carmichael, Pablo E. Saide, Zifeng Lu, Man Yu, David G. Streets, and Zifa Wang
Atmos. Chem. Phys., 16, 11837–11851,Short summary
The WRF-Chem model was used to examine how the winter PM2.5 concentrations change in response to changes in emissions and meteorology in North China from 1960 to 2010. The discussions in this study indicate that dramatic changes in emissions are the main cause of increasing haze events in North China, and long-term trends in atmospheric circulations maybe another important cause. We also found aerosol feedbacks have been significantly enhanced from 1960 to 2010, due to higher aerosol loadings.
Ivan Ortega, Sean Coburn, Larry K. Berg, Kathy Lantz, Joseph Michalsky, Richard A. Ferrare, Johnathan W. Hair, Chris A. Hostetler, and Rainer Volkamer
Atmos. Meas. Tech., 9, 3893–3910,Short summary
We present an inherently calibrated retrieval to measure aerosol optical depth (AOD) and the aerosol phase function parameter, g, based on measurements of azimuth distributions of the Raman scattering probability (RSP), the near-absolute rotational Raman scattering (RRS) intensity by the University of Colorado two-dimensional (2-D) MAX-DOAS. The retrievals are maximally sensitive at low AOD and do not require absolute radiance calibration. We compare results with data from independent sensors.
Carsten Warneke, Michael Trainer, Joost A. de Gouw, David D. Parrish, David W. Fahey, A. R. Ravishankara, Ann M. Middlebrook, Charles A. Brock, James M. Roberts, Steven S. Brown, Jonathan A. Neuman, Brian M. Lerner, Daniel Lack, Daniel Law, Gerhard Hübler, Iliana Pollack, Steven Sjostedt, Thomas B. Ryerson, Jessica B. Gilman, Jin Liao, John Holloway, Jeff Peischl, John B. Nowak, Kenneth C. Aikin, Kyung-Eun Min, Rebecca A. Washenfelder, Martin G. Graus, Mathew Richardson, Milos Z. Markovic, Nick L. Wagner, André Welti, Patrick R. Veres, Peter Edwards, Joshua P. Schwarz, Timothy Gordon, William P. Dube, Stuart A. McKeen, Jerome Brioude, Ravan Ahmadov, Aikaterini Bougiatioti, Jack J. Lin, Athanasios Nenes, Glenn M. Wolfe, Thomas F. Hanisco, Ben H. Lee, Felipe D. Lopez-Hilfiker, Joel A. Thornton, Frank N. Keutsch, Jennifer Kaiser, Jingqiu Mao, and Courtney D. Hatch
Atmos. Meas. Tech., 9, 3063–3093,Short summary
In this paper we describe the experimental approach, the science goals and early results of the NOAA SENEX campaign, which was focused on studying the interactions between biogenic and anthropogenic emissions to form secondary pollutants. During SENEX, the NOAA WP-3D aircraft conducted 20 research flights between 27 May and 10 July 2013 based out of Smyrna, TN. The SENEX flights included day- and nighttime flights in the Southeast as well as flights over areas with intense shale gas extraction.
Feng Xu, Oleg Dubovik, Peng-Wang Zhai, David J. Diner, Olga V. Kalashnikova, Felix C. Seidel, Pavel Litvinov, Andrii Bovchaliuk, Michael J. Garay, Gerard van Harten, and Anthony B. Davis
Atmos. Meas. Tech., 9, 2877–2907,Short summary
We developed an algorithm for aerosol and water-leaving radiance retrieval in a simultaneous way.
Aikaterini Bougiatioti, Spiros Bezantakos, Iasonas Stavroulas, Nikos Kalivitis, Panagiotis Kokkalis, George Biskos, Nikolaos Mihalopoulos, Alexandros Papayannis, and Athanasios Nenes
Atmos. Chem. Phys., 16, 7389–7409,Short summary
BBOA from long-range transport exhibits increased CCN concentrations for particles larger than 100 nm. At the same time the hygroscopicity parameter decreased for all particle sizes, as sub-100 nm particles appear to be richer in less hygroscopic organic material, while larger particles become less hygroscopic due to condensation of less hygroscopic gaseous compounds. Finally, atmospheric processing of freshly emitted BBOA to more oxidized organic aerosol can result in a 2-fold increase of κ.
Swen Metzger, Benedikt Steil, Mohamed Abdelkader, Klaus Klingmüller, Li Xu, Joyce E. Penner, Christos Fountoukis, Athanasios Nenes, and Jos Lelieveld
Atmos. Chem. Phys., 16, 7213–7237,Short summary
We introduce an unique single parameter framework to efficiently parameterize the aerosol water uptake for mixtures of semi-volatile and non-volatile compounds, being entirely based on the single solute specific coefficient introduced in Metzger et al. (2012).
Patricia Sawamura, Richard H. Moore, Sharon P. Burton, Eduard Chemyakin, Detlef Müller, Alexei Kolgotin, Richard A. Ferrare, Chris A. Hostetler, Luke D. Ziemba, Andreas J. Beyersdorf, and Bruce E. Anderson
Atmos. Chem. Phys. Discuss.,
Revised manuscript not accepted
Aikaterini Bougiatioti, Panayiota Nikolaou, Iasonas Stavroulas, Giorgos Kouvarakis, Rodney Weber, Athanasios Nenes, Maria Kanakidou, and Nikolaos Mihalopoulos
Atmos. Chem. Phys., 16, 4579–4591,Short summary
Atmospheric aerosols and relevant parameters were measured in the eastern Mediterranean during summer and fall 2012. Submicron aerosol water can contribute up to 33 % of total mass, and 27.5 % of this can be associated with organics. Using these data, the pH of the submicron aerosols was calculated to be highly acidic, varying from 0.5 to 2.8 and independently of air masses origin. Such pH values could increase nutrient availability and thus sea water productivity of the Mediterranean Sea.
Christopher R. Hoyle, Clare S. Webster, Harald E. Rieder, Athanasios Nenes, Emanuel Hammer, Erik Herrmann, Martin Gysel, Nicolas Bukowiecki, Ernest Weingartner, Martin Steinbacher, and Urs Baltensperger
Atmos. Chem. Phys., 16, 4043–4061,Short summary
A simple statistical model to predict the number of aerosols which activate to form cloud droplets in warm clouds has been established, based on regression analysis of data from the high-altitude site Jungfraujoch. It is found that cloud droplet formation at the Jungfraujoch is predominantly controlled by the number concentration of aerosol particles. A statistical model based on only the number of particles larger than 80nm can explain 79 % of the observed variance in droplet numbers.
Yong-ha Kim, Sotira Yiacoumi, Athanasios Nenes, and Costas Tsouris
Atmos. Chem. Phys., 16, 3449–3462,Short summary
Three microphysical approaches are proposed to incorporate mutual effects of particle charging and coagulation in predictions of transient charge and size distributions of atmospheric particles, including radioactive aerosols. The three approaches have different levels of complexities and are applicable to various laboratory and field atmospheric studies. Also, these approaches can be easily incorporated into aerosol transport models at different scales to account for particle charging effects.
Joel McCorkel, Brian Cairns, and Andrzej Wasilewski
Atmos. Meas. Tech., 9, 955–962,Short summary
The transfer and maintenance of international radiometric standards to satellite remote-sensing instruments is a labor-intensive and costly one. The goal is to provide specific examples for calibration implementation for a potential instrument mission and, with this, advance debate on the roles that the various satellite calibration techniques play in providing the best radiometric standards for Earth-observing sensors.
Sylvia C. Sullivan, Ricardo Morales Betancourt, Donifan Barahona, and Athanasios Nenes
Atmos. Chem. Phys., 16, 2611–2629,Short summary
We use the adjoint model of a cirrus parameterization to quantify sources of crystal variability for various ice-nucleating spectra and output from CAM5. The sensitivities can be directly linked to nucleation regime and efficiency of various INP. The lab-based spectrum calculates much higher INP efficiencies than field-based ones, owing to aerosol surface properties. The sensitivity to temperature tends to be low, due to the compensating effects of temperature on INP spectrum parameters.
M. Gao, G. R. Carmichael, Y. Wang, P. E. Saide, M. Yu, J. Xin, Z. Liu, and Z. Wang
Atmos. Chem. Phys., 16, 1673–1691,Short summary
The WRF-Chem model was applied to study the 2010 winter haze in North China. Air pollutants outside Beijing contributed about 64.5 % to the PM2.5 levels in Beijing during this haze event, and most of them are from south Hebei, Tianjin city, Shandong and Henan provinces. In addition, aerosol feedback has important impacts on surface temperature, Relative Humidity (RH) and wind speeds, and these meteorological variables affect aerosol distribution and formation in turn.
L. M. Zamora, R. A. Kahn, M. J. Cubison, G. S. Diskin, J. L. Jimenez, Y. Kondo, G. M. McFarquhar, A. Nenes, K. L. Thornhill, A. Wisthaler, A. Zelenyuk, and L. D. Ziemba
Atmos. Chem. Phys., 16, 715–738,Short summary
Based on extensive aircraft campaigns, we quantify how biomass burning smoke affects subarctic and Arctic liquid cloud microphysical properties. Enhanced cloud albedo may decrease short-wave radiative flux by between 2 and 4 Wm2 or more in some subarctic conditions. Smoke halved average cloud droplet diameter. In one case study, it also appeared to limit droplet formation. Numerous Arctic background Aitken particles can also interact with combustion particles, perhaps affecting their properties.
S. P. Burton, J. W. Hair, M. Kahnert, R. A. Ferrare, C. A. Hostetler, A. L. Cook, D. B. Harper, T. A. Berkoff, S. T. Seaman, J. E. Collins, M. A. Fenn, and R. R. Rogers
Atmos. Chem. Phys., 15, 13453–13473,Short summary
The manuscript describes measurements of particle depolarization ratio from the NASA airborne HSRL-2 at three wavelengths, for two dust cases and a smoke case. Differences in the spectral dependence of particle depolarization ratio are due to the sizes of the non-spherical particles, large for dust and small for smoke. The large depolarization at 355nm for smoke has not been previously reported and may impact aerosol typing when only a single wavelength is available.
M. Paramonov, V.-M. Kerminen, M. Gysel, P. P. Aalto, M. O. Andreae, E. Asmi, U. Baltensperger, A. Bougiatioti, D. Brus, G. P. Frank, N. Good, S. S. Gunthe, L. Hao, M. Irwin, A. Jaatinen, Z. Jurányi, S. M. King, A. Kortelainen, A. Kristensson, H. Lihavainen, M. Kulmala, U. Lohmann, S. T. Martin, G. McFiggans, N. Mihalopoulos, A. Nenes, C. D. O'Dowd, J. Ovadnevaite, T. Petäjä, U. Pöschl, G. C. Roberts, D. Rose, B. Svenningsson, E. Swietlicki, E. Weingartner, J. Whitehead, A. Wiedensohler, C. Wittbom, and B. Sierau
Atmos. Chem. Phys., 15, 12211–12229,Short summary
The research paper presents the first comprehensive overview of field measurements with the CCN Counter performed at a large number of locations around the world within the EUCAARI framework. The paper sheds light on the CCN number concentrations and activated fractions around the world and their dependence on the water vapour supersaturation ratio, the dependence of aerosol hygroscopicity on particle size, and seasonal and diurnal variation of CCN activation and hygroscopic properties.
M. Ottaviani, B. van Diedenhoven, and B. Cairns
The Cryosphere, 9, 1933–1942,
N. Kalivitis, V.-M. Kerminen, G. Kouvarakis, I. Stavroulas, A. Bougiatioti, A. Nenes, H. E. Manninen, T. Petäjä, M. Kulmala, and N. Mihalopoulos
Atmos. Chem. Phys., 15, 9203–9215,Short summary
Cloud condensation nuclei (CCN) production associated with atmospheric new particle formation (NPF) is presented, and this is the first direct evidence of CCN production resulting from NPF in the eastern Mediterranean atmosphere. We show that condensation of both gaseous sulfuric acid and organic compounds from multiple sources leads to the rapid growth of nucleated particles. Sub-100nm particles were found to be substantially less hygroscopic than larger particles during the active NPF period.
S. H. Budisulistiorini, X. Li, S. T. Bairai, J. Renfro, Y. Liu, Y. J. Liu, K. A. McKinney, S. T. Martin, V. F. McNeill, H. O. T. Pye, A. Nenes, M. E. Neff, E. A. Stone, S. Mueller, C. Knote, S. L. Shaw, Z. Zhang, A. Gold, and J. D. Surratt
Atmos. Chem. Phys., 15, 8871–8888,Short summary
Isoprene epoxydiols (IEPOX) are major gas-phase products from the atmospheric oxidation of isoprene that yield secondary organic aerosol (SOA) by reactive uptake onto acidic sulfate aerosol. We report a substantial contribution of IEPOX-derived SOA to the total fine aerosol collected during summer. IEPOX-derived SOA measured by online and offline mass spectrometry techniques is correlated with acidic sulfate aerosol, demonstrating the critical role of anthropogenic emissions in its formation.
K. M. Cerully, A. Bougiatioti, J. R. Hite Jr., H. Guo, L. Xu, N. L. Ng, R. Weber, and A. Nenes
Atmos. Chem. Phys., 15, 8679–8694,Short summary
The hygroscopicity of SE US aerosol is mostly water-soluble, with a hygroscopicity that is insensitive to partial volatilization in a thermodenuder. The most and least oxidized components of the aerosol are the most hygroscopic of organic constituents. No clear relationship was found between organic aerosol hygroscopicity and oxygen-to-carbon ratio. The aerosol factors covary in a way that induces the observed diurnal invariance in total organic hygroscopicity.
L. Hildebrandt Ruiz, A. L. Paciga, K. M. Cerully, A. Nenes, N. M. Donahue, and S. N. Pandis
Atmos. Chem. Phys., 15, 8301–8313,Short summary
Secondary organic aerosol (SOA) is transformed after its initial formation. We explored the effects of this chemical aging on the composition, mass yield, volatility, and hygroscopicity of SOA formed from the photo-oxidation of small aromatic volatile organic compounds. Higher exposure to the hydroxyl radical resulted in different SOA composition, average carbon oxidation state, and mass yield. The vapor pressure of SOA formed under different conditions varied by as much as a factor of 30.
Y. Shinozuka, A. D. Clarke, A. Nenes, A. Jefferson, R. Wood, C. S. McNaughton, J. Ström, P. Tunved, J. Redemann, K. L. Thornhill, R. H. Moore, T. L. Lathem, J. J. Lin, and Y. J. Yoon
Atmos. Chem. Phys., 15, 7585–7604,
S. Myriokefalitakis, N. Daskalakis, N. Mihalopoulos, A. R. Baker, A. Nenes, and M. Kanakidou
Biogeosciences, 12, 3973–3992,Short summary
The global atmospheric cycle of Fe is simulated accounting for natural and combustion sources, proton- and organic ligand-promoted Fe dissolution from dust aerosol and changes in anthropogenic emissions, and thus in atmospheric acidity. Simulations show that Fe dissolution may have increased in the last 150 years and is expected to decrease due to air pollution regulations. Reductions in dissolved-Fe deposition can further limit the primary productivity over high-nutrient-low-chlorophyll water.
L. Wu, O. Hasekamp, B. van Diedenhoven, and B. Cairns
Atmos. Meas. Tech., 8, 2625–2638,
M. Bocquet, H. Elbern, H. Eskes, M. Hirtl, R. Žabkar, G. R. Carmichael, J. Flemming, A. Inness, M. Pagowski, J. L. Pérez Camaño, P. E. Saide, R. San Jose, M. Sofiev, J. Vira, A. Baklanov, C. Carnevale, G. Grell, and C. Seigneur
Atmos. Chem. Phys., 15, 5325–5358,Short summary
Data assimilation is used in atmospheric chemistry models to improve air quality forecasts, construct re-analyses of concentrations, and perform inverse modeling. Coupled chemistry meteorology models (CCMM) are atmospheric chemistry models that simulate meteorological processes and chemical transformations jointly. We review here the current status of data assimilation in atmospheric chemistry models, with a particular focus on future prospects for data assimilation in CCMM.
H. Guo, L. Xu, A. Bougiatioti, K. M. Cerully, S. L. Capps, J. R. Hite Jr., A. G. Carlton, S.-H. Lee, M. H. Bergin, N. L. Ng, A. Nenes, and R. J. Weber
Atmos. Chem. Phys., 15, 5211–5228,Short summary
Particle pH can affect many aerosol processes, including gas-particle partitioning, SOA formation, and mobilization of toxic redox metals. pH is challenging to directly measure and often improperly characterized by proxies like ion balances or molar ratios of measured aerosol ionic species. We present a detailed analysis predicting pH with a thermodynamic model, verify the prediction, and test pH sensitivity to model inputs based on data from the SOAS field campaign.
C. J. Hennigan, J. Izumi, A. P. Sullivan, R. J. Weber, and A. Nenes
Atmos. Chem. Phys., 15, 2775–2790,Short summary
We show that the ion balance and molar ratio methods are unsuitable for use as aerosol pH proxies. Our recommendation is that 1) thermodynamic equilibrium models constrained by both gas and aerosol inputs run in the forward (open) mode, and 2) the phase partitioning of ammonia provides the best predictions of aerosol pH. Given the significance of acidity for numerous chemical processes in the atmosphere, the implications of this study are important and far reaching.
S. Kulkarni, N. Sobhani, J. P. Miller-Schulze, M. M. Shafer, J. J. Schauer, P. A. Solomon, P. E. Saide, S. N. Spak, Y. F. Cheng, H. A. C. Denier van der Gon, Z. Lu, D. G. Streets, G. Janssens-Maenhout, C. Wiedinmyer, J. Lantz, M. Artamonova, B. Chen, S. Imashev, L. Sverdlik, J. T. Deminter, B. Adhikary, A. D'Allura, C. Wei, and G. R. Carmichael
Atmos. Chem. Phys., 15, 1683–1705,Short summary
This study presents a regional-scale modeling analysis of aerosols in the Central Asia region including detailed characterization of seasonal source region and sector contributions along with the predicted changes in distribution of aerosols using 2030 future emission scenarios. The influence of long transport and impact of varied emission sources including dust, biomass burning, and anthropogenic sources on the regional aerosol distributions and the associated transport pathways are discussed.
M. C. Wyant, C. S. Bretherton, R. Wood, G. R. Carmichael, A. Clarke, J. Fast, R. George, W. I. Gustafson Jr., C. Hannay, A. Lauer, Y. Lin, J.-J. Morcrette, J. Mulcahy, P. E. Saide, S. N. Spak, and Q. Yang
Atmos. Chem. Phys., 15, 153–172,Short summary
Simulations from a group of GCMs, forecast models, and regional models are compared with aircraft and ship observations of the marine boundary layer (MBL) in the southeast Pacific region during the VOCALS-REx field campaign of October-November 2008. Gradients of cloud, aerosol, and chemical properties in and above the MBL extending from the Peruvian coast westward along 20 degrees south are compared during the period.
R. R. Rogers, M. A. Vaughan, C. A. Hostetler, S. P. Burton, R. A. Ferrare, S. A. Young, J. W. Hair, M. D. Obland, D. B. Harper, A. L. Cook, and D. M. Winker
Atmos. Meas. Tech., 7, 4317–4340,
S. Nordmann, Y. F. Cheng, G. R. Carmichael, M. Yu, H. A. C. Denier van der Gon, Q. Zhang, P. E. Saide, U. Pöschl, H. Su, W. Birmili, and A. Wiedensohler
Atmos. Chem. Phys., 14, 12683–12699,
Y. You, V. P. Kanawade, J. A. de Gouw, A. B. Guenther, S. Madronich, M. R. Sierra-Hernández, M. Lawler, J. N. Smith, S. Takahama, G. Ruggeri, A. Koss, K. Olson, K. Baumann, R. J. Weber, A. Nenes, H. Guo, E. S. Edgerton, L. Porcelli, W. H. Brune, A. H. Goldstein, and S.-H. Lee
Atmos. Chem. Phys., 14, 12181–12194,Short summary
Amiens play important roles in atmospheric secondary aerosol formation and human health, but the fast response measurements of amines are lacking. Here we show measurements in a southeastern US forest and a moderately polluted midwestern site. Our results show that gas to particle conversion is an important process that controls ambient amine concentrations and that biomass burning is an important source of amines.
T. F. Eck, B. N. Holben, J. S. Reid, A. Arola, R. A. Ferrare, C. A. Hostetler, S. N. Crumeyrolle, T. A. Berkoff, E. J. Welton, S. Lolli, A. Lyapustin, Y. Wang, J. S. Schafer, D. M. Giles, B. E. Anderson, K. L. Thornhill, P. Minnis, K. E. Pickering, C. P. Loughner, A. Smirnov, and A. Sinyuk
Atmos. Chem. Phys., 14, 11633–11656,
R. Morales Betancourt and A. Nenes
Geosci. Model Dev., 7, 2345–2357,
D. Müller, C. A. Hostetler, R. A. Ferrare, S. P. Burton, E. Chemyakin, A. Kolgotin, J. W. Hair, A. L. Cook, D. B. Harper, R. R. Rogers, R. W. Hare, C. S. Cleckner, M. D. Obland, J. Tomlinson, L. K. Berg, and B. Schmid
Atmos. Meas. Tech., 7, 3487–3496,
P. Sawamura, D. Müller, R. M. Hoff, C. A. Hostetler, R. A. Ferrare, J. W. Hair, R. R. Rogers, B. E. Anderson, L. D. Ziemba, A. J. Beyersdorf, K. L. Thornhill, E. L. Winstead, and B. N. Holben
Atmos. Meas. Tech., 7, 3095–3112,
J. D. Fast, J. Allan, R. Bahreini, J. Craven, L. Emmons, R. Ferrare, P. L. Hayes, A. Hodzic, J. Holloway, C. Hostetler, J. L. Jimenez, H. Jonsson, S. Liu, Y. Liu, A. Metcalf, A. Middlebrook, J. Nowak, M. Pekour, A. Perring, L. Russell, A. Sedlacek, J. Seinfeld, A. Setyan, J. Shilling, M. Shrivastava, S. Springston, C. Song, R. Subramanian, J. W. Taylor, V. Vinoj, Q. Yang, R. A. Zaveri, and Q. Zhang
Atmos. Chem. Phys., 14, 10013–10060,
D. Barahona, A. Molod, J. Bacmeister, A. Nenes, A. Gettelman, H. Morrison, V. Phillips, and A. Eichmann
Geosci. Model Dev., 7, 1733–1766,
B. Gantt, J. He, X. Zhang, Y. Zhang, and A. Nenes
Atmos. Chem. Phys., 14, 7485–7497,
A. J. Scarino, M. D. Obland, J. D. Fast, S. P. Burton, R. A. Ferrare, C. A. Hostetler, L. K. Berg, B. Lefer, C. Haman, J. W. Hair, R. R. Rogers, C. Butler, A. L. Cook, and D. B. Harper
Atmos. Chem. Phys., 14, 5547–5560,
G. Drozd, J. Woo, S. A. K. Häkkinen, A. Nenes, and V. F. McNeill
Atmos. Chem. Phys., 14, 5205–5215,
S. G. Howell, A. D. Clarke, S. Freitag, C. S. McNaughton, V. Kapustin, V. Brekovskikh, J.-L. Jimenez, and M. J. Cubison
Atmos. Chem. Phys., 14, 5073–5087,
S. Romakkaniemi, A. Jaatinen, A. Laaksonen, A. Nenes, and T. Raatikainen
Atmos. Meas. Tech., 7, 1377–1384,
A. Bougiatioti, I. Stavroulas, E. Kostenidou, P. Zarmpas, C. Theodosi, G. Kouvarakis, F. Canonaco, A. S. H. Prévôt, A. Nenes, S. N. Pandis, and N. Mihalopoulos
Atmos. Chem. Phys., 14, 4793–4807,
R. Morales Betancourt and A. Nenes
Atmos. Chem. Phys., 14, 4809–4826,
J. M. Livingston, J. Redemann, Y. Shinozuka, R. Johnson, P. B. Russell, Q. Zhang, S. Mattoo, L. Remer, R. Levy, L. Munchak, and S. Ramachandran
Atmos. Chem. Phys., 14, 2015–2038,
S. P. Burton, M. A. Vaughan, R. A. Ferrare, and C. A. Hostetler
Atmos. Meas. Tech., 7, 419–436,
S. Freitag, A. D. Clarke, S. G. Howell, V. N. Kapustin, T. Campos, V. L. Brekhovskikh, and J. Zhou
Atmos. Meas. Tech., 7, 107–128,
P. E. Saide, G. R. Carmichael, Z. Liu, C. S. Schwartz, H. C. Lin, A. M. da Silva, and E. Hyer
Atmos. Chem. Phys., 13, 10425–10444,
F. Patadia, R. A. Kahn, J. A. Limbacher, S. P. Burton, R. A. Ferrare, C. A. Hostetler, and J. W. Hair
Atmos. Chem. Phys., 13, 9525–9541,
M. Trail, A. P. Tsimpidi, P. Liu, K. Tsigaridis, Y. Hu, A. Nenes, and A. G. Russell
Geosci. Model Dev., 6, 1429–1445,
D. J. Diner, F. Xu, M. J. Garay, J. V. Martonchik, B. E. Rheingans, S. Geier, A. Davis, B. R. Hancock, V. M. Jovanovic, M. A. Bull, K. Capraro, R. A. Chipman, and S. C. McClain
Atmos. Meas. Tech., 6, 2007–2025,
A. D. Clarke, S. Freitag, R. M. C. Simpson, J. G. Hudson, S. G. Howell, V. L. Brekhovskikh, T. Campos, V. N. Kapustin, and J. Zhou
Atmos. Chem. Phys., 13, 7511–7529,
R. Blot, A. D. Clarke, S. Freitag, V. Kapustin, S. G. Howell, J. B. Jensen, L. M. Shank, C. S. McNaughton, and V. Brekhovskikh
Atmos. Chem. Phys., 13, 7263–7278,
L. A. Munchak, R. C. Levy, S. Mattoo, L. A. Remer, B. N. Holben, J. S. Schafer, C. A. Hostetler, and R. A. Ferrare
Atmos. Meas. Tech., 6, 1747–1759,
S. P. Burton, R. A. Ferrare, M. A. Vaughan, A. H. Omar, R. R. Rogers, C. A. Hostetler, and J. W. Hair
Atmos. Meas. Tech., 6, 1397–1412,
S. Lance, T. Raatikainen, T. B. Onasch, D. R. Worsnop, X.-Y. Yu, M. L. Alexander, M. R. Stolzenburg, P. H. McMurry, J. N. Smith, and A. Nenes
Atmos. Chem. Phys., 13, 5049–5062,
R. H. Moore, V. A. Karydis, S. L. Capps, T. L. Lathem, and A. Nenes
Atmos. Chem. Phys., 13, 4235–4251,
B. van Diedenhoven, B. Cairns, A. M. Fridlind, A. S. Ackerman, and T. J. Garrett
Atmos. Chem. Phys., 13, 3185–3203,
T. L. Lathem, A. J. Beyersdorf, K. L. Thornhill, E. L. Winstead, M. J. Cubison, A. Hecobian, J. L. Jimenez, R. J. Weber, B. E. Anderson, and A. Nenes
Atmos. Chem. Phys., 13, 2735–2756,
C. H. Twohy, J. R. Anderson, D. W. Toohey, M. Andrejczuk, A. Adams, M. Lytle, R. C. George, R. Wood, P. Saide, S. Spak, P. Zuidema, and D. Leon
Atmos. Chem. Phys., 13, 2541–2562,
M. Frosch, M. Bilde, A. Nenes, A. P. Praplan, Z. Jurányi, J. Dommen, M. Gysel, E. Weingartner, and U. Baltensperger
Atmos. Chem. Phys., 13, 2283–2297,
Y. C. Sud, D. Lee, L. Oreopoulos, D. Barahona, A. Nenes, and M. J. Suarez
Geosci. Model Dev., 6, 57–79,
Related subject area
Subject: Aerosols | Technique: Remote Sensing | Topic: Instruments and PlatformsMulti-star calibration in starphotometryThe Langley Ratio method, a new approach for transferring photometer calibration from direct sun measurementsMultiwavelength fluorescence lidar observations of smoke plumesContinuous observations from horizontally pointing lidar, weather parameters, and PM2.5: a pre-deployment assessment for monitoring radioactive dust in Fukushima, JapanEarth observations from the Moon's surface: dependence on lunar librationRelationship between the sub-micron fraction (SMF) and fine-mode fraction (FMF) in the context of AERONET retrievalsSystematic analysis of virga and its impact on surface particulate matter observationsSpectrometric fluorescence and Raman lidar: absolute calibration of aerosol fluorescence spectra and fluorescence correction of humidity measurementsThe polarimetric characteristics of dust with irregular shapes: evaluation of the spheroid model for single particlesThe eVe reference polarisation lidar system for the calibration and validation of the Aeolus L2A productEvaluation of aerosol microphysical, optical and radiative properties measured with a multiwavelength photometerPolarization lidar for detecting dust orientation: system design and calibrationAccuracy in starphotometryRethinking the correction for absorbing aerosols in the OMI- and TROPOMI-like surface UV algorithmsMie–Raman–fluorescence lidar observations of aerosols during pollen season in the north of FranceSatellite imagery and products of the 16–17 February 2020 Saharan Air Layer dust event over the eastern Atlantic: impacts of water vapor on dust detection and morphologyCombined use of Mie–Raman and fluorescence lidar observations for improving aerosol characterization: feasibility experimentSolar radiometer sensing of multi-year aerosol features over a tropical urban station: direct-Sun and inversion productsAn overview of and issues with sky radiometer technology and SKYNETScanning polarization lidar LOSA-M3: opportunity for research of crystalline particle orientation in the ice cloudsThe polarized Sun and sky radiometer SSARA: design, calibration, and application for ground-based aerosol remote sensingNocturnal aerosol optical depth measurements with modified sky radiometer POM-02 using the moon as a light sourceRelationship analysis of PM2.5 and boundary layer height using an aerosol and turbulence detection lidarMonitoring aerosols over Europe: an assessment of the potential benefit of assimilating the VIS04 measurements from the future MTG/FCI geostationary imagerThe impact of MISR-derived injection height initialization on wildfire and volcanic plume dispersion in the HYSPLIT modelThe instrument constant of sky radiometers (POM-02) – Part 1: Calibration constantThe instrument constant of sky radiometers (POM-02) – Part 2: Solid view angleDescription and applications of a mobile system performing on-road aerosol remote sensing and in situ measurementsRemote sensing of aerosols with small satellites in formation flightA study of the approaches used to retrieve aerosol extinction, as applied to limb observations made by OSIRIS and SCIAMACHYIncreased aerosol content in the atmosphere over Ukraine during summer 2010Experimental techniques for the calibration of lidar depolarization channels in EARLINETCalibration of the DSCOVR EPIC visible and NIR channels using MODIS Terra and Aqua data and EPIC lunar observationsUsing paraxial approximation to describe the optical setup of a typical EARLINET lidar systemCross-calibration of S-NPP VIIRS moderate-resolution reflective solar bands against MODIS Aqua over dark water scenesAerosol optical depth determination in the UV using a four-channel precision filter radiometerA new zenith-looking narrow-band radiometer-based system (ZEN) for dust aerosol optical depth monitoringAerosol absorption retrieval at ultraviolet wavelengths in a complex environment1064 nm rotational Raman lidar for particle extinction and lidar-ratio profiling: cirrus case studyAbout the effects of polarising optics on lidar signals and the Δ90 calibrationRecommendations for processing atmospheric attenuated backscatter profiles from Vaisala CL31 ceilometersAn empirical method to correct for temperature-dependent variations in the overlap function of CHM15k ceilometersMonitoring and tracking the trans-Pacific transport of aerosols using multi-satellite aerosol optical depth compositesThe automated multiwavelength Raman polarization and water-vapor lidar PollyXT: the neXT generationProfiling the PM2.5 mass concentration vertical distribution in the boundary layerThe Aerosol Limb Imager: acousto-optic imaging of limb-scattered sunlight for stratospheric aerosol profiling
Liviu Ivănescu and Norman T. O'Neill
The starphotometers complex infrastructure prohibits calibration campaigns. On-site calibration procedures appear as the only practical solution. A multi-star approach overcomes site-specific sky stability problems. Star selection strategies were proposed for mitigating some sources of errors. Data processing strategies and instrument design improvements appear necessary.
Antonio Fernando Almansa, África Barreto, Natalia Kouremeti, Ramiro González, Akriti Masoom, Carlos Toledano, Julian Gröbner, Rosa Delia García, Yenny González, Stelios Kazadzis, Stephane Victori, Óscar Álvarez, Virgilio Carreño, Victoria Eugenia Cachorro, and Emilio Cuevas
Atmos. Meas. Tech. Discuss.,
Revised manuscript accepted for AMTShort summary
This paper applies sun-photometer synergies to improve calibration transference between different sun-photometers and also enhance their quality assurance and quality control. We have validated this technique using different instrumentation, the WMO-GAW and NASA-AERONET references, under different aerosol regimes using the standard Langley calibration method as a reference.
Igor Veselovskii, Nikita Kasianik, Mikhail Korenskii, Qiaoyun Hu, Philippe Goloub, Thierry Podvin, and Dong Liu
Atmos. Meas. Tech., 16, 2055–2065,Short summary
A five-channel fluorescence lidar was developed for the study of atmospheric aerosol. The fluorescence spectrum induced by 355 nm laser emission is analyzed in five spectral intervals, namely 438 and 29, 472 and 32, 513 and 29, 560 and 40, and 614 and 54 nm. This lidar system was operated during strong forest fires. Our results demonstrate that, for urban aerosol, the maximal fluorescence backscattering is observed at 472 nm, while for smoke, the spectrum is shifted toward longer wavelengths.
Nofel Lagrosas, Kosuke Okubo, Hitoshi Irie, Yutaka Matsumi, Tomoki Nakayama, Yutaka Sugita, Takashi Okada, and Tatsuo Shiina
This work examines the near-ground aerosol-weather relationship from seven-month continuous lidar and weather observations in Chiba, Japan. The optical parameters from lidar data are compared with weather parameters to understand and quantify aerosol-weather relationship and how these optical parameters are affected by weather and season. The results provide insights into analyzing optical properties of radioactive aerosols when the lidar system is continuously operated in a radioactive area.
Nick Gorkavyi, Nickolay Krotkov, and Alexander Marshak
Atmos. Meas. Tech., 16, 1527–1537,Short summary
The article discusses topical issues of the visible (libration) motion of the Earth in the sky of the Moon in a rectangle measuring 13.4° × 15.8°. On the one hand, the librations of the Moon make these observations difficult. On the other hand, they can be used as a natural scanning mechanism for cameras and spectroscopes mounted on a fixed platform on the surface of the Moon.
Norman T. O'Neill, Keyvan Ranjbar, Liviu Ivănescu, Thomas F. Eck, Jeffrey S. Reid, David M. Giles, Daniel Pérez-Ramírez, and Jai Prakash Chaubey
Atmos. Meas. Tech., 16, 1103–1120,Short summary
Aerosols are atmospheric particles that vary in size (radius) from a fraction of a micrometer (µm) to around 20 µm. They tend to be either smaller than 1 µm (like smoke or pollution) or larger than 1 µm (like dust or sea salt). Their optical effect (scattering and absorbing sunlight) can be divided into FM (fine-mode) and CM (coarse-mode) parts using a cutoff radius around 1 µm or a spectral (color) technique. We present and validate a theoretical link between the types of FM and CM divisions.
Nakul N. Karle, Ricardo K. Sakai, Rosa M. Fitzgerald, Charles Ichoku, Fernando Mercado, and William R. Stockwell
Atmos. Meas. Tech., 16, 1073–1085,Short summary
Extensive virga research is uncommon, even though it is a common phenomenon. A systematic method was developed to characterize virga using available datasets. In total, 50 virga events were observed, appearing only during a specific time of the year, revealing a seasonal pattern. These virga events were identified and classified, and their impact on surface PM measurements was investigated. A more detailed examination of the selected events reveals that virga impacts regional air quality.
Jens Reichardt, Oliver Behrendt, and Felix Lauermann
Atmos. Meas. Tech., 16, 1–13,Short summary
The UVA spectrometer is the latest instrumental addition to the spectrometric fluorescence and Raman lidar RAMSES. The redesigned receiver and the data analysis of the fluorescence measurement are described. Furthermore, the effect of aerosol fluorescence on humidity measurements is studied. It turns out that Raman lidars equipped with a spectrometer show superior performance over those with one discrete fluorescence detection channel only. The cause is variability in the fluorescence spectrum.
Jie Luo, Zhengqiang Li, Cheng Fan, Hua Xu, Ying Zhang, Weizhen Hou, Lili Qie, Haoran Gu, Mengyao Zhu, Yinna Li, and Kaitao Li
Atmos. Meas. Tech., 15, 2767–2789,Short summary
A single model is difficult to represent various shapes of dust. We proposed a tunable model to represent dust with various shapes. Two tunable parameters were used to represent the effects of the erosion degree and binding forces from the mass center. Thus, the model can represent various dust shapes by adjusting the tunable parameters. Besides, the applicability of the spheroid model in calculating the optical properties and polarimetric characteristics is evaluated.
Peristera Paschou, Nikolaos Siomos, Alexandra Tsekeri, Alexandros Louridas, George Georgoussis, Volker Freudenthaler, Ioannis Binietoglou, George Tsaknakis, Alexandros Tavernarakis, Christos Evangelatos, Jonas von Bismarck, Thomas Kanitz, Charikleia Meleti, Eleni Marinou, and Vassilis Amiridis
Atmos. Meas. Tech., 15, 2299–2323,Short summary
The eVe lidar delivers quality-assured aerosol and cloud optical properties according to the standards of ACTRIS. It is a mobile reference system for the validation of the ESA's Aeolus satellite mission (L2 aerosol and cloud products). eVe provides linear and circular polarisation measurements with Raman capabilities. Here, we describe the system design, the polarisation calibration techniques, and the software for the retrieval of the optical products.
Yu Zheng, Huizheng Che, Yupeng Wang, Xiangao Xia, Xiuqing Hu, Xiaochun Zhang, Jun Zhu, Jibiao Zhu, Hujia Zhao, Lei Li, Ke Gui, and Xiaoye Zhang
Atmos. Meas. Tech., 15, 2139–2158,Short summary
Ground-based observations of aerosols and aerosol data verification is important for satellite and climate model modification. Here we present an evaluation of aerosol microphysical, optical and radiative properties measured using a multiwavelength photometer with a highly integrated design and smart control performance. The validation of this product is discussed in detail using AERONET as a reference. This work contributes to reducing AOD uncertainties in China and combating climate change.
Alexandra Tsekeri, Vassilis Amiridis, Alexandros Louridas, George Georgoussis, Volker Freudenthaler, Spiros Metallinos, George Doxastakis, Josef Gasteiger, Nikolaos Siomos, Peristera Paschou, Thanasis Georgiou, George Tsaknakis, Christos Evangelatos, and Ioannis Binietoglou
Atmos. Meas. Tech., 14, 7453–7474,Short summary
Dust orientation in the Earth's atmosphere has been an ongoing investigation in recent years, and its potential proof will be a paradigm shift for dust remote sensing. We have designed and developed a polarization lidar that provides direct measurements of dust orientation, as well as more detailed information of the particle microphysics. We provide a description of its design as well as its first measurements.
Liviu Ivănescu, Konstantin Baibakov, Norman T. O'Neill, Jean-Pierre Blanchet, and Karl-Heinz Schulz
Atmos. Meas. Tech., 14, 6561–6599,Short summary
Starphotometry seeks to provide accurate measures of nocturnal optical depth (OD). It is driven by a need to characterize aerosols and their radiative forcing effects during a very data-sparse period. A sub-0.01 OD error is required to adequately characterize key aerosol parameters. We found approaches for sufficiently mitigating errors to achieve the 0.01 standard. This renders starphotometry the equal of daytime techniques and opens the door to exploiting its distinct star-pointing advantages.
Antti Arola, William Wandji Nyamsi, Antti Lipponen, Stelios Kazadzis, Nickolay A. Krotkov, and Johanna Tamminen
Atmos. Meas. Tech., 14, 4947–4957,Short summary
Methods to estimate surface UV radiation from satellite measurements offer the only means to obtain global coverage, and the development of satellite-based UV algorithms has been ongoing since the early 1990s. One of the main challenges in this development has been how to account for the overall effect of absorption by atmospheric aerosols. One such method was suggested roughly a decade ago, and in this study we propose further improvements for this kind of approach.
Igor Veselovskii, Qiaoyun Hu, Philippe Goloub, Thierry Podvin, Marie Choël, Nicolas Visez, and Mikhail Korenskiy
Atmos. Meas. Tech., 14, 4773–4786,Short summary
The multiwavelength Mie–Raman–fluorescence lidar of the University of Lille was used to characterize aerosols during the pollen season in the north of France for the period March–June 2020. The results of observations demonstrate that the presence of pollen grains in aerosol mixtures leads to an increase in the depolarization ratio and to the enhancement of the fluorescence backscattering.
Lewis Grasso, Daniel Bikos, Jorel Torres, John F. Dostalek, Ting-Chi Wu, John Forsythe, Heather Q. Cronk, Curtis J. Seaman, Steven D. Miller, Emily Berndt, Harry G. Weinman, and Kennard B. Kasper
Atmos. Meas. Tech., 14, 1615–1634,Short summary
This study uses geostationary imagery to detect dust. This research was done to demonstrate the ability of dust detection over ocean surfaces in a dry atmosphere.
Igor Veselovskii, Qiaoyun Hu, Philippe Goloub, Thierry Podvin, Mikhail Korenskiy, Olivier Pujol, Oleg Dubovik, and Anton Lopatin
Atmos. Meas. Tech., 13, 6691–6701,Short summary
To study the feasibility of a fluorescence lidar for aerosol characterization, the fluorescence channel is added to the multiwavelength Mie-Raman lidar of Lille University. A part of the fluorescence spectrum is selected by the interference filter of 44 nm bandwidth centered at 466 nm. Such an approach has demonstrated high sensitivity, allowing fluorescence signals from weak aerosol layers to be detected. The technique can also be used for monitoring the aerosol inside the cloud layers.
Katta Vijayakumar, Panuganti C. S. Devara, Sunil M. Sonbawne, David M. Giles, Brent N. Holben, Sarangam Vijaya Bhaskara Rao, and Chalicheemalapalli K. Jayasankar
Atmos. Meas. Tech., 13, 5569–5593,Short summary
The direct-Sun and inversion products of urban atmospheric aerosols, obtained from a Cimel Sun–sky radiometer in Pune, India, under the AERONET program since October 2004, have been reported in this paper. The mean seasonal variations in AOD from cloud-free days indicated greater values during the monsoon season, revealing dominance of hygroscopic aerosols over the station. Such results are sparse in India and are important for estimating aerosol radiative forcing and validating climate models.
Teruyuki Nakajima, Monica Campanelli, Huizheng Che, Victor Estellés, Hitoshi Irie, Sang-Woo Kim, Jhoon Kim, Dong Liu, Tomoaki Nishizawa, Govindan Pandithurai, Vijay Kumar Soni, Boossarasiri Thana, Nas-Urt Tugjsurn, Kazuma Aoki, Sujung Go, Makiko Hashimoto, Akiko Higurashi, Stelios Kazadzis, Pradeep Khatri, Natalia Kouremeti, Rei Kudo, Franco Marenco, Masahiro Momoi, Shantikumar S. Ningombam, Claire L. Ryder, Akihiro Uchiyama, and Akihiro Yamazaki
Atmos. Meas. Tech., 13, 4195–4218,Short summary
This paper overviews the progress in sky radiometer technology and the development of the network called SKYNET. It is found that the technology has produced useful on-site calibration methods, retrieval algorithms, and data analyses from sky radiometer observations of aerosol, cloud, water vapor, and ozone. The paper also discusses current issues of SKYNET to provide better information for the community.
Grigorii P. Kokhanenko, Yurii S. Balin, Marina G. Klemasheva, Sergei V. Nasonov, Mikhail M. Novoselov, Iogannes E. Penner, and Svetlana V. Samoilova
Atmos. Meas. Tech., 13, 1113–1127,Short summary
Cirrus clouds consist of crystals (plates, needles) that can orient themselves in space as a result of free fall. This leads to the appearance of various types of optical halo and to specular reflection of solar radiation. The presence of such particles significantly affects the passage of thermal radiation through the mid- and high-level ice clouds. Using the properties of polarization, a scanning lidar makes it possible to identify cloud areas with oriented crystals.
Hans Grob, Claudia Emde, Matthias Wiegner, Meinhard Seefeldner, Linda Forster, and Bernhard Mayer
Atmos. Meas. Tech., 13, 239–258,Short summary
Polarimetry has been established as an enhancement to classical photometry in aerosol remote sensing over the past years. We propose a fast and exact radiometric and polarimetric calibration method for polarized photometers. Additionally, a technique for correcting an alt-azimuthal mount is introduced. These methods are applied to measurements obtained with our SSARA instrument during the A-LIFE field campaign. For 2 d, the data are subjected to an inversion of aerosol optical properties.
Akihiro Uchiyama, Masataka Shiobara, Hiroshi Kobayashi, Tsuneo Matsunaga, Akihiro Yamazaki, Kazunori Inei, Kazuhiro Kawai, and Yoshiaki Watanabe
Atmos. Meas. Tech., 12, 6465–6488,Short summary
The majority of aerosol data are obtained from daytime measurements using the Sun as a light source, and there are few datasets available for studying nighttime aerosol characteristics. To estimate the aerosol optical depth (AOD) during the nighttime using the moon as a light source, a radiometer for the daytime was modified, and a new calibration method was developed. As a result, the estimations of the nighttime AOD were made with the same degree of precision and accuracy during the daytime.
Chong Wang, Mingjiao Jia, Haiyun Xia, Yunbin Wu, Tianwen Wei, Xiang Shang, Chengyun Yang, Xianghui Xue, and Xiankang Dou
Atmos. Meas. Tech., 12, 3303–3315,Short summary
To investigate the relationship between BLH and air pollution under different conditions, a compact micro-pulse lidar integrating both direct-detection lidar and coherent Doppler wind lidar is built. Evolution of atmospheric boundary layer height (BLH), aerosol layer and fine structure in cloud base are well retrieved. Negative correlation exists between BLH and PM2.5. Different trends show that the relationship between PM2.5 and BLH should be considered in different boundary layer categories.
Maxence Descheemaecker, Matthieu Plu, Virginie Marécal, Marine Claeyman, Francis Olivier, Youva Aoun, Philippe Blanc, Lucien Wald, Jonathan Guth, Bojan Sič, Jérôme Vidot, Andrea Piacentini, and Béatrice Josse
Atmos. Meas. Tech., 12, 1251–1275,Short summary
The future Flexible Combined Imager (FCI) on board MeteoSat Third Generation is expected to improve the detection and the quantification of aerosols. The study assesses the potential of FCI/VIS04 channel for monitoring air pollution in Europe. An observing system simulation experiment in MOCAGE is developed, and they show a large positive impact of the assimilation over a 4-month period and particularly during a severe pollution episode. The added value of geostationary data is also assessed.
Charles J. Vernon, Ryan Bolt, Timothy Canty, and Ralph A. Kahn
Atmos. Meas. Tech., 11, 6289–6307,Short summary
The height that aerosols are injected into the atmosphere can significantly impact the dispersion of aerosol plumes. We use direct observations from the MISR instrument to determine aerosol injection height and constrain the HYSPLIT Dispersion model with these data. We have shown that the nominal plume-rise calculation within HYSPLIT tends to underestimate injection heights of wildfires and that simulations constrained with MISR injection height can show better agreement with MODIS observations.
Akihiro Uchiyama, Tsuneo Matsunaga, and Akihiro Yamazaki
Atmos. Meas. Tech., 11, 5363–5388,Short summary
Atmospheric aerosols are an important constituent of the atmosphere. Measurement networks using radiometers such as SKYNET have been developed. There are two constants that we must determine to make accurate measurements. One of them is the calibration constant. The accuracy of the current method to determine this was investigated and the new method for water vapor and near-infrared channels was developed. Utilizing the results of this paper, SKYNET measurement data will become more reliable.
Akihiro Uchiyama, Tsuneo Matsunaga, and Akihiro Yamazaki
Atmos. Meas. Tech., 11, 5389–5402,Short summary
Atmospheric aerosols are an important constituent of the atmosphere. Measurement networks using radiometers such as SKYNET have been developed. There are two constants that we must determine. One of them is the solid view angle (SVA) of the radiometer. The problems related to SVA were investigated. It was shown that the conventional method can cause a systematic underestimation, and an improved method was proposed. Utilizing the results of this paper, SKYNET data will become more reliable.
Ioana Elisabeta Popovici, Philippe Goloub, Thierry Podvin, Luc Blarel, Rodrigue Loisil, Florin Unga, Augustin Mortier, Christine Deroo, Stéphane Victori, Fabrice Ducos, Benjamin Torres, Cyril Delegove, Marie Choël, Nathalie Pujol-Söhne, and Christophe Pietras
Atmos. Meas. Tech., 11, 4671–4691,Short summary
This paper aims to show the potential of an instrumented mobile platform, performing on-road remote sensing and in situ measurements, to derive aerosol properties. It is distinguished from other transportable platforms through its ability to perform measurements during movement. Its reduced size, versatility and great flexibility makes it suitable for following sudden aerosol events and for validating satellite measurements and model simulations.
Kirk Knobelspiesse and Sreeja Nag
Atmos. Meas. Tech., 11, 3935–3954,Short summary
We test if small satellites flying in formation can be used for multi-angle aerosol remote sensing. So far, this has only been done with multiple views on one satellite. Single-view angle satellites flying in formation are a technically feasible alternative, although with different geometries. Using Bayesian information content analysis, we find such satellites equally capable. For aerosol remote sensing, the number of viewing angles is the most important.
Landon A. Rieger, Elizaveta P. Malinina, Alexei V. Rozanov, John P. Burrows, Adam E. Bourassa, and Doug A. Degenstein
Atmos. Meas. Tech., 11, 3433–3445,Short summary
This paper compares aerosol extinction records from two limb scattering instruments, OSIRIS and SCIAMACHY, to that from the occultation instrument SAGE II. Differences are investigated through modelling and retrieval studies and important sources of systematic errors are quantified. It is found that the largest biases come from uncertainties in the aerosol size distribution and the aerosol particle concentration at altitudes above 30 km.
Evgenia Galytska, Vassyl Danylevsky, René Hommel, and John P. Burrows
Atmos. Meas. Tech., 11, 2101–2118,Short summary
This research assesses the influence of biomass burning during forest fires throughout summer 2010 on aerosol load over Ukraine, the European territory of Russia (ETR) and Eastern Europe. We apply and compare ground-based and satellite measurements to determine aerosol content, dynamics, and properties. With the application of modeling techniques (HYSPLIT), we show that the maximum AOD in August 2010 over Ukraine was caused by particle transport from the forest fires in the ETR.
Livio Belegante, Juan Antonio Bravo-Aranda, Volker Freudenthaler, Doina Nicolae, Anca Nemuc, Dragos Ene, Lucas Alados-Arboledas, Aldo Amodeo, Gelsomina Pappalardo, Giuseppe D'Amico, Francesco Amato, Ronny Engelmann, Holger Baars, Ulla Wandinger, Alexandros Papayannis, Panos Kokkalis, and Sérgio N. Pereira
Atmos. Meas. Tech., 11, 1119–1141,Short summary
This paper presents different depolarization calibration procedures used to improve the quality of the depolarization data. The results illustrate a significant improvement of the depolarization lidar products for all the selected EARLINET lidar instruments. The calibrated volume and particle depolarization profiles at 532 nm show values that fall within a range that is accepted in the literature. The depolarization accuracy estimate at 532 nm is better than ±0.03 for all cases.
Igor V. Geogdzhayev and Alexander Marshak
Atmos. Meas. Tech., 11, 359–368,Short summary
The unique Earth view of the Deep Space Climate Observatory (DSCOVR) Earth Polychromatic Imaging Camera (EPIC) orbiting at the point of equal attraction from the Earth and the Sun can significantly augment the low-orbit remote sensing of aerosols, clouds and gases. We derive the relationship between the digital counts and the reflected sunlight intensity for some EPIC channels using collocated Earth views from EPIC and Moderate Resolution Imaging Spectroradiometer (MODIS) and EPIC moon views.
Atmos. Meas. Tech., 10, 3103–3115,Short summary
The mathematical formulation for the optical setup of a typical EARLINET lidar system is given here. The equations describing a lidar system from the emitted laser beam to the projection of the telescope aperture on the final receiving unit (i.e., photomultiplier or photodiode) are presented, based on paraxial approximation and a geometric optics approach. The evaluation of the formulation is performed with ray-tracing simulations on a real system.
Andrew M. Sayer, N. Christina Hsu, Corey Bettenhausen, Robert E. Holz, Jaehwa Lee, Greg Quinn, and Paolo Veglio
Atmos. Meas. Tech., 10, 1425–1444,Short summary
The satellite instrument VIIRS is being used to carry on observations of the Earth made by older satellites like MODIS. Data sets created from these satellite observations depend on the quality of the satellite instruments' calibration. This paper describes a comparison between the calibration of these two sensors. MODIS is believed to be more reliable and so VIIRS is corrected to bring it in line with MODIS. These corrections are shown to improve the quality of VIIRS aerosol data.
Thomas Carlund, Natalia Kouremeti, Stelios Kazadzis, and Julian Gröbner
Atmos. Meas. Tech., 10, 905–923,Short summary
Aerosols play an important role in atmospheric processes. Aerosol optical depth is the most common measure of columnar aerosol load. We present a sunphotometer called UVPFR that is able to measure aerosol optical depth in the ultraviolet range, including the calibration, characterization and validation of the instrument/measurements. The instrument will serve as a reference on the intercalibration of Brewer spectrophotometers that are also able to measure aerosol optical depth in the UV region.
A. Fernando Almansa, Emilio Cuevas, Benjamín Torres, África Barreto, Rosa D. García, Victoria E. Cachorro, Ángel M. de Frutos, César López, and Ramón Ramos
Atmos. Meas. Tech., 10, 565–579,Short summary
This study presents a new zenith-looking narrow-band radiometer-based system (ZEN), conceived for dust aerosol optical depth (AOD) monitoring. The ZEN system comprises a robust and automated radiometer (ZEN-R41), and a lookup table methodology for AOD retrieval (ZEN-LUT). Our results suggest that ZEN is a suitable system to fill the current observational gaps and to complement observations performed by sun-photometer networks in order to improve mineral dust monitoring in remote locations.
Stelios Kazadzis, Panagiotis Raptis, Natalia Kouremeti, Vassilis Amiridis, Antti Arola, Evangelos Gerasopoulos, and Gregory L. Schuster
Atmos. Meas. Tech., 9, 5997–6011,Short summary
Aerosols play an important role in the Earth's climate. One of the main aerosol properties is the single scattering albedo which is a measure of the aerosol absorption. In this work we have presented a method to retrieve this aerosol property in the ultraviolet and we presented the results for measurements at the urban environment of Athens, Greece. We show that the spectral dependence of the aerosol absorption in the VIS–IR and the UV range depends on the aerosol composition and type.
Moritz Haarig, Ronny Engelmann, Albert Ansmann, Igor Veselovskii, David N. Whiteman, and Dietrich Althausen
Atmos. Meas. Tech., 9, 4269–4278,
Atmos. Meas. Tech., 9, 4181–4255,
Simone Kotthaus, Ewan O'Connor, Christoph Münkel, Cristina Charlton-Perez, Martial Haeffelin, Andrew M. Gabey, and C. Sue B. Grimmond
Atmos. Meas. Tech., 9, 3769–3791,Short summary
Ceilometers lidars are useful to study clouds, aerosol layers and atmospheric boundary layer structures. As sensor optics and acquisition algorithms can strongly influence the observations, sensor specifics need to be incorporated into the physical interpretation. Here, recommendations are made for the operation and processing of profile observations from the widely deployed Vaisala CL31 ceilometer. Proposed corrections are shown to increase data quality and even data availability at times.
Maxime Hervo, Yann Poltera, and Alexander Haefele
Atmos. Meas. Tech., 9, 2947–2959,Short summary
Imperfections in a lidar's overlap function lead to artefacts in the lidar (Light Detection and Ranging) signals. These artefacts can erroneously be interpreted as an aerosol gradient or, in extreme cases, as a cloud base leading to false cloud detection. In this study an algorithm is presented to correct such artefacts. The algorithm is completely automatic and does not require any intervention on site. It is therefore suited for use in large automatic lidar networks.
Aaron R. Naeger, Pawan Gupta, Bradley T. Zavodsky, and Kevin M. McGrath
Atmos. Meas. Tech., 9, 2463–2482,Short summary
In this study, we merge aerosol information from multiple satellite sensors on board low-earth orbiting (LEO) and geostationary (GEO) platforms in order to provide a more comprehensive understanding of the spatial distribution of aerosols compared to when only using single sensors as is commonly done. Our results show that merging aerosol information from LEO and GEO platforms can be very useful, which paves the way for applications to the more advanced next-generation of satellites.
Ronny Engelmann, Thomas Kanitz, Holger Baars, Birgit Heese, Dietrich Althausen, Annett Skupin, Ulla Wandinger, Mika Komppula, Iwona S. Stachlewska, Vassilis Amiridis, Eleni Marinou, Ina Mattis, Holger Linné, and Albert Ansmann
Atmos. Meas. Tech., 9, 1767–1784,Short summary
The atmospheric science community demands for autonomous and quality-assured vertically resolved measurements of aerosol and cloud properties. For this purpose, a portable lidar called Polly was developed at TROPOS in 2003. This lidar type was continuously improved with gained experience from EARLINET, worldwide field campaigns, and institute collaborations within the last 10 years. We present recent changes to the setup of our portable multiwavelength Raman and polarization lidar PollyXT.
Zongming Tao, Zhenzhu Wang, Shijun Yang, Huihui Shan, Xiaomin Ma, Hui Zhang, Sugui Zhao, Dong Liu, Chenbo Xie, and Yingjian Wang
Atmos. Meas. Tech., 9, 1369–1376,Short summary
A new measurement technology of PM2.5 mass concentration profile near ground is addressed using a CCD side-scatter lidar and a PM2.5 detector. The PM2.5 mass concentration profile can be built upon the vertical distribution of the extinction coefficient for aerosol. The PM2.5 is always loading in the planet boundary layer with a complex muti-layer structure. The new method for PM2.5 mass concentration profile is useful for improving our understanding of air quality and atmospheric environment.
B. J. Elash, A. E. Bourassa, P. R. Loewen, N. D. Lloyd, and D. A. Degenstein
Atmos. Meas. Tech., 9, 1261–1277,