Articles | Volume 11, issue 3
https://doi.org/10.5194/amt-11-1377-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/amt-11-1377-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Raindrop fall velocities from an optical array probe and 2-D video disdrometer
Viswanathan Bringi
CORRESPONDING AUTHOR
Department of Electrical and Computer Engineering, Colorado
State University, Fort Collins, Colorado, USA
Merhala Thurai
Department of Electrical and Computer Engineering, Colorado
State University, Fort Collins, Colorado, USA
Darrel Baumgardner
Droplet Measurements Technologies, Longmont, Colorado, USA
Related authors
Viswanathan Bringi, Kumar Vijay Mishra, Merhala Thurai, Patrick C. Kennedy, and Timothy H. Raupach
Atmos. Meas. Tech., 13, 4727–4750, https://doi.org/10.5194/amt-13-4727-2020, https://doi.org/10.5194/amt-13-4727-2020, 2020
Short summary
Short summary
The raindrop size distribution and its moments are fundamental in many areas, such as radar measurement of rainfall using polarimetry and numerical modeling of the microphysical processes of rain formation and evolution. We develop a technique which uses advanced radar measurements and complete drop size distributions using two collocated instruments to retrieve the lower-order moments such as total drop concentration and rain water content. We demonstrate a proof-of-concept using a case study.
Merhala Thurai, Michael Schönhuber, Günter Lammer, and Viswanathan Bringi
Adv. Sci. Res., 16, 95–101, https://doi.org/10.5194/asr-16-95-2019, https://doi.org/10.5194/asr-16-95-2019, 2019
Short summary
Short summary
Raindrop shapes and fall velocities are presented for two high-wind/turbulent events. Results show strong gusts, directional wind shifts and/or inferred high turbulence intensity are correlated with reduced fall speeds, reaching values ~ 25–30 % less than the expected values, i.e. sub-terminal fall speeds. Significant percentage of asymmetric drops deviating from the most probable ax-isymmetric shapes was also detected during high turbulent intensities.
Mahen Konwar, Benjamin Werden, Edward C. Fortner, Sudarsan Bera, Mercy Varghese, Subharthi Chowdhuri, Kurt Hibert, Philip Croteau, John Jayne, Manjula Canagaratna, Neelam Malap, Sandeep Jayakumar, Shivsai A. Dixit, Palani Murugavel, Duncan Axisa, Darrel Baumgardner, Peter F. DeCarlo, Doug R. Worsnop, and Thara Prabhakaran
Atmos. Meas. Tech., 17, 2387–2400, https://doi.org/10.5194/amt-17-2387-2024, https://doi.org/10.5194/amt-17-2387-2024, 2024
Short summary
Short summary
In a warm cloud seeding experiment hygroscopic particles are released to alter cloud processes to induce early raindrops. During the Cloud–Aerosol Interaction and Precipitation Enhancement Experiment, airborne mini aerosol mass spectrometers analyse the particles on which clouds form. The seeded clouds showed higher concentrations of chlorine and potassium, the oxidizing agents of flares. Small cloud droplet concentrations increased, and seeding particles were detected in deep cloud depths.
Bighnaraj Sarangi, Darrel Baumgardner, Ana Isabel Calvo, Benjamin Bolaños-Rosero, Roberto Fraile, Alberto Rodríguez-Fernández, Delia Fernández-González, Carlos Blanco-Alegre, Cátia Gonçalves, Estela D. Vicente, and Olga L. Mayol Bracero
EGUsphere, https://doi.org/10.5194/egusphere-2024-446, https://doi.org/10.5194/egusphere-2024-446, 2024
Short summary
Short summary
Measurements of fluorescing aerosol particle properties have been made during two major African dust events, one over the island of Puerto Rico and the other over the city of León, Spain The measurements were with two Wideband Integrated Bioaerosol Spectrometers. A significant change in the background aerosol properties, at both locations, is observed when the dust is in the respective regions.
Bighnaraj Sarangi, Darrel Baumgardner, Benjamin Bolaños-Rosero, and Olga L. Mayol-Bracero
Atmos. Chem. Phys., 22, 9647–9661, https://doi.org/10.5194/acp-22-9647-2022, https://doi.org/10.5194/acp-22-9647-2022, 2022
Short summary
Short summary
Here, the fluorescent characteristics and cloud-forming efficiency of aerosols at an urban site in Puerto Rico are discussed. The results from this pilot study highlight the capabilities of ultraviolet-induced fluorescence (UV-IF) measurements for characterizing the properties of fluorescing aerosol particles, as they relate to the daily evolution of primary biological aerosol particles. This work has established a database of measurements on which future, longer-term studies will be initiated.
Graciela B. Raga, Darrel Baumgardner, Blanca Rios, Yanet Díaz-Esteban, Alejandro Jaramillo, Martin Gallagher, Bastien Sauvage, Pawel Wolff, and Gary Lloyd
Atmos. Chem. Phys., 22, 2269–2292, https://doi.org/10.5194/acp-22-2269-2022, https://doi.org/10.5194/acp-22-2269-2022, 2022
Short summary
Short summary
The In-Service Aircraft for a Global Observing System (IAGOS) is a small fleet of commercial aircraft that carry a suite of meteorological, gas, aerosol, and cloud sensors and have been measuring worldwide for almost 9 years, since late 2011. Extreme ice events (EIEs) have been identified from the IAGOS cloud measurements and linked to surface emissions for biomass and fossil fuel consumption. The results reported here are highly relevant for climate change and flight operations forecasting.
Elvis Torres-Delgado, Darrel Baumgardner, and Olga L. Mayol-Bracero
Atmos. Chem. Phys., 21, 18011–18027, https://doi.org/10.5194/acp-21-18011-2021, https://doi.org/10.5194/acp-21-18011-2021, 2021
Short summary
Short summary
African dust aerosols can travel thousands of kilometers and reach the Caribbean and other places, where they can serve as ice and cloud condensation nuclei and alter precipitation patterns. Cloud microphysical properties (droplet number and size) were measured in a Caribbean tropical montane cloud forest along with models and satellite products. The results of the study suggest that meteorology and air mass history are more important for cloud processes than aerosols transported from Africa.
Merhala Thurai, Viswanathan Bringi, Patrick Gatlin, and Mathew Wingo
Adv. Sci. Res., 18, 33–39, https://doi.org/10.5194/asr-18-33-2021, https://doi.org/10.5194/asr-18-33-2021, 2021
Short summary
Short summary
Fall velocities of rain drops are reported for 2–3 mm drop diameters for several different turbulent intensities. The fall velocities are measured by 2D video disdrometers and the turbulence intensities by 100 Hz sonic anemometer. The findings are, (i) the mean fall speed decreases with increasing turbulent intensity, and (ii) the standard deviation increases with increase in the rms of the air velocity fluctuations.
Fernanda Córdoba, Carolina Ramírez-Romero, Diego Cabrera, Graciela B. Raga, Javier Miranda, Harry Alvarez-Ospina, Daniel Rosas, Bernardo Figueroa, Jong Sung Kim, Jacqueline Yakobi-Hancock, Talib Amador, Wilfrido Gutierrez, Manuel García, Allan K. Bertram, Darrel Baumgardner, and Luis A. Ladino
Atmos. Chem. Phys., 21, 4453–4470, https://doi.org/10.5194/acp-21-4453-2021, https://doi.org/10.5194/acp-21-4453-2021, 2021
Short summary
Short summary
Most precipitation from deep clouds over the continents and in the intertropical convergence zone is strongly influenced by the presence of ice crystals whose formation requires the presence of aerosol particles. In the present study, the ability of three different aerosol types (i.e., marine aerosol, biomass burning, and African dust) to facilitate ice particle formation was assessed in the Yucatán Peninsula, Mexico.
Carolina Ramírez-Romero, Alejandro Jaramillo, María F. Córdoba, Graciela B. Raga, Javier Miranda, Harry Alvarez-Ospina, Daniel Rosas, Talib Amador, Jong Sung Kim, Jacqueline Yakobi-Hancock, Darrel Baumgardner, and Luis A. Ladino
Atmos. Chem. Phys., 21, 239–253, https://doi.org/10.5194/acp-21-239-2021, https://doi.org/10.5194/acp-21-239-2021, 2021
Short summary
Short summary
Field measurements were conducted to confirm the arrival of African dust on the Yucatàn Peninsula. Aerosol particles were monitored at ground level by different online and off-line sensors. Several particulate matter peaks were observed with a relative increase in their levels of up to 500 % with respect to background conditions. Based on the chemical composition, back trajectories, vertical profiles, reanalysis, and satellite images, it was found that the peaks are linked to African dust.
Viswanathan Bringi, Kumar Vijay Mishra, Merhala Thurai, Patrick C. Kennedy, and Timothy H. Raupach
Atmos. Meas. Tech., 13, 4727–4750, https://doi.org/10.5194/amt-13-4727-2020, https://doi.org/10.5194/amt-13-4727-2020, 2020
Short summary
Short summary
The raindrop size distribution and its moments are fundamental in many areas, such as radar measurement of rainfall using polarimetry and numerical modeling of the microphysical processes of rain formation and evolution. We develop a technique which uses advanced radar measurements and complete drop size distributions using two collocated instruments to retrieve the lower-order moments such as total drop concentration and rain water content. We demonstrate a proof-of-concept using a case study.
Lester Alfonso, Graciela B. Raga, and Darrel Baumgardner
Atmos. Chem. Phys., 19, 14917–14932, https://doi.org/10.5194/acp-19-14917-2019, https://doi.org/10.5194/acp-19-14917-2019, 2019
Short summary
Short summary
The aim of this paper is to find some observational evidence of gel formation in clouds, by analyzing the distribution of the largest droplet at an early stage of cloud formation, and to show that the mass of the gel (
lucky droplet) is a mixture of Gaussian and Gumbel distributions. The results obtained may help advance the understanding of precipitation formation and are a novel application of the theory of critical phenomena in cloud physics.
Merhala Thurai, Michael Schönhuber, Günter Lammer, and Viswanathan Bringi
Adv. Sci. Res., 16, 95–101, https://doi.org/10.5194/asr-16-95-2019, https://doi.org/10.5194/asr-16-95-2019, 2019
Short summary
Short summary
Raindrop shapes and fall velocities are presented for two high-wind/turbulent events. Results show strong gusts, directional wind shifts and/or inferred high turbulence intensity are correlated with reduced fall speeds, reaching values ~ 25–30 % less than the expected values, i.e. sub-terminal fall speeds. Significant percentage of asymmetric drops deviating from the most probable ax-isymmetric shapes was also detected during high turbulent intensities.
Anja Costa, Jessica Meyer, Armin Afchine, Anna Luebke, Gebhard Günther, James R. Dorsey, Martin W. Gallagher, Andre Ehrlich, Manfred Wendisch, Darrel Baumgardner, Heike Wex, and Martina Krämer
Atmos. Chem. Phys., 17, 12219–12238, https://doi.org/10.5194/acp-17-12219-2017, https://doi.org/10.5194/acp-17-12219-2017, 2017
Short summary
Short summary
The paper presents 38 h of in situ cloud spectrometer observations of microphysical cloud properties in the Arctic, midlatitudes and tropics. The clouds are classified via particle concentrations, size distributions, and – as a novelty – small particle aspherical fractions. Cloud-type profiles are given for different temperatures and locations. The results confine regions where different cloud transformation processes occurred and emphasise the importance of small particle shape detection.
Ulrich Schumann, Robert Baumann, Darrel Baumgardner, Sarah T. Bedka, David P. Duda, Volker Freudenthaler, Jean-Francois Gayet, Andrew J. Heymsfield, Patrick Minnis, Markus Quante, Ehrhard Raschke, Hans Schlager, Margarita Vázquez-Navarro, Christiane Voigt, and Zhien Wang
Atmos. Chem. Phys., 17, 403–438, https://doi.org/10.5194/acp-17-403-2017, https://doi.org/10.5194/acp-17-403-2017, 2017
Short summary
Short summary
The initially linear clouds often seen behind aircraft are known as contrails. Contrails are prototype cirrus clouds forming under well-known conditions, but with less certain life cycle and climate effects. This paper collects contrail data from a large set of measurements and compares them among each other and with models. The observations show consistent contrail properties over a wide range of aircraft and atmosphere conditions. The dataset is available for further research.
Ana Graciela Ulke, Marcela M. Torres Brizuela, Graciela B. Raga, and Darrel Baumgardner
Nat. Hazards Earth Syst. Sci., 16, 2159–2175, https://doi.org/10.5194/nhess-16-2159-2016, https://doi.org/10.5194/nhess-16-2159-2016, 2016
Short summary
Short summary
The eruption in June 2011 of the Puyehue-Cordón Caulle Volcanic Complex (Chile) impacted air traffic around the Southern Hemisphere for several months. The ash deposited in vast areas of the Patagonian steppe was subjected to the strong wind conditions prevalent during the austral winter and spring. An ash resuspension event impacted Buenos Aires and resulted in the closure of airports in the area on 16 October 2011. Measurements of aerosol properties clearly indicate the enhanced concentrations
Mark Hernandez, Anne E. Perring, Kevin McCabe, Greg Kok, Gary Granger, and Darrel Baumgardner
Atmos. Meas. Tech., 9, 3283–3292, https://doi.org/10.5194/amt-9-3283-2016, https://doi.org/10.5194/amt-9-3283-2016, 2016
Short summary
Short summary
We have performed laboratory experiments examining a large set of known bacterial, fungal and pollen species using a Wideband Integrated Bioaerosol Sensor (WIBS). The instrumental response is shown to be sufficiently distinct for these classes of particles to distinguish between them, and this library will provide a framework for interpretation of UV-induced fluorescence measurements of atmospheric bioaerosol. Atmospheric implications and instrumental considerations are discussed.
Anna E. Luebke, Armin Afchine, Anja Costa, Jens-Uwe Grooß, Jessica Meyer, Christian Rolf, Nicole Spelten, Linnea M. Avallone, Darrel Baumgardner, and Martina Krämer
Atmos. Chem. Phys., 16, 5793–5809, https://doi.org/10.5194/acp-16-5793-2016, https://doi.org/10.5194/acp-16-5793-2016, 2016
Short summary
Short summary
In this study, we present observational evidence to show that two distinct types of cirrus clouds exist – in situ origin and liquid origin cirrus. These two types differ by their formation mechanism and other properties. Airborne, in-cloud measurements of cloud ice water content (IWC), ice crystal concentration (Nice), and ice crystal size from the 2014 ML-CIRRUS campaign provide cloud samples that have been divided and analyzed according to their origin type.
María José Granados-Muñoz, Juan Antonio Bravo-Aranda, Darrel Baumgardner, Juan Luis Guerrero-Rascado, Daniel Pérez-Ramírez, Francisco Navas-Guzmán, Igor Veselovskii, Hassan Lyamani, Antonio Valenzuela, Francisco José Olmo, Gloria Titos, Javier Andrey, Anatoli Chaikovsky, Oleg Dubovik, Manuel Gil-Ojeda, and Lucas Alados-Arboledas
Atmos. Meas. Tech., 9, 1113–1133, https://doi.org/10.5194/amt-9-1113-2016, https://doi.org/10.5194/amt-9-1113-2016, 2016
Short summary
Short summary
A Saharan dust event is studied in detail using ground-based remote sensing measurements from lidar technology, as well as sun- and star-photometers. The use of combined techniques allows for obtaining both profiles and column-integrated microphysical properties during night and daytime. Besides, for the first time a validation of the CAS-POL depolarization measurements and LIRIC profiles is performed, thanks to the availability of aircraft in situ measurements, obtaining reasonable agreement.
Martina Krämer, Christian Rolf, Anna Luebke, Armin Afchine, Nicole Spelten, Anja Costa, Jessica Meyer, Martin Zöger, Jessica Smith, Robert L. Herman, Bernhard Buchholz, Volker Ebert, Darrel Baumgardner, Stephan Borrmann, Marcus Klingebiel, and Linnea Avallone
Atmos. Chem. Phys., 16, 3463–3483, https://doi.org/10.5194/acp-16-3463-2016, https://doi.org/10.5194/acp-16-3463-2016, 2016
Short summary
Short summary
A guide to cirrus clouds is compiled from extensive model simulations and aircraft observations. Two types of cirrus are found: rather thin in situ cirrus that form directly as ice and thicker liquid origin cirrus consisting of uplifted frozen liquid drops. Over Europe, thinner in situ and liquid origin cirrus occur often together with frontal systems, while over the US and the Tropics, thick liquid origin cirrus formed in large convective systems are detected more frequently.
A. Retama, D. Baumgardner, G. B. Raga, G. R. McMeeking, and J. W. Walker
Atmos. Chem. Phys., 15, 9693–9709, https://doi.org/10.5194/acp-15-9693-2015, https://doi.org/10.5194/acp-15-9693-2015, 2015
Short summary
Short summary
Extended measurements of equivalent black carbon (eBC) derived from light absorption measurements have been made with a PAX over a 13 month period. The daily trends in eBC and other co-pollutants are evaluated with respect to season.
The primary factors that led to large changes between the wet and dry seasons are the accelerated vertical mixing of boundary layer and free tropospheric air, by the formation of clouds and decreased actinic flux that reduces the production of ozone.
K. Beswick, D. Baumgardner, M. Gallagher, A. Volz-Thomas, P. Nedelec, K.-Y. Wang, and S. Lance
Atmos. Meas. Tech., 7, 1443–1457, https://doi.org/10.5194/amt-7-1443-2014, https://doi.org/10.5194/amt-7-1443-2014, 2014
G. B. Raga, D. Baumgardner, A. G. Ulke, M. Torres Brizuela, and B. Kucienska
Nat. Hazards Earth Syst. Sci., 13, 2319–2330, https://doi.org/10.5194/nhess-13-2319-2013, https://doi.org/10.5194/nhess-13-2319-2013, 2013
Related subject area
Subject: Others (Wind, Precipitation, Temperature, etc.) | Technique: In Situ Measurement | Topic: Data Processing and Information Retrieval
The role of time averaging of eddy covariance fluxes on water use efficiency dynamics of maize
Number- and size-controlled rainfall regimes in the Netherlands: physical reality or statistical mirage?
The Far-INfrarEd Spectrometer for Surface Emissivity (FINESSE) – Part 2: First measurements of the emissivity of water in the far-infrared
Hailstorm events in the Central Andes of Peru: insights from historical data and radar microphysics
Hybrid instrument network optimization for air quality monitoring
Objective identification of pressure wave events from networks of 1 Hz, high-precision sensors
Adjustment of 1 min rain gauge time series using co-located drop size distribution and wind speed measurements
Estimating turbulent energy flux vertical profiles from uncrewed aircraft system measurements: exemplary results for the MOSAiC campaign
Gap filling of turbulent heat fluxes over rice–wheat rotation croplands using the random forest model
Estimation of raindrop size distribution and rain rate with infrared surveillance camera in dark conditions
Estimates of the spatially complete, observational-data-driven planetary boundary layer height over the contiguous United States
Detection of turbulence occurrences from temperature, pressure, and position measurements under superpressure balloons
Inferring surface energy fluxes using drone data assimilation in large eddy simulations
Raindrop size distribution (DSD) during the passage of tropical cyclone Nivar: effect of measuring principle and wind on DSDs and retrieved rain integral and polarimetric parameters from impact and laser disdrometers
Automatic quality control of telemetric rain gauge data providing quantitative quality information (RainGaugeQC)
Testing the efficacy of atmospheric boundary layer height detection algorithms using uncrewed aircraft system data from MOSAiC
Considerations for improving data quality of thermo-hygrometer sensors on board unmanned aerial systems for planetary boundary layer research
Characteristics of the derived energy dissipation rate using the 1 Hz commercial aircraft quick access recorder (QAR) data
Low-level buoyancy as a tool to understand boundary layer transitions
Estimating vertical wind power density using tower observation and empirical models over varied desert steppe terrain in northern China
Air temperature equation derived from sonic temperature and water vapor mixing ratio for turbulent airflow sampled through closed-path eddy-covariance flux systems
Wind speed and direction estimation from wave spectra using deep learning
Options to correct local turbulent flux measurements for large-scale fluxes using an approach based on large-eddy simulation
Global ensemble of temperatures over 1850–2018: quantification of uncertainties in observations, coverage, and spatial modeling (GETQUOCS)
Reconstruction of the mass and geometry of snowfall particles from multi-angle snowflake camera (MASC) images
A new zenith hydrostatic delay model for real-time retrievals of GNSS-PWV
Sampling error in aircraft flux measurements based on a high-resolution large eddy simulation of the marine boundary layer
Separation of convective and stratiform precipitation using polarimetric radar data with a support vector machine method
An approach to minimize aircraft motion bias in multi-hole probe wind measurements made by small unmanned aerial systems
Interpolation uncertainty of atmospheric temperature profiles
Unsupervised classification of snowflake images using a generative adversarial network and K-medoids classification
An improved post-processing technique for automatic precipitation gauge time series
Retrieval of eddy dissipation rate from derived equivalent vertical gust included in Aircraft Meteorological Data Relay (AMDAR)
Atmospheric condition identification in multivariate data through a metric for total variation
Identifying persistent temperature inversion events in a subalpine basin using radon-222
Evaluation of wake influence on high-resolution balloon-sonde measurements
Improving the mean and uncertainty of ultraviolet multi-filter rotating shadowband radiometer in situ calibration factors: utilizing Gaussian process regression with a new method to estimate dynamic input uncertainty
Empirical high-resolution wind field and gust model in mountainous and hilly terrain based on the dense WegenerNet station networks
Performance of the FMI cosine error correction method for the Brewer spectral UV measurements
Computational efficiency for the surface renewal method
Novel approaches to estimating the turbulent kinetic energy dissipation rate from low- and moderate-resolution velocity fluctuation time series
Smoothing data series by means of cubic splines: quality of approximation and introduction of a repeating spline approach
Data-driven clustering of rain events: microphysics information derived from macro-scale observations
Solid hydrometeor classification and riming degree estimation from pictures collected with a Multi-Angle Snowflake Camera
Dust opacities inside the dust devil column in the Taklimakan Desert
Comparison of GPS tropospheric delays derived from two consecutive EPN reprocessing campaigns from the point of view of climate monitoring
Ensemble mean density and its connection to other microphysical properties of falling snow as observed in Southern Finland
An automated nowcasting model of significant instability events in the flight terminal area of Rio de Janeiro, Brazil
Retrieving atmospheric turbulence information from regular commercial aircraft using Mode-S and ADS-B
An automatic precipitation-phase distinction algorithm for optical disdrometer data over the global ocean
Arun Rao Karimindla, Shweta Kumari, Saipriya S R, Syam Chintala, and BVN P. Kambhammettu
Atmos. Meas. Tech., 17, 5477–5490, https://doi.org/10.5194/amt-17-5477-2024, https://doi.org/10.5194/amt-17-5477-2024, 2024
Short summary
Short summary
This study investigates the role of the averaging period of eddy covariance fluxes on the energy balance ratio and further propagation into water use efficiency dynamics. Application was demonstrated on a maize field considering EC flux data. We found that the time averages of EC fluxes that yield the most effective EBR are at 45 and 60 min. The 30 min averaging period was insufficient to capture low-frequency fluxes. Time averaging of EC fluxes needs to be performed based on crop growth stage.
Marc Schleiss
Atmos. Meas. Tech., 17, 4789–4802, https://doi.org/10.5194/amt-17-4789-2024, https://doi.org/10.5194/amt-17-4789-2024, 2024
Short summary
Short summary
Research is conducted to identify special rainfall patterns in the Netherlands using multiple types of rainfall sensors. A total of eight potentially unique events are analyzed, considering both the number and size of raindrops. However, no clear evidence supporting the existence of a special rainfall regime could be found. The results highlight the challenges in experimentally confirming well-established theoretical ideas in the field of precipitation sciences.
Laura Warwick, Jonathan E. Murray, and Helen Brindley
Atmos. Meas. Tech., 17, 4777–4787, https://doi.org/10.5194/amt-17-4777-2024, https://doi.org/10.5194/amt-17-4777-2024, 2024
Short summary
Short summary
We describe a method for measuring the emissivity of natural surfaces using data from the new Far-INfrarEd Spectrometer for Surface Emissivity (FINESSE) instrument. We demonstrate our method by making measurements of the emissivity of water. We then compare our results to the emissivity predicted using a model and find good agreement. The observations from FINESSE are novel because they allow us to determine surface emissivity at longer wavelengths than have been routinely measured before.
Jairo M. Valdivia, José Luis Flores-Rojas, Josep J. Prado, David Guizado, Elver Villalobos-Puma, Stephany Callañaupa, and Yamina Silva-Vidal
Atmos. Meas. Tech., 17, 2295–2316, https://doi.org/10.5194/amt-17-2295-2024, https://doi.org/10.5194/amt-17-2295-2024, 2024
Short summary
Short summary
In this study, we explored hailstorms in the Central Andes of Peru. We used historical records and radar measurements to understand the frequency, timing, and characteristics of these hail events. Our research found a trend of decreasing hail frequency, probably due to anthropogenic climate change. Understanding these weather patterns is critical for local communities, as it can help improve weather forecasts and manage risks related to these potentially destructive events.
Nishant Ajnoti, Hemant Gehlot, and Sachchida Nand Tripathi
Atmos. Meas. Tech., 17, 1651–1664, https://doi.org/10.5194/amt-17-1651-2024, https://doi.org/10.5194/amt-17-1651-2024, 2024
Short summary
Short summary
This research focuses on the optimal placement of hybrid instruments (sensors and monitors) to maximize satisfaction function considering population, PM2.5 concentration, budget, and other factors. Two algorithms are developed in this study: a genetic algorithm and a greedy algorithm. We tested these algorithms on various regions. The insights of this work aid in quantitative placement of air quality monitoring instruments in large cities, moving away from ad hoc approaches.
Luke R. Allen, Sandra E. Yuter, Matthew A. Miller, and Laura M. Tomkins
Atmos. Meas. Tech., 17, 113–134, https://doi.org/10.5194/amt-17-113-2024, https://doi.org/10.5194/amt-17-113-2024, 2024
Short summary
Short summary
We present a data set of high-precision surface air pressure observations and a method for detecting wave signals from the time series of pressure. A wavelet-based method is used to find wave signals at specific times and wave periods. From networks of pressure sensors spaced tens of kilometers apart, the wave phase speed and direction are estimated. Examples of wave events and their meteorological context are shown using radar data, weather balloon data, and other surface weather observations.
Arianna Cauteruccio, Mattia Stagnaro, Luca G. Lanza, and Pak-Wai Chan
Atmos. Meas. Tech., 16, 4155–4163, https://doi.org/10.5194/amt-16-4155-2023, https://doi.org/10.5194/amt-16-4155-2023, 2023
Short summary
Short summary
Adjustments for the wind-induced bias of traditional rainfall gauges are applied to data from the Hong Kong Observatory using numerical simulation results. An optical disdrometer allows us to infer the collection efficiency of the rainfall gauge. Due to the local climatology, adjustments are limited but result in a significant amount of available freshwater resources that would be missing from the calculated hydrological budget of the region should the adjustments be neglected.
Ulrike Egerer, John J. Cassano, Matthew D. Shupe, Gijs de Boer, Dale Lawrence, Abhiram Doddi, Holger Siebert, Gina Jozef, Radiance Calmer, Jonathan Hamilton, Christian Pilz, and Michael Lonardi
Atmos. Meas. Tech., 16, 2297–2317, https://doi.org/10.5194/amt-16-2297-2023, https://doi.org/10.5194/amt-16-2297-2023, 2023
Short summary
Short summary
This paper describes how measurements from a small uncrewed aircraft system can be used to estimate the vertical turbulent heat energy exchange between different layers in the atmosphere. This is particularly important for the atmosphere in the Arctic, as turbulent exchange in this region is often suppressed but is still important to understand how the atmosphere interacts with sea ice. We present three case studies from the MOSAiC field campaign in Arctic sea ice in 2020.
Jianbin Zhang, Zexia Duan, Shaohui Zhou, Yubin Li, and Zhiqiu Gao
Atmos. Meas. Tech., 16, 2197–2207, https://doi.org/10.5194/amt-16-2197-2023, https://doi.org/10.5194/amt-16-2197-2023, 2023
Short summary
Short summary
In this paper, we used a random forest model to fill the observation gaps of the fluxes measured during 2015–2019. We found that the net radiation was the most important input variable. And we justified the reliability of the model. Further, it was revealed that the model performed better after relative humidity was removed from the input. Lastly, we compared the results of the model with those of three other machine learning models, and we found that the model outperformed all of them.
Jinwook Lee, Jongyun Byun, Jongjin Baik, Changhyun Jun, and Hyeon-Joon Kim
Atmos. Meas. Tech., 16, 707–725, https://doi.org/10.5194/amt-16-707-2023, https://doi.org/10.5194/amt-16-707-2023, 2023
Short summary
Short summary
Our study addresses raindrop size distribution and rain rate by extracting rain streaks using a k-nearest-neighbor-based algorithm, estimating rainfall intensity using raindrop size distribution based on physical optics analysis, and verifying the estimated raindrop size distribution using a disdrometer. Experimentation demonstrated the possibility of estimating an image-based raindrop size distribution and rain rate obtained based on such low-cost equipment in dark conditions.
Zolal Ayazpour, Shiqi Tao, Dan Li, Amy Jo Scarino, Ralph E. Kuehn, and Kang Sun
Atmos. Meas. Tech., 16, 563–580, https://doi.org/10.5194/amt-16-563-2023, https://doi.org/10.5194/amt-16-563-2023, 2023
Short summary
Short summary
Accurate knowledge of the planetary boundary layer height (PBLH) is essential to study air pollution. However, PBLH observations are sparse in space and time, and PBLHs used in atmospheric models are often inaccurate. Using PBLH observations from the Aircraft Meteorological DAta Relay (AMDAR), we present a machine learning framework to produce a spatially complete PBLH product over the contiguous US that shows a better agreement with reference PBLH observations than commonly used PBLH products.
Richard Wilson, Clara Pitois, Aurélien Podglajen, Albert Hertzog, Milena Corcos, and Riwal Plougonven
Atmos. Meas. Tech., 16, 311–330, https://doi.org/10.5194/amt-16-311-2023, https://doi.org/10.5194/amt-16-311-2023, 2023
Short summary
Short summary
Strateole-2 is an French–US initiative designed to study atmospheric events in the tropical upper troposphere–lower stratosphere. In this work, data from several superpressure balloons, capable of staying aloft at an altitude of 18–20 km for over 3 months, were used. The present article describes methods to detect the occurrence of atmospheric turbulence – one efficient process impacting the properties of the atmosphere composition via stirring and mixing.
Norbert Pirk, Kristoffer Aalstad, Sebastian Westermann, Astrid Vatne, Alouette van Hove, Lena Merete Tallaksen, Massimo Cassiani, and Gabriel Katul
Atmos. Meas. Tech., 15, 7293–7314, https://doi.org/10.5194/amt-15-7293-2022, https://doi.org/10.5194/amt-15-7293-2022, 2022
Short summary
Short summary
In this study, we show how sparse and noisy drone measurements can be combined with an ensemble of turbulence-resolving wind simulations to estimate uncertainty-aware surface energy exchange. We demonstrate the feasibility of this drone data assimilation framework in a series of synthetic and real-world experiments. This new framework can, in future, be applied to estimate energy and gas exchange in heterogeneous landscapes more representatively than conventional methods.
Basivi Radhakrishna
Atmos. Meas. Tech., 15, 6705–6722, https://doi.org/10.5194/amt-15-6705-2022, https://doi.org/10.5194/amt-15-6705-2022, 2022
Short summary
Short summary
Raindrop size distributions (DSDs) measured by various types of disdrometers are different in the same environmental conditions. The mass-weighted mean diameter (Dm) measured from JWD is larger, and ZDR is smaller than LPM and PARSIVEL due to the resonance effect at X-band frequency. The effect of wind on DSD measured by various disdrometers is not uniform in different regions of a tropical cyclone.
Katarzyna Ośródka, Irena Otop, and Jan Szturc
Atmos. Meas. Tech., 15, 5581–5597, https://doi.org/10.5194/amt-15-5581-2022, https://doi.org/10.5194/amt-15-5581-2022, 2022
Short summary
Short summary
The quality control of sub-hourly rain gauge data is a challenging task due to the high variability and low spatial consistency of the data. We developed an innovative approach to the quality control of telemetric rain gauge data focused on assessing the reliability of individual observations. Our scheme employs weather radar data to detect erroneous rain gauge measurements and to assess the data reliability. The scheme is used operationally by the Polish meteorological and hydrological service.
Gina Jozef, John Cassano, Sandro Dahlke, and Gijs de Boer
Atmos. Meas. Tech., 15, 4001–4022, https://doi.org/10.5194/amt-15-4001-2022, https://doi.org/10.5194/amt-15-4001-2022, 2022
Short summary
Short summary
During the MOSAiC expedition, meteorological conditions over the lowest 1 km of the atmosphere were sampled with the DataHawk2 uncrewed aircraft system. These data were used to identify the best method for atmospheric boundary layer height detection by comparing visually identified subjective boundary layer height to that identified by several objective automated detection methods. The results show a bulk Richardson number-based approach gives the best estimate of boundary layer height.
Antonio R. Segales, Phillip B. Chilson, and Jorge L. Salazar-Cerreño
Atmos. Meas. Tech., 15, 2607–2621, https://doi.org/10.5194/amt-15-2607-2022, https://doi.org/10.5194/amt-15-2607-2022, 2022
Short summary
Short summary
The mitigation of undesired contamination, sensor characterization, and signal conditioning and restoration is crucial to improve the reliability of the weather unmanned aerial system (UAS) deliverables. This study presents an overview of the general considerations and procedures to compensate for slow sensor response and other sources of error for temperature and humidity measurements collected using a UAS.
Soo-Hyun Kim, Jeonghoe Kim, Jung-Hoon Kim, and Hye-Yeong Chun
Atmos. Meas. Tech., 15, 2277–2298, https://doi.org/10.5194/amt-15-2277-2022, https://doi.org/10.5194/amt-15-2277-2022, 2022
Short summary
Short summary
The cube root of the energy dissipation rate (EDR), as a standard reporting metric of atmospheric turbulence, is estimated using 1 Hz commercial quick access recorder data from Korean-based national air carriers with two different types of aircraft. Various EDRs are estimated using zonal, meridional, and derived vertical wind components and the derived equivalent vertical gust. Characteristics of the observed EDR estimates using 1 Hz flight data are examined to observe strong turbulence cases.
Francesca M. Lappin, Tyler M. Bell, Elizabeth A. Pillar-Little, and Phillip B. Chilson
Atmos. Meas. Tech., 15, 1185–1200, https://doi.org/10.5194/amt-15-1185-2022, https://doi.org/10.5194/amt-15-1185-2022, 2022
Short summary
Short summary
This study evaluates how a classically defined variable, air parcel buoyancy, can be used to interpret transitions in the atmospheric boundary layer (ABL). To capture the high-resolution variations, remotely piloted aircraft systems are used to collect data in two field campaigns. This paper finds that buoyancy has distinct evolutions prior to low-level jet and convective initiation cases. Additionally, buoyancy mixes well to act as an ABL height indicator comparable to other methods.
Shaohui Zhou, Yuanjian Yang, Zhiqiu Gao, Xingya Xi, Zexia Duan, and Yubin Li
Atmos. Meas. Tech., 15, 757–773, https://doi.org/10.5194/amt-15-757-2022, https://doi.org/10.5194/amt-15-757-2022, 2022
Short summary
Short summary
Our research has determined the possible relationship between Weibull natural wind mesoscale parameter c and shape factor k with height under the conditions of a desert steppe terrain in northern China, which has great potential in wind power generation. We have gained an enhanced understanding of the seasonal changes in the surface roughness of the desert grassland and the changes in the incoming wind direction.
Xinhua Zhou, Tian Gao, Eugene S. Takle, Xiaojie Zhen, Andrew E. Suyker, Tala Awada, Jane Okalebo, and Jiaojun Zhu
Atmos. Meas. Tech., 15, 95–115, https://doi.org/10.5194/amt-15-95-2022, https://doi.org/10.5194/amt-15-95-2022, 2022
Short summary
Short summary
Air temperature from sonic temperature and air moisture has been used without an exact equation. We present an exact equation of such air temperature for closed-path eddy-covariance flux measurements. Air temperature from this equation is equivalent to sonic temperature in its accuracy and frequency response. It is a choice for advanced flux topics because, with it, thermodynamic variables in the flux measurements can be temporally synchronized and spatially matched at measurement scales.
Haoyu Jiang
Atmos. Meas. Tech., 15, 1–9, https://doi.org/10.5194/amt-15-1-2022, https://doi.org/10.5194/amt-15-1-2022, 2022
Short summary
Short summary
Sea surface wind and waves are important ocean parameters that can be continuously observed by meteorological buoys. Meteorological buoys are sparse in the ocean due to their high cost of deployment and maintenance. In contrast, low-cost compact wave buoys are suited for deployment in large numbers. Although wave buoys are not designed for wind measurement, we found that deep learning can estimate wind from wave measurements accurately, making wave buoys a good-quality data source for sea wind.
Matthias Mauder, Andreas Ibrom, Luise Wanner, Frederik De Roo, Peter Brugger, Ralf Kiese, and Kim Pilegaard
Atmos. Meas. Tech., 14, 7835–7850, https://doi.org/10.5194/amt-14-7835-2021, https://doi.org/10.5194/amt-14-7835-2021, 2021
Short summary
Short summary
Turbulent flux measurements suffer from a general systematic underestimation. One reason for this bias is non-local transport by large-scale circulations. A recently developed model for this additional transport of sensible and latent energy is evaluated for three different test sites. Different options on how to apply this correction are presented, and the results are evaluated against independent measurements.
Maryam Ilyas, Douglas Nychka, Chris Brierley, and Serge Guillas
Atmos. Meas. Tech., 14, 7103–7121, https://doi.org/10.5194/amt-14-7103-2021, https://doi.org/10.5194/amt-14-7103-2021, 2021
Short summary
Short summary
Instrumental temperature records are fundamental to climate science. There are spatial gaps in the distribution of these measurements across the globe. This lack of spatial coverage introduces coverage error. In this research, a methodology is developed and used to quantify the coverage errors. It results in a data product that, for the first time, provides a full description of both the spatial coverage uncertainties along with the uncertainties in the modeling of these spatial gaps.
Jussi Leinonen, Jacopo Grazioli, and Alexis Berne
Atmos. Meas. Tech., 14, 6851–6866, https://doi.org/10.5194/amt-14-6851-2021, https://doi.org/10.5194/amt-14-6851-2021, 2021
Short summary
Short summary
Measuring the shape, size and mass of a large number of snowflakes is a challenging task; it is hard to achieve in an automatic and instrumented manner. We present a method to retrieve these properties of individual snowflakes using as input a triplet of images/pictures automatically collected by a multi-angle snowflake camera (MASC) instrument. Our method, based on machine learning, is trained on artificially generated snowflakes and evaluated on 3D-printed snowflake replicas.
Longjiang Li, Suqin Wu, Kefei Zhang, Xiaoming Wang, Wang Li, Zhen Shen, Dantong Zhu, Qimin He, and Moufeng Wan
Atmos. Meas. Tech., 14, 6379–6394, https://doi.org/10.5194/amt-14-6379-2021, https://doi.org/10.5194/amt-14-6379-2021, 2021
Short summary
Short summary
The zenith hydrostatic delay (ZHD) derived from blind models are of low accuracy, especially in mid- and high-latitude regions. To address this issue, the ratio of the ZHD to zenith total delay (ZTD) is firstly investigated; then, based on the relationship between the ZHD and ZTD, a new ZHD model was developed using the back propagation artificial neural network (BP-ANN) method which took the ZTD as an input variable. The model outperforms blind models.
Grant W. Petty
Atmos. Meas. Tech., 14, 1959–1976, https://doi.org/10.5194/amt-14-1959-2021, https://doi.org/10.5194/amt-14-1959-2021, 2021
Short summary
Short summary
Aircraft measurements of turbulent fluxes of matter and energy are important in field investigations of the interaction of the Earth's surface and the atmosphere. Because these measurements are of randomly fluctuating quantities, averages must be taken over longer flight tracks to reduce uncertainty. This paper investigates the relationship between track length and measurement error using a computer model simulation of a marine environment and compares the results with published theory.
Yadong Wang, Lin Tang, Pao-Liang Chang, and Yu-Shuang Tang
Atmos. Meas. Tech., 14, 185–197, https://doi.org/10.5194/amt-14-185-2021, https://doi.org/10.5194/amt-14-185-2021, 2021
Short summary
Short summary
The motivation of this work is to develop a precipitation separation approach that can be implemented on those radars with fast scanning schemes. In these schemes, the higher tilt radar data are not available, which poses a challenge for the traditional approaches. This approach uses artificial intelligence, which integrates polarimetric radar variables. The quantitative precipitation estimation will benefit from the output of this algorithm.
Loiy Al-Ghussain and Sean C. C. Bailey
Atmos. Meas. Tech., 14, 173–184, https://doi.org/10.5194/amt-14-173-2021, https://doi.org/10.5194/amt-14-173-2021, 2021
Short summary
Short summary
Unmanned aerial vehicles equipped with multi-hole probes are an effective approach to measure the wind vector with high spatial and temporal resolution. However, the aircraft motion must be removed from the measured signal first, a process often introducing bias due to small errors in the relative orientation of coordinates. We present an approach that has successfully been applied in post-processing, which was found to minimize the influence of aircraft motion on wind measurements.
Alessandro Fassò, Michael Sommer, and Christoph von Rohden
Atmos. Meas. Tech., 13, 6445–6458, https://doi.org/10.5194/amt-13-6445-2020, https://doi.org/10.5194/amt-13-6445-2020, 2020
Short summary
Short summary
Modern radiosonde balloons fly from ground level up to the lower stratosphere and take temperature measurements. What is the uncertainty of interpolated values in the resulting atmospheric temperature profiles? To answer this question, we introduce a general statistical–mathematical model for the computation of interpolation uncertainty. Analysing more than 51 million measurements, we provide some understanding of the consequences of filling missing data with interpolated ones.
Jussi Leinonen and Alexis Berne
Atmos. Meas. Tech., 13, 2949–2964, https://doi.org/10.5194/amt-13-2949-2020, https://doi.org/10.5194/amt-13-2949-2020, 2020
Short summary
Short summary
The appearance of snowflakes provides a signature of the atmospheric processes that created them. To get this information from large numbers of snowflake images, automated analysis using computer image recognition is needed. In this work, we use a neural network that learns the structure of the snowflake images to divide a snowflake dataset into classes corresponding to different sizes and structures. Unlike with most comparable methods, only minimal input from a human expert is needed.
Amber Ross, Craig D. Smith, and Alan Barr
Atmos. Meas. Tech., 13, 2979–2994, https://doi.org/10.5194/amt-13-2979-2020, https://doi.org/10.5194/amt-13-2979-2020, 2020
Short summary
Short summary
The raw data derived from most automated accumulating precipitation gauges often suffer from non-precipitation-related fluctuations in the measurement of the gauge bucket weights from which the precipitation amount is determined. This noise can be caused by electrical interference, mechanical noise, and evaporation. This paper presents an automated filtering technique that builds on the principle of iteratively balancing noise to produce a clean precipitation time series.
Soo-Hyun Kim, Hye-Yeong Chun, Jung-Hoon Kim, Robert D. Sharman, and Matt Strahan
Atmos. Meas. Tech., 13, 1373–1385, https://doi.org/10.5194/amt-13-1373-2020, https://doi.org/10.5194/amt-13-1373-2020, 2020
Short summary
Short summary
We retrieve the eddy dissipation rate (EDR) from the derived equivalent vertical gust included in the Aircraft Meteorological Data Relay data for more reliable and consistent observations of aviation turbulence globally with the single preferred EDR metric. We convert the DEVG to the EDR using two methods (lognormal mapping scheme and best-fit curve between EDR and DEVG), and the DEVG-derived EDRs are evaluated against in situ EDR data reported by US-operated carriers.
Nicholas Hamilton
Atmos. Meas. Tech., 13, 1019–1032, https://doi.org/10.5194/amt-13-1019-2020, https://doi.org/10.5194/amt-13-1019-2020, 2020
Short summary
Short summary
The identification of atmospheric conditions within a multivariable atmospheric data set is an important step in validating emerging and existing models used to simulate wind plant flows and operational strategies. The total variation approach developed here offers a method founded in tested mathematical metrics and can be used to identify and characterize periods corresponding to quiescent conditions or specific events of interest for study or wind energy development.
Dafina Kikaj, Janja Vaupotič, and Scott D. Chambers
Atmos. Meas. Tech., 12, 4455–4477, https://doi.org/10.5194/amt-12-4455-2019, https://doi.org/10.5194/amt-12-4455-2019, 2019
Short summary
Short summary
A new method was developed to identify persistent temperature inversion events in a subalpine basin using a radon-based method (RBM). By comparing with an existing pseudo-vertical temperature gradient method, the RBM was shown to be more reliable and seasonally independent. The RBM has the potential to increase the understanding of meteorological controls on air pollution episodes in complex terrain beyond the capability of contemporary atmospheric stability classification tools.
Jens Faber, Michael Gerding, Andreas Schneider, Andreas Dörnbrack, Henrike Wilms, Johannes Wagner, and Franz-Josef Lübken
Atmos. Meas. Tech., 12, 4191–4210, https://doi.org/10.5194/amt-12-4191-2019, https://doi.org/10.5194/amt-12-4191-2019, 2019
Short summary
Short summary
Atmospheric measurements on rising balloons can be compromised by the balloon's wake. The aim of this study is to provide a tool for assessing the likelihood of encountering the balloon's wake at the position of the gondola. This includes an uncertainty analysis of the calculation and a retrieval of vertical winds. We find an average wake encounter probability of 28 % for a standard radiosonde. Additionally, we evaluate the influence of wake from smaller objects on turbulence measurements.
Maosi Chen, Zhibin Sun, John M. Davis, Yan-An Liu, Chelsea A. Corr, and Wei Gao
Atmos. Meas. Tech., 12, 935–953, https://doi.org/10.5194/amt-12-935-2019, https://doi.org/10.5194/amt-12-935-2019, 2019
Short summary
Short summary
Combining a new dynamic uncertainty estimation method with Gaussian process regression (GP), we provide a generic and robust solution to estimate the underlying mean and uncertainty functions of time series with variable mean, noise, sampling density, and length of gaps. The GP solution was applied and validated on three UV-MFRSR Vo time series at three ground sites with improved accuracy of the smoothed time series in terms of aerosol optical depth compared with two other smoothing methods.
Christoph Schlager, Gottfried Kirchengast, and Juergen Fuchsberger
Atmos. Meas. Tech., 11, 5607–5627, https://doi.org/10.5194/amt-11-5607-2018, https://doi.org/10.5194/amt-11-5607-2018, 2018
Short summary
Short summary
In this work we further developed and evaluated an operational weather diagnostic application, the WegenerNet Wind Product Generator (WPG), and applied it to the WegenerNet Johnsbachtal (JBT), a dense meteorological station network located in a mountainous Alpine region. The WPG automatically generates gridded high-resolution wind fields in near-real time with a temporal resolution of 30 min and a spatial resolution of 100 m x 100 m.
Kaisa Lakkala, Antti Arola, Julian Gröbner, Sergio Fabian León-Luis, Alberto Redondas, Stelios Kazadzis, Tomi Karppinen, Juha Matti Karhu, Luca Egli, Anu Heikkilä, Tapani Koskela, Antonio Serrano, and José Manuel Vilaplana
Atmos. Meas. Tech., 11, 5167–5180, https://doi.org/10.5194/amt-11-5167-2018, https://doi.org/10.5194/amt-11-5167-2018, 2018
Short summary
Short summary
The performance of the cosine error correction method for correcting spectral UV measurements of the Brewer spectroradiometer was studied. The correction depends on the sky radiation distribution, which can change during one spectral scan. The results showed that the correction varied between 4 and 14 %, and that the relative differences between the reference and the Brewer diminished by 10 %. The method is applicable to other instruments as long as the required input parameters are available.
Jason Kelley and Chad Higgins
Atmos. Meas. Tech., 11, 2151–2158, https://doi.org/10.5194/amt-11-2151-2018, https://doi.org/10.5194/amt-11-2151-2018, 2018
Short summary
Short summary
Measuring fluxes of energy and trace gases using the surface renewal (SR) method can be economical and robust, but it requires computationally intensive calculations. Several new algorithms were written to perform the required calculations more efficiently and rapidly, and were tested with field data and computationally rigorous SR methods. These efficient algorithms facilitate expanded use of SR in atmospheric experiments, for applied monitoring, and in novel field implementations.
Marta Wacławczyk, Yong-Feng Ma, Jacek M. Kopeć, and Szymon P. Malinowski
Atmos. Meas. Tech., 10, 4573–4585, https://doi.org/10.5194/amt-10-4573-2017, https://doi.org/10.5194/amt-10-4573-2017, 2017
Short summary
Short summary
We propose two novel methods to estimate turbulent kinetic energy dissipation rate applicable to airborne measurements. In this way we increase robustness of the dissipation rate retrieval and extend its applicability to a wider range of data sets. The new approaches relate the predicted form of the dissipation spectrum to the mean of zero crossings of the measured velocity fluctuations. The methods are easy to implement numerically, and estimates remain unaffected by certain measurement errors.
Sabine Wüst, Verena Wendt, Ricarda Linz, and Michael Bittner
Atmos. Meas. Tech., 10, 3453–3462, https://doi.org/10.5194/amt-10-3453-2017, https://doi.org/10.5194/amt-10-3453-2017, 2017
Short summary
Short summary
Cubic splines with equidistant spline sampling points are a common method in atmospheric science for the approximation of background conditions by means of filtering superimposed fluctuations from a data series. However, splines can generate considerable artificial oscillations in the background and the residuals. We introduce a repeating spline approach which is able to significantly reduce this phenomenon and to apply it to TIMED-SABER vertical temperature profiles from 2010 to 2014.
Mohamed Djallel Dilmi, Cécile Mallet, Laurent Barthes, and Aymeric Chazottes
Atmos. Meas. Tech., 10, 1557–1574, https://doi.org/10.5194/amt-10-1557-2017, https://doi.org/10.5194/amt-10-1557-2017, 2017
Short summary
Short summary
The concept of a rain event is used to obtain a parsimonious characterisation of rain events using a minimal subset of variables at macrophysical scale. A classification in five classes is obtained in a unsupervised way from this subset. Relationships between these classes of microphysical parameters of precipitation are highlighted. There are several implications especially for remote sensing in the context of weather radar applications and quantitative precipitation estimation.
Christophe Praz, Yves-Alain Roulet, and Alexis Berne
Atmos. Meas. Tech., 10, 1335–1357, https://doi.org/10.5194/amt-10-1335-2017, https://doi.org/10.5194/amt-10-1335-2017, 2017
Short summary
Short summary
The Multi-Angle Snowflake Camera (MASC) provides high-resolution pictures of individual falling snowflakes and ice crystals. A method is proposed to automatically classify these pictures into six classes of snowflakes as well to estimate the degree of riming and to detect whether or not the particles are melting. Multinomial logistic regression is used with a manually classified
reference set. The evaluation demonstrates the good and reliable performance of the proposed technique.
Zhaopeng Luan, Yongxiang Han, Tianliang Zhao, Feng Liu, Chong Liu, Mark J. Rood, Xinghua Yang, Qing He, and Huichao Lu
Atmos. Meas. Tech., 10, 273–279, https://doi.org/10.5194/amt-10-273-2017, https://doi.org/10.5194/amt-10-273-2017, 2017
Zofia Baldysz, Grzegorz Nykiel, Andrzej Araszkiewicz, Mariusz Figurski, and Karolina Szafranek
Atmos. Meas. Tech., 9, 4861–4877, https://doi.org/10.5194/amt-9-4861-2016, https://doi.org/10.5194/amt-9-4861-2016, 2016
Short summary
Short summary
In this paper two official processing strategies of GPS observations were analysed. The main purpose was to assess differences in long-term (linear trends) and short-term (oscillations) changes between these two sets of data. Investigation was based on 18-year and 16-year time series and showed that, despite the general consistency, for selected stations a change of processing strategy may have caused significant differences (compared to the uncertainties) in estimated linear trend values.
Jussi Tiira, Dmitri N. Moisseev, Annakaisa von Lerber, Davide Ori, Ali Tokay, Larry F. Bliven, and Walter Petersen
Atmos. Meas. Tech., 9, 4825–4841, https://doi.org/10.5194/amt-9-4825-2016, https://doi.org/10.5194/amt-9-4825-2016, 2016
Short summary
Short summary
In this study winter measurements collected in Southern Finland are used to document microphysical properties of falling snow. It is shown that a new video imager can be used for such studies. Snow properties do vary between winters.
Gutemberg Borges França, Manoel Valdonel de Almeida, and Alessana C. Rosette
Atmos. Meas. Tech., 9, 2335–2344, https://doi.org/10.5194/amt-9-2335-2016, https://doi.org/10.5194/amt-9-2335-2016, 2016
Short summary
Short summary
This paper presents a novel model, based on neural network techniques, to produce short-term and locally specific forecasts of significant instability for flights in the terminal area of Rio de Janeiro's airport, Brazil. Twelve years of data were used for neural network training/validation and test. The test showed that the proposed model can grab the physical content inside the data set, and its performance is encouraging for the first and second hours to nowcast significant instability events.
Jacek M. Kopeć, Kamil Kwiatkowski, Siebren de Haan, and Szymon P. Malinowski
Atmos. Meas. Tech., 9, 2253–2265, https://doi.org/10.5194/amt-9-2253-2016, https://doi.org/10.5194/amt-9-2253-2016, 2016
Short summary
Short summary
This paper is presenting a feasibility study focused on methods of estimating the turbulence intensity based on a class of navigational messages routinely broadcast by the commercial aircraft (known as ADS-B and Mode-S). Using this kind of information could have potentially significant impact on aviation safety. Three methods have been investigated.
Jörg Burdanowitz, Christian Klepp, and Stephan Bakan
Atmos. Meas. Tech., 9, 1637–1652, https://doi.org/10.5194/amt-9-1637-2016, https://doi.org/10.5194/amt-9-1637-2016, 2016
Short summary
Short summary
We develop a new automatic algorithm to distinguish oceanic precipitation into rain, snow and mixed phase using optical disdrometers deployed on board research vessels. In combination, air temperature, relative humidity and the maximum precipitation particle diameter outperform human observer data and yield highest skill to predict the precipitation phase. This knowledge allows deriving accurate rain and snowfall rates with dense global ocean sampling, which enables satellite sensor validation.
Cited articles
Atlas, D., Srivastava, R. C., and Sekhon, R. S.:. Doppler radar
characteristics of precipitation at vertical incidence, Rev. Geophys., 11,
1–35, https://doi.org/10.1029/RG011i001p00001, 1973.
Barthazy, E., Göke, S., Schefold, R., and Högl, D.: An optical array
instrument for shape and fall velocity measurements of hydrometeors,
J. Atmos. Ocean. Tech., 21, 1400–1416,
https://doi.org/10.1175/1520-0426(2004)021<1400:AOAIFS>2.0.CO;2,
2004.
Baumgardner, D., Abel, S., Axisa, D., Cotton, R., Crosier, J., Field, P.,
Gurganus, C., Heymsfield, A., Korolev, A., Krämer, M., Lawson, P.,
McFarquhar, G., Ulanowski, J. Z., and Shik Um, J.: Chapter 9: Cloud Ice
Properties – In Situ Measurement Challenges, in: AMS Monograph on Ice
Formation and Evolution in Clouds and Precipitation: Measurement and Modeling
Challenges, edited by: Baumgardner, D., McFarquhar, G., and Heymsfield, A.,
American Meteorological Society, Boston, MA, 2016.
Beard, K. V.: Terminal velocity and shape of cloud and precipitation drops
aloft, J. Atmos. Sci., 33, 851–864,
https://doi.org/10.1175/1520-0469(1976)033<0851:TVASOC>2.0.CO;2,
1976.
Beard, K. V. and Pruppacher, H. R.: A determination of the terminal velocity
and drag of small water drops by means of a wind tunnel, J. Atmos. Sci., 26,
1066–1072,
https://doi.org/10.1175/1520-0469(1969)026<1066:ADOTTV>2.0.CO;2,
1969.
Belda, M., Holtanová, E., Halenka, T., and Kalvová, J.: Climate
classification revisited: from Köppen to Trewartha, Clim. Res., 59,
1–13, https://doi.org/10.3354/cr01204, 2014.
Bernauer, F., Hürkamp, K., Rühm, W., and Tschiersch, J.: On the
consistency of 2-D video disdrometers in measuring microphysical parameters
of solid precipitation, Atmos. Meas. Tech., 8, 3251–3261,
https://doi.org/10.5194/amt-8-3251-2015, 2015.
Foote, G. B. and Du Toit, P. S.: Terminal velocity of raindrops aloft,
J. Appl. Meteorol., 8, 249–253,
https://doi.org/10.1175/1520-0450(1969)008<0249:TVORA>2.0.CO;2,
1969.
Garrett, T. J. and Yuter, S. E.: Observed influence of riming, temperature,
and turbulence on the fallspeed of solid precipitation, Geophys. Res. Lett.,
41, 6515–6522, https://doi.org/10.1002/2014GL061016, 2014.
Garrett, T. J., Fallgatter, C., Shkurko, K., and Howlett, D.: Fall speed
measurement and high-resolution multi-angle photography of hydrometeors in
free fall, Atmos. Meas. Tech., 5, 2625–2633, https://doi.org/10.5194/amt-5-2625-2012,
2012.
Gunn, R. and Kinzer, G. D.: The terminal velocity of fall for water droplets
in stagnant air, J. Meteorol., 6, 243–248,
https://doi.org/10.1175/1520-0469(1949)006<0243:TTVOFF>2.0.CO;2,
1949.
Huang, G., Bringi, V. N., and Thurai, M.: Orientation angle distributions of
drops after an 80 m fall using a 2-D video disdrometer, J. Atmos.
Ocean. Tech., 25, 1717–1723, https://doi.org/10.1175/2008JTECHA1075.1, 2008.
Huang, G., Bringi, V. N., Cifelli, R., Hudak, D., and Petersen, W. A.:
A methodology to derive radar reflectivity–liquid equivalent snow rate
relations using c-band radar and a 2-D video disdrometer, J. Atmos. Ocean.
Tech., 27, 637–651, https://doi.org/10.1175/2009JTECHA1284.1, 2010.
Knollenberg, R.: The optical array: an alternative to scattering or
extinction for airborne particle size determination, J. Appl. Meteorol., 9,
86–103,
https://doi.org/10.1175/1520-0450(1970)009<0086:TOAAAT>2.0.CO;2,
1970.
Knollenberg, R.: Three new instruments for cloud physics measurements: the
2–D spectrometer probe, the forward scattering spectrometer probe and the
active scattering aerosol spectrometer, in: International Conference on Cloud
Physics, 26–30 July 1976, Boulder, CO, USA, American Meteorological Society,
554–561, 1976.
Knollenberg, R.: Techniques for probing cloud microstructure, in: Clouds,
Their Formation, Optical Properties and Effects, edited by: Hobbs, P. V. and
Deepak, A., Academic Press, New York, USA, 495 pp., 1981.
Korolev, A. V.: Reconstruction of the sizes of spherical particles from their
shadow images. Part I: Theoretical considerations, J. Atmos. Ocean. Tech.,
24, 376–389, https://doi.org/10.1175/JTECH1980.1, 2007.
Korolev, A. V., Kuznetsov, S. V., Makarov, Y. E., and Novikov, V. S.:
Evaluation of measurements of particle size and sample area from optical
array probes, J. Atmos. Ocean. Tech., 8, 514–522,
https://doi.org/10.1175/1520-0426(1991)008<0514:EOMOPS>2.0.CO;2,
1991.
Korolev, A. V., Strapp, J. W., and Isaac, G. A.: Evaluation of the accuracy
of PMS optical array probes, J. Atmos. Ocean. Tech., 15, 708–720,
https://doi.org/10.1175/1520-0426(1998)015<0708:EOTAOP>2.0.CO;2,
1998.
Larsen, M. L., Kostinski, A. B., and Jameson, A. R.: Further evidence for
super terminal drops, Geophys. Res. Lett., 41, 6914–6918,
https://doi.org/10.1002/2014GL061397, 2014.
List, R., Donaldson, N. R., and Stewart, R. E.: Temporal evolution of drop
spectra to collisional equilibrium in steady and pulsating rain, J. Atmos.
Sci., 44, 362–372,
https://doi.org/10.1175/1520-0469(1987)044<0362:TEODST>2.0.CO;2,
1987.
Löffler-Mang, M. and Joss, J.: An optical disdrometer for measuring size
and velocity of hydrometeors, J. Atmos. Ocean. Tech., 17, 130–139,
https://doi.org/10.1175/1520-0426(2000)017<0130:AODFMS>2.0.CO;2,
2000.
Montero-Martinez, G. and Garcia-Garcia, F.: On the behavior of raindrop fall
speed due to wind, Q. J. Roy. Meteor. Soc., 142, 2794, https://doi.org/10.1002/qj.2794,
2016.
Montero-Martinez, G., Kostinski, A. B., Shaw, R. A., and Garcia-Garcia, F.:
Do all raindrops fall at terminal speed?, Geophys. Res. Lett., 36, L11818,
https://doi.org/10.1029/2008GL037111, 2009.
Notaroš, B., Bringi, V. N., Kleinkort, C., Kennedy, P., Huang, G.-J.,
Thurai, M., Newman, A. J., Bang, W., and Lee, G.: Accurate characterization
of winter precipitation using multi-angle snowflake camera, visual hull,
advanced scattering methods and polarimetric radar, Atmosphere, 7, 81–111,
https://doi.org/10.3390/atmos7060081, 2016.
Rasmussen, R., Baker, B., Kochendorfer, J., Meyers, T., Landolt, S.,
Fischer, A. P., Black, J., Thériault, J. M., Kucera, P., Gochis, D.,
Smith, C., Nitu, R., Hall, M., Ikeda, K., and Gutmann, E.: How well are we
measuring snow: the NOAA/FAA/NCAR winter precipitation test bed, B. Am.
Meteorol. Soc., 93, 811–829, https://doi.org/10.1175/BAMS-D-11-00052.1, 2012.
Rosewell, C. J.: Rainfall kinetic energy in Eastern Australia, J. Clim. Appl.
Meteorol., 25, 1695–1701,
https://doi.org/10.1175/1520-0450(1986)025<1695:RKEIEA>2.0.CO;2,
1986.
Schönhuber, M., Lammer, G., and Randeu, W. L.: One decade of imaging
precipitation measurement by 2D-video-distrometer, Adv. Geosci., 10, 85–90,
https://doi.org/10.5194/adgeo-10-85-2007, 2007.
Schönhuber, M., Lammar, G., and Randeu, W. L.: The 2-D-video-distrometer,
in: Precipitation: Advances in Measurement, Estimation and Prediction, edited
by: Michaelides, S. C., Springer, Berlin, Heidelberg, Germany, 3–31, 2008.
Sekhon, R. S. and Srivastava, R. C.: Doppler radar observations of drop-size
distributions in a thunderstorm, J. Atmos. Sci., 28, 983–994,
https://doi.org/10.1175/1520-0469(1971)028<0983:DROODS>2.0.CO;2,
1971.
Stout, J. E., Arya, S. P., and Genikhovich, E. L.: The effect of nonlinear
drag on the motion and settling velocity of heavy particles, J. Atmos. Sci.,
52, 3836–3848,
https://doi.org/10.1175/1520-0469(1995)052<3836:TEONDO>2.0.CO;2,
1995.
Testik, F. Y. and Rahman, M. K.: High-speed optical disdrometer for rainfall
microphysical observations, J. Atmos. Ocean. Tech., 33, 231–243,
https://doi.org/10.1175/JTECH-D-15-0098.1, 2016.
Thériault, J. M., Rasmussen, R., Petro, E., Trépanier, J., Colli, M.,
and Lanza, L. G.: Impact of Wind Direction, Wind Speed, and Particle
Characteristics on the Collection Efficiency of the Double Fence
Intercomparison Reference, J. Appl. Meteorol. Clim., 54, 1918–1930,
https://doi.org/10.1175/JAMC-D-15-0034.1, 2015.
Thurai, M., Huang, G.-J., Bringi, V. N., Randeu, W. L., and Schönhuber,
M.: Drop Shapes, Model Comparisons, and Calculations of Polarimetric Radar
Parameters in Rain, J. Atmos. Ocean. Tech., 24, 1019–1032,
https://doi.org/10.1175/JTECH2051.1, 2007.
Thurai, M., Bringi, V. N., Szakáll, M., Mitra, S. K., Beard, K. V., and
Borrmann, S.: Drop shapes and axis ratio distributions: comparison between
2-D video disdrometer and wind-tunnel measurements, J. Atmos. Ocean. Tech.,
26, 1427–1432, https://doi.org/10.1175/2009TECHA1244.1, 2009.
Thurai, M., Bringi, V. N., Petersen, W. A., and Gatlin, P. N.: Drop shapes
and fall speeds in rain: two contrasting examples, J. Appl. Meteorol. Clim.,
52, 2567–2581, https://doi.org/10.1175/JAMC-D-12-085.1, 2013.
Thurai, M., Gatlin, P., Bringi, V. N., Petersen, W., Kennedy, P.,
Notaroš, B., and Carey, L.: Toward completing the raindrops size
spectrum: case studies involving 2-D-video disdrometer, droplet spectrometer,
and polarimetric radar measurements, J. Appl. Meteorol. Clim., 56, 877–896,
https://doi.org/10.1175/JAMC-D-16-0304.1, 2017.
Trewartha, G. T. and Horn, L. H.: Introduction to Climate, 5th ed,. McGraw
Hill, New York, USA, 416 pp., 1980.
Yu, C.-K., Hsieh, P.-R., Yuter, S. E., Cheng, L.-W., Tsai, C.-L., Lin, C.-Y.,
and Chen, Y.: Measuring droplet fall speed with a high-speed camera: indoor
accuracy and potential outdoor applications, Atmos. Meas. Tech., 9,
1755–1766, https://doi.org/10.5194/amt-9-1755-2016, 2016.
Short summary
Raindrop fall velocities are important for rain rate estimation, soil erosion studies and in numerical modelling of rain formation in clouds. The assumption that the fall velocity is uniquely related to drop size is made inherently based on laboratory measurements under still air conditions from nearly 68 years ago. There have been very few measurements of drop fall speeds in natural rain under both still and turbulent wind conditions. We report on fall speed measurements in natural rain shafts.
Raindrop fall velocities are important for rain rate estimation, soil erosion studies and in...