Articles | Volume 17, issue 20
https://doi.org/10.5194/amt-17-6047-2024
© Author(s) 2024. 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-17-6047-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
17 Oct 2024
Research article |
| 17 Oct 2024
| 17 Oct 2024
Lower-cost eddy covariance for CO2 and H2O fluxes over grassland and agroforestry
Justus G. V. van Ramshorst
CORRESPONDING AUTHOR
Bioclimatology, Faculty of Forest Sciences and Forest Ecology, University of Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
Quanterra Systems Ltd., Centenary House, Peninsula Park, Exeter, EX2 7XE, UK
Alexander Knohl
Bioclimatology, Faculty of Forest Sciences and Forest Ecology, University of Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
Centre of Biodiversity and Sustainable Land Use (CBL), University of Göttingen, 37077 Göttingen, Germany
José Ángel Callejas-Rodelas
Bioclimatology, Faculty of Forest Sciences and Forest Ecology, University of Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
Robert Clement
Quanterra Systems Ltd., Centenary House, Peninsula Park, Exeter, EX2 7XE, UK
Department of Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4RJ, UK
Timothy C. Hill
Department of Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4RJ, UK
Lukas Siebicke
Bioclimatology, Faculty of Forest Sciences and Forest Ecology, University of Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
Christian Markwitz
Bioclimatology, Faculty of Forest Sciences and Forest Ecology, University of Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
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Justus G. V. van Ramshorst, Miriam Coenders-Gerrits, Bart Schilperoort, Bas J. H. van de Wiel, Jonathan G. Izett, John S. Selker, Chad W. Higgins, Hubert H. G. Savenije, and Nick C. van de Giesen
Atmos. Meas. Tech., 13, 5423–5439, https://doi.org/10.5194/amt-13-5423-2020, https://doi.org/10.5194/amt-13-5423-2020, 2020
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In this work we present experimental results of a novel actively heated fiber-optic (AHFO) observational wind-probing technique. We utilized a controlled wind-tunnel setup to assess both the accuracy and precision of AHFO under a range of operational conditions (wind speed, angles of attack and temperature differences). AHFO has the potential to provide high-resolution distributed observations of wind speeds, allowing for better spatial characterization of fine-scale processes.
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We investigated how the size and diversity of tree patches in Indonesian oil palm landscapes influence the movement of water to the atmosphere and local cooling. Our study shows that larger tree patches increase cooling mainly by supporting greater plant diversity and more complex vegetation structure. These findings suggest that expanding and diversifying tree patches can help manage microclimate and water cycling in agricultural areas.
José Ángel Callejas-Rodelas, Alexander Knohl, Ivan Mammarella, Timo Vesala, Olli Peltola, and Christian Markwitz
EGUsphere, https://doi.org/10.5194/egusphere-2025-810, https://doi.org/10.5194/egusphere-2025-810, 2025
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The spatial variability of CO2 and water vapour exchanges with the atmosphere was quantified above an agroforestry system, and further compared to a monocropping system, using a total of four eddy covariance stations. The variability of fluxes within the agroforestry was found to be as large as the variability between agroforestry and monocropping, induced by the heterogeneity of the site, which highlights the need for replicated measurements above such ecosystems.
Jacob A. Nelson, Sophia Walther, Fabian Gans, Basil Kraft, Ulrich Weber, Kimberly Novick, Nina Buchmann, Mirco Migliavacca, Georg Wohlfahrt, Ladislav Šigut, Andreas Ibrom, Dario Papale, Mathias Göckede, Gregory Duveiller, Alexander Knohl, Lukas Hörtnagl, Russell L. Scott, Jiří Dušek, Weijie Zhang, Zayd Mahmoud Hamdi, Markus Reichstein, Sergio Aranda-Barranco, Jonas Ardö, Maarten Op de Beeck, Dave Billesbach, David Bowling, Rosvel Bracho, Christian Brümmer, Gustau Camps-Valls, Shiping Chen, Jamie Rose Cleverly, Ankur Desai, Gang Dong, Tarek S. El-Madany, Eugenie Susanne Euskirchen, Iris Feigenwinter, Marta Galvagno, Giacomo A. Gerosa, Bert Gielen, Ignacio Goded, Sarah Goslee, Christopher Michael Gough, Bernard Heinesch, Kazuhito Ichii, Marcin Antoni Jackowicz-Korczynski, Anne Klosterhalfen, Sara Knox, Hideki Kobayashi, Kukka-Maaria Kohonen, Mika Korkiakoski, Ivan Mammarella, Mana Gharun, Riccardo Marzuoli, Roser Matamala, Stefan Metzger, Leonardo Montagnani, Giacomo Nicolini, Thomas O'Halloran, Jean-Marc Ourcival, Matthias Peichl, Elise Pendall, Borja Ruiz Reverter, Marilyn Roland, Simone Sabbatini, Torsten Sachs, Marius Schmidt, Christopher R. Schwalm, Ankit Shekhar, Richard Silberstein, Maria Lucia Silveira, Donatella Spano, Torbern Tagesson, Gianluca Tramontana, Carlo Trotta, Fabio Turco, Timo Vesala, Caroline Vincke, Domenico Vitale, Enrique R. Vivoni, Yi Wang, William Woodgate, Enrico A. Yepez, Junhui Zhang, Donatella Zona, and Martin Jung
Biogeosciences, 21, 5079–5115, https://doi.org/10.5194/bg-21-5079-2024, https://doi.org/10.5194/bg-21-5079-2024, 2024
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The movement of water, carbon, and energy from the Earth's surface to the atmosphere, or flux, is an important process to understand because it impacts our lives. Here, we outline a method called FLUXCOM-X to estimate global water and CO2 fluxes based on direct measurements from sites around the world. We go on to demonstrate how these new estimates of net CO2 uptake/loss, gross CO2 uptake, total water evaporation, and transpiration from plants compare to previous and independent estimates.
Yuan Yan, Anne Klosterhalfen, Fernando Moyano, Matthias Cuntz, Andrew C. Manning, and Alexander Knohl
Biogeosciences, 20, 4087–4107, https://doi.org/10.5194/bg-20-4087-2023, https://doi.org/10.5194/bg-20-4087-2023, 2023
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A better understanding of O2 fluxes, their exchange ratios with CO2 and their interrelations with environmental conditions would provide further insights into biogeochemical ecosystem processes. We, therefore, used the multilayer canopy model CANVEG to simulate and analyze the flux exchange for our forest study site for 2012–2016. Based on these simulations, we further successfully tested the application of various micrometeorological methods and the prospects of real O2 flux measurements.
Anas Emad and Lukas Siebicke
Atmos. Meas. Tech., 16, 29–40, https://doi.org/10.5194/amt-16-29-2023, https://doi.org/10.5194/amt-16-29-2023, 2023
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The true eddy accumulation (TEA) method enables measuring atmospheric exchange with slow-response gas analyzers. TEA is formulated assuming ideal conditions with a zero mean vertical wind velocity during the averaging interval. This core assumption is rarely valid under field conditions. Here, we extend the TEA equation to accommodate nonideal conditions. The new equation allows constraining the systematic error term in the measured fluxes and the possibility to minimize or remove it.
Anas Emad and Lukas Siebicke
Atmos. Meas. Tech., 16, 41–55, https://doi.org/10.5194/amt-16-41-2023, https://doi.org/10.5194/amt-16-41-2023, 2023
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A new micrometeorological method to measure atmospheric exchange is proposed, and a prototype sampler is evaluated. The new method, called short-time eddy accumulation, is a variant of the eddy accumulation method, which is suited for use with slow gas analyzers. The new method enables adaptive time-varying accumulation intervals, which brings many advantages to flux measurements such as an improved dynamic range and the ability to run eddy accumulation in a continuous flow-through mode.
Xin Yu, René Orth, Markus Reichstein, Michael Bahn, Anne Klosterhalfen, Alexander Knohl, Franziska Koebsch, Mirco Migliavacca, Martina Mund, Jacob A. Nelson, Benjamin D. Stocker, Sophia Walther, and Ana Bastos
Biogeosciences, 19, 4315–4329, https://doi.org/10.5194/bg-19-4315-2022, https://doi.org/10.5194/bg-19-4315-2022, 2022
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Identifying drought legacy effects is challenging because they are superimposed on variability driven by climate conditions in the recovery period. We develop a residual-based approach to quantify legacies on gross primary productivity (GPP) from eddy covariance data. The GPP reduction due to legacy effects is comparable to the concurrent effects at two sites in Germany, which reveals the importance of legacy effects. Our novel methodology can be used to quantify drought legacies elsewhere.
Florian Ellsäßer, Christian Stiegler, Alexander Röll, Tania June, Hendrayanto, Alexander Knohl, and Dirk Hölscher
Biogeosciences, 18, 861–872, https://doi.org/10.5194/bg-18-861-2021, https://doi.org/10.5194/bg-18-861-2021, 2021
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Recording land surface temperatures using drones offers new options to predict evapotranspiration based on energy balance models. This study compares predictions from three energy balance models with the eddy covariance method. A model II Deming regression indicates interchangeability for latent heat flux estimates from certain modeling methods and eddy covariance measurements. This complements the available methods for evapotranspiration studies by fine grain and spatially explicit assessments.
Jan Pisek, Angela Erb, Lauri Korhonen, Tobias Biermann, Arnaud Carrara, Edoardo Cremonese, Matthias Cuntz, Silvano Fares, Giacomo Gerosa, Thomas Grünwald, Niklas Hase, Michal Heliasz, Andreas Ibrom, Alexander Knohl, Johannes Kobler, Bart Kruijt, Holger Lange, Leena Leppänen, Jean-Marc Limousin, Francisco Ramon Lopez Serrano, Denis Loustau, Petr Lukeš, Lars Lundin, Riccardo Marzuoli, Meelis Mölder, Leonardo Montagnani, Johan Neirynck, Matthias Peichl, Corinna Rebmann, Eva Rubio, Margarida Santos-Reis, Crystal Schaaf, Marius Schmidt, Guillaume Simioni, Kamel Soudani, and Caroline Vincke
Biogeosciences, 18, 621–635, https://doi.org/10.5194/bg-18-621-2021, https://doi.org/10.5194/bg-18-621-2021, 2021
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Understory vegetation is the most diverse, least understood component of forests worldwide. Understory communities are important drivers of overstory succession and nutrient cycling. Multi-angle remote sensing enables us to describe surface properties by means that are not possible when using mono-angle data. Evaluated over an extensive set of forest ecosystem experimental sites in Europe, our reported method can deliver good retrievals, especially over different forest types with open canopies.
Jelka Braden-Behrens, Lukas Siebicke, and Alexander Knohl
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-398, https://doi.org/10.5194/bg-2020-398, 2020
Preprint withdrawn
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We use directly measured isotopic compositions and isoforcing values in combination with meteorological data and PBL height information to gain a better understanding of the variability of the isotopic composition of H2Ov. We directly compare the measured changes in isotopic composition with isoforcing-related changes (driven by local evapotranspiration ET). We conclude that it is important to account for PBL height when interpreting isoforcing data.
Yuan Zhang, Ana Bastos, Fabienne Maignan, Daniel Goll, Olivier Boucher, Laurent Li, Alessandro Cescatti, Nicolas Vuichard, Xiuzhi Chen, Christof Ammann, M. Altaf Arain, T. Andrew Black, Bogdan Chojnicki, Tomomichi Kato, Ivan Mammarella, Leonardo Montagnani, Olivier Roupsard, Maria J. Sanz, Lukas Siebicke, Marek Urbaniak, Francesco Primo Vaccari, Georg Wohlfahrt, Will Woodgate, and Philippe Ciais
Geosci. Model Dev., 13, 5401–5423, https://doi.org/10.5194/gmd-13-5401-2020, https://doi.org/10.5194/gmd-13-5401-2020, 2020
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We improved the ORCHIDEE LSM by distinguishing diffuse and direct light in canopy and evaluated the new model with observations from 159 sites. Compared with the old model, the new model has better sunny GPP and reproduced the diffuse light fertilization effect observed at flux sites. Our simulations also indicate different mechanisms causing the observed GPP enhancement under cloudy conditions at different times. The new model has the potential to study large-scale impacts of aerosol changes.
Christian Markwitz, Alexander Knohl, and Lukas Siebicke
Biogeosciences, 17, 5183–5208, https://doi.org/10.5194/bg-17-5183-2020, https://doi.org/10.5194/bg-17-5183-2020, 2020
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Agroforestry has been shown to alter the microclimate and to lead to higher carbon sequestration above ground and in the soil. In this study, we investigated the impact of agroforestry systems on system-scale evapotranspiration (ET) due to concerns about increased water losses to the atmosphere. Results showed small differences in annual sums of ET over agroforestry relative to monoculture systems, indicating that agroforestry in Germany can be a land use alternative to monoculture agriculture.
Justus G. V. van Ramshorst, Miriam Coenders-Gerrits, Bart Schilperoort, Bas J. H. van de Wiel, Jonathan G. Izett, John S. Selker, Chad W. Higgins, Hubert H. G. Savenije, and Nick C. van de Giesen
Atmos. Meas. Tech., 13, 5423–5439, https://doi.org/10.5194/amt-13-5423-2020, https://doi.org/10.5194/amt-13-5423-2020, 2020
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In this work we present experimental results of a novel actively heated fiber-optic (AHFO) observational wind-probing technique. We utilized a controlled wind-tunnel setup to assess both the accuracy and precision of AHFO under a range of operational conditions (wind speed, angles of attack and temperature differences). AHFO has the potential to provide high-resolution distributed observations of wind speeds, allowing for better spatial characterization of fine-scale processes.
Kurt C. Solander, Brent D. Newman, Alessandro Carioca de Araujo, Holly R. Barnard, Z. Carter Berry, Damien Bonal, Mario Bretfeld, Benoit Burban, Luiz Antonio Candido, Rolando Célleri, Jeffery Q. Chambers, Bradley O. Christoffersen, Matteo Detto, Wouter A. Dorigo, Brent E. Ewers, Savio José Filgueiras Ferreira, Alexander Knohl, L. Ruby Leung, Nate G. McDowell, Gretchen R. Miller, Maria Terezinha Ferreira Monteiro, Georgianne W. Moore, Robinson Negron-Juarez, Scott R. Saleska, Christian Stiegler, Javier Tomasella, and Chonggang Xu
Hydrol. Earth Syst. Sci., 24, 2303–2322, https://doi.org/10.5194/hess-24-2303-2020, https://doi.org/10.5194/hess-24-2303-2020, 2020
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We evaluate the soil moisture response in the humid tropics to El Niño during the three most recent super El Niño events. Our estimates are compared to in situ soil moisture estimates that span five continents. We find the strongest and most consistent soil moisture decreases in the Amazon and maritime southeastern Asia, while the most consistent increases occur over eastern Africa. Our results can be used to improve estimates of soil moisture in tropical ecohydrology models at multiple scales.
Christian Markwitz and Lukas Siebicke
Atmos. Meas. Tech., 12, 4677–4696, https://doi.org/10.5194/amt-12-4677-2019, https://doi.org/10.5194/amt-12-4677-2019, 2019
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Turbulent fluxes are usually measured by the eddy covariance method using a combination of a costly gas analyser and a sonic anemometer. In this paper we present an eddy covariance set-up of low cost to measure evapotranspiration over agricultural fields. The method is shown to be comparable to a conventional eddy covariance set-up and is a viable alternative when spatial replicates are required.
Christian Stiegler, Ana Meijide, Yuanchao Fan, Ashehad Ashween Ali, Tania June, and Alexander Knohl
Biogeosciences, 16, 2873–2890, https://doi.org/10.5194/bg-16-2873-2019, https://doi.org/10.5194/bg-16-2873-2019, 2019
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We show the response of a commercial oil palm plantation in Indonesia to the extreme El Niño–Southern Oscillation (ENSO) event in 2015. Our measurements and model suggest that without human-induced forest fires and related smoke emissions, the observed negative impact on oil palm carbon dioxide greenhouse gas fluxes, carbon accumulation and yield due to ENSO-related drought would have been less pronounced. With respect to climate change we highlight the importance of fire prevention in the area.
Ashehad A. Ali, Yuanchao Fan, Marife D. Corre, Martyna M. Kotowska, Evelyn Hassler, Fernando E. Moyano, Christian Stiegler, Alexander Röll, Ana Meijide, Andre Ringeler, Christoph Leuschner, Tania June, Suria Tarigan, Holger Kreft, Dirk Hölscher, Chonggang Xu, Charles D. Koven, Rosie Fisher, Edzo Veldkamp, and Alexander Knohl
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2018-236, https://doi.org/10.5194/gmd-2018-236, 2018
Revised manuscript not accepted
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We used carbon-use and water-use related datasets of small-holder rubber plantations from Jambi province, Indonesia to develop and calibrate a rubber plant functional type for the Community Land Model (CLM-rubber). Increased sensitivity of stomata to soil water stress and enhanced respiration costs enabled the model to capture the magnitude of transpiration and leaf area index. Including temporal variations in leaf life span enabled the model to better capture the seasonality of leaf litterfall.
Jannis von Buttlar, Jakob Zscheischler, Anja Rammig, Sebastian Sippel, Markus Reichstein, Alexander Knohl, Martin Jung, Olaf Menzer, M. Altaf Arain, Nina Buchmann, Alessandro Cescatti, Damiano Gianelle, Gerard Kiely, Beverly E. Law, Vincenzo Magliulo, Hank Margolis, Harry McCaughey, Lutz Merbold, Mirco Migliavacca, Leonardo Montagnani, Walter Oechel, Marian Pavelka, Matthias Peichl, Serge Rambal, Antonio Raschi, Russell L. Scott, Francesco P. Vaccari, Eva van Gorsel, Andrej Varlagin, Georg Wohlfahrt, and Miguel D. Mahecha
Biogeosciences, 15, 1293–1318, https://doi.org/10.5194/bg-15-1293-2018, https://doi.org/10.5194/bg-15-1293-2018, 2018
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Our work systematically quantifies extreme heat and drought event impacts on gross primary productivity (GPP) and ecosystem respiration globally across a wide range of ecosystems. We show that heat extremes typically increased mainly respiration whereas drought decreased both fluxes. Combined heat and drought extremes had opposing effects offsetting each other for respiration, but there were also strong reductions in GPP and hence the strongest reductions in the ecosystems carbon sink capacity.
Jelka Braden-Behrens, Yuan Yan, and Alexander Knohl
Atmos. Meas. Tech., 10, 4537–4560, https://doi.org/10.5194/amt-10-4537-2017, https://doi.org/10.5194/amt-10-4537-2017, 2017
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Here we present the instrument characteristics and field applicability of
the newly developed Delta Ray analyzer for stable isotope measurements
in CO2. We used this analyzer to measure the concentration and the
isotopic composition of CO2 exchange in a managed beech forest for 3
months in autumn 2015. During this period an early frost event occurred
and our measurements suggest that this short event strongly influenced
the measured isotopic composition of CO2 exchange.
Clifton R. Sabajo, Guerric le Maire, Tania June, Ana Meijide, Olivier Roupsard, and Alexander Knohl
Biogeosciences, 14, 4619–4635, https://doi.org/10.5194/bg-14-4619-2017, https://doi.org/10.5194/bg-14-4619-2017, 2017
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From the analysis of MODIS and Landsat satellite data of the Jambi province in Indonesia, this first study on the effects of oil palm expansion on the surface temperature in Indonesia shows shows a local and regional warming effect caused by the expansion of oil palm plantations and other cash or tree crops between 2000 and 2015. The observed warming effects may affect ecosystem services, reduce water availabilty in the dry period and increase the vulnerability to fires in the province.
Yiying Chen, James Ryder, Vladislav Bastrikov, Matthew J. McGrath, Kim Naudts, Juliane Otto, Catherine Ottlé, Philippe Peylin, Jan Polcher, Aude Valade, Andrew Black, Jan A. Elbers, Eddy Moors, Thomas Foken, Eva van Gorsel, Vanessa Haverd, Bernard Heinesch, Frank Tiedemann, Alexander Knohl, Samuli Launiainen, Denis Loustau, Jérôme Ogée, Timo Vessala, and Sebastiaan Luyssaert
Geosci. Model Dev., 9, 2951–2972, https://doi.org/10.5194/gmd-9-2951-2016, https://doi.org/10.5194/gmd-9-2951-2016, 2016
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In this study, we compiled a set of within-canopy and above-canopy measurements of energy and water fluxes, and used these data to parametrize and validate the new multi-layer energy budget scheme for a range of forest types. An adequate parametrization approach has been presented for the global-scale land surface model (ORCHIDEE-CAN). Furthermore, model performance of the new multi-layer parametrization was compared against the existing single-layer scheme.
A. Collalti, S. Marconi, A. Ibrom, C. Trotta, A. Anav, E. D'Andrea, G. Matteucci, L. Montagnani, B. Gielen, I. Mammarella, T. Grünwald, A. Knohl, F. Berninger, Y. Zhao, R. Valentini, and M. Santini
Geosci. Model Dev., 9, 479–504, https://doi.org/10.5194/gmd-9-479-2016, https://doi.org/10.5194/gmd-9-479-2016, 2016
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This study evaluates the performances of the new version (v.5.1) of 3D-CMCC Forest Ecosystem Model in simulating gross primary productivity (GPP), against eddy covariance GPP data for 10 FLUXNET forest sites across Europe. The model consistently reproduces both in timing and in magnitude daily and monthly GPP variability across all sites, with the exception of the two Mediterranean sites. Inclusion of forest structure within simulation ameliorate in some cases the model output.
Y. Fan, O. Roupsard, M. Bernoux, G. Le Maire, O. Panferov, M. M. Kotowska, and A. Knohl
Geosci. Model Dev., 8, 3785–3800, https://doi.org/10.5194/gmd-8-3785-2015, https://doi.org/10.5194/gmd-8-3785-2015, 2015
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A perennial crop model CLM-Palm is developed, including multilayer structure, phenology, and carbon and nitrogen allocation functions, for modeling an important oil palm agricultural system in the tropical regions. Simulated LAI, yield and NPP were calibrated and validated with multiple sites in Sumatra, Indonesia. The new model allows exploring the effects of tropical land use change, from natural ecosystems to monoculture plantations on carbon, water and energy cycles and regional climate.
A. Olchev, A. Ibrom, O. Panferov, D. Gushchina, H. Kreilein, V. Popov, P. Propastin, T. June, A. Rauf, G. Gravenhorst, and A. Knohl
Biogeosciences, 12, 6655–6667, https://doi.org/10.5194/bg-12-6655-2015, https://doi.org/10.5194/bg-12-6655-2015, 2015
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The time series analysis of the main meteorological parameters and components of CO2 and H2O fluxes showed a high evapotranspiration (ET) and gross primary production (GPP) sensitivity of the tropical rainforest to meteorological variations caused by El Niño-Southern Oscillation (ENSO) events. Incoming solar radiation is the main governing factor that is responsible for ET and GPP variability. Changes in precipitation due to moderate ENSO events did not have any notable effect on ET and GPP.
L. Wingate, J. Ogée, E. Cremonese, G. Filippa, T. Mizunuma, M. Migliavacca, C. Moisy, M. Wilkinson, C. Moureaux, G. Wohlfahrt, A. Hammerle, L. Hörtnagl, C. Gimeno, A. Porcar-Castell, M. Galvagno, T. Nakaji, J. Morison, O. Kolle, A. Knohl, W. Kutsch, P. Kolari, E. Nikinmaa, A. Ibrom, B. Gielen, W. Eugster, M. Balzarolo, D. Papale, K. Klumpp, B. Köstner, T. Grünwald, R. Joffre, J.-M. Ourcival, M. Hellstrom, A. Lindroth, C. George, B. Longdoz, B. Genty, J. Levula, B. Heinesch, M. Sprintsin, D. Yakir, T. Manise, D. Guyon, H. Ahrends, A. Plaza-Aguilar, J. H. Guan, and J. Grace
Biogeosciences, 12, 5995–6015, https://doi.org/10.5194/bg-12-5995-2015, https://doi.org/10.5194/bg-12-5995-2015, 2015
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The timing of plant development stages and their response to climate and management were investigated using a network of digital cameras installed across different European ecosystems. Using the relative red, green and blue content of images we showed that the green signal could be used to estimate the length of the growing season in broadleaf forests. We also developed a model that predicted the seasonal variations of camera RGB signals and how they relate to leaf pigment content and area well.
J. Otto, D. Berveiller, F.-M. Bréon, N. Delpierre, G. Geppert, A. Granier, W. Jans, A. Knohl, A. Kuusk, B. Longdoz, E. Moors, M. Mund, B. Pinty, M.-J. Schelhaas, and S. Luyssaert
Biogeosciences, 11, 2411–2427, https://doi.org/10.5194/bg-11-2411-2014, https://doi.org/10.5194/bg-11-2411-2014, 2014
S. Burri, P. Sturm, U. E. Prechsl, A. Knohl, and N. Buchmann
Biogeosciences, 11, 961–975, https://doi.org/10.5194/bg-11-961-2014, https://doi.org/10.5194/bg-11-961-2014, 2014
W. Yuan, S. Liu, W. Cai, W. Dong, J. Chen, A. Arain, P. D. Blanken, A. Cescatti, G. Wohlfahrt, T. Georgiadis, L. Genesio, D. Gianelle, A. Grelle, G. Kiely, A. Knohl, D. Liu, M. Marek, L. Merbold, L. Montagnani, O. Panferov, M. Peltoniemi, S. Rambal, A. Raschi, A. Varlagin, and J. Xia
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmdd-6-5475-2013, https://doi.org/10.5194/gmdd-6-5475-2013, 2013
Revised manuscript not accepted
J. H. Shim, H. H. Powers, C. W. Meyer, A. Knohl, T. E. Dawson, W. J. Riley, W. T. Pockman, and N. McDowell
Biogeosciences, 10, 4937–4956, https://doi.org/10.5194/bg-10-4937-2013, https://doi.org/10.5194/bg-10-4937-2013, 2013
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OF–CEAS laser spectroscopy to measure water isotopes in dry environments: example of application in Antarctica
Performance evaluation of air quality sensors for environmental epidemiology
Interpretation of mass spectra by a Vocus proton transfer reaction mass spectrometer (PTR-MS) at an urban site: insights from gas-chromatographic pre-separation
Towards a high-quality in situ observation network for oxygenated volatile organic compounds (OVOCs) in Europe: transferring metrological traceability to the field
Improving the quantification of peak concentrations for air quality sensors via data weighting
Improving Consistency in Methane Emission Quantification from the Natural Gas Distribution System across Measurement Devices
Long-term observations of atmospheric CO2 and CH4 trends and comparison of two measurement systems at Pallas-Sammaltunturi station in Northern Finland
Validation of formaldehyde products from three satellite retrievals (OMI SAO, OMPS-NPP SAO, and OMI BIRA) in the marine atmosphere with four seasons of Atmospheric Tomography Mission (ATom) aircraft observations
Methodology and uncertainty estimation for measurements of methane leakage in a manufactured house
Alternate materials for the capture and quantification of gaseous oxidized mercury in the atmosphere
Evaluation of optimized flux chamber design for measurement of ammonia emission after field application of slurry with full-scale farm machinery
Preparation of low-concentration H2 test gas mixtures in ambient air for calibration of H2 sensors
Pico-Light H2O: intercomparison of in situ water vapour measurements during the AsA 2022 campaign
Mobile air quality monitoring and comparison to fixed monitoring sites for instrument performance assessment
Intercomparison of eddy-covariance software for urban tall-tower sites
Assessment of current methane emission quantification techniques for natural gas midstream applications
Performance assessment of state-of-the-art and novel methods for remote compliance monitoring of sulfur emissions from shipping
Intercomparison of detection and quantification methods for methane emissions from the natural gas distribution network in Hamburg, Germany
Comparison of photoacoustic spectroscopy and cavity ring-down spectroscopy for ambient methane monitoring at Hohenpeißenberg
Comparison of atmospheric CO, CO2 and CH4 measurements at the Schneefernerhaus and the mountain ridge at Zugspitze
Intercomparison of commercial analyzers for atmospheric ethane and methane observations
Real-time measurement of phase partitioning of organic compounds using a proton-transfer-reaction time-of-flight mass spectrometer coupled to a CHARON inlet
A quantitative comparison of methods used to measure smaller methane emissions typically observed from superannuated oil and gas infrastructure
Comparing airborne algorithms for greenhouse gas flux measurements over the Alberta oil sands
Characterization of inexpensive metal oxide sensor performance for trace methane detection
Intercomparison of upper tropospheric and lower stratospheric water vapor measurements over the Asian Summer Monsoon during the StratoClim campaign
Air pollution measurement errors: is your data fit for purpose?
Performance characterization of low-cost air quality sensors for off-grid deployment in rural Malawi
Comment on “Comparison of ozone measurement methods in biomass burning smoke: an evaluation under field and laboratory conditions” by Long et al. (2021)
Homogenization of the Observatoire de Haute Provence electrochemical concentration cell (ECC) ozonesonde data record: comparison with lidar and satellite observations
Long-term behavior and stability of calibration models for NO and NO2 low-cost sensors
Controlled-release experiment to investigate uncertainties in UAV-based emission quantification for methane point sources
Ozone formation sensitivity study using machine learning coupled with the reactivity of volatile organic compound species
Evaluating uncertainty in sensor networks for urban air pollution insights
Estimating oil sands emissions using horizontal path-integrated column measurements
Global evaluation of the precipitable-water-vapor product from MERSI-II (Medium Resolution Spectral Imager) on board the Fengyun-3D satellite
Field testing two flux footprint models
Validation of a new cavity ring-down spectrometer for measuring tropospheric gaseous hydrogen chloride
Comparison of formaldehyde measurements by Hantzsch, CRDS and DOAS in the SAPHIR chamber
A field intercomparison of three passive air samplers for gaseous mercury in ambient air
Beef cattle methane emissions measured with tracer-ratio and inverse dispersion modelling techniques
Methane emissions from an oil sands tailings pond: a quantitative comparison of fluxes derived by different methods
Performance of open-path GasFinder3 devices for CH4 concentration measurements close to ambient levels
Water vapor density and turbulent fluxes from three generations of infrared gas analyzers
Quantifying fugitive gas emissions from an oil sands tailings pond with open-path Fourier transform infrared measurements
Robust statistical calibration and characterization of portable low-cost air quality monitoring sensors to quantify real-time O3 and NO2 concentrations in diverse environments
A miniature Portable Emissions Measurement System (PEMS) for real-driving monitoring of motorcycles
In situ measurement of CO2 and CH4 from aircraft over northeast China and comparison with OCO-2 data
Jianqiang Zeng, Yanli Zhang, Haofan Ran, Weihua Pang, Hao Guo, Zhaobin Mu, Wei Song, and Xinming Wang
Atmos. Meas. Tech., 18, 1811–1821, https://doi.org/10.5194/amt-18-1811-2025, https://doi.org/10.5194/amt-18-1811-2025, 2025
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This study revealed the existence of significant species-specific adsorptive and reactive losses of monoterpenes and sesquiterpenes in dynamic chambers. The deuterated α-pinene-d3 and β-caryophyllene-d2 were proven as effective surrogates in tracing these losses for some key monoterpenes and sesquiterpenes. The findings highlight the importance of selecting internal surrogates that closely match the adsorptive and reactive behaviors of target compounds for precise loss correction.
Emily Follansbee, James E. Lee, Mohit L. Dubey, Jonathan F. Dooley, Curtis Shuck, Ken Minschwaner, Andre Santos, Sebastien C. Biraud, and Manvendra K. Dubey
EGUsphere, https://doi.org/10.5194/egusphere-2025-344, https://doi.org/10.5194/egusphere-2025-344, 2025
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This work uses ambient methane and wind measurements to quantify methane emissions from a leaking orphaned oil and gas well using Gaussian plume inversions. Our analysis shows that existing Gaussian plume methods that assume atmospheric stability are prone to large errors. We report a more robust analysis that determines plume dispersion coefficients from our in situ observations. Our technique enables more accurate methane quantification of orphaned oil and gas wells to prioritize plugging.
Thomas Lauwers, Elise Fourré, Olivier Jossoud, Daniele Romanini, Frédéric Prié, Giordano Nitti, Mathieu Casado, Kévin Jaulin, Markus Miltner, Morgane Farradèche, Valérie Masson-Delmotte, and Amaëlle Landais
Atmos. Meas. Tech., 18, 1135–1147, https://doi.org/10.5194/amt-18-1135-2025, https://doi.org/10.5194/amt-18-1135-2025, 2025
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Water vapour isotopes are important tools to better understand processes governing the atmospheric hydrological cycle. In polar regions, their measurement helps to improve the interpretation of water isotopic records in ice cores. However, in situ water vapour isotopic monitoring is an important challenge, especially in dry places of East Antarctica. We present here an alternative laser spectroscopy technique adapted for such measurements, with a limit of detection down to 10 ppm humidity.
Miriam Chacón-Mateos, Héctor García-Salamero, Bernd Laquai, and Ulrich Vogt
EGUsphere, https://doi.org/10.5194/egusphere-2025-587, https://doi.org/10.5194/egusphere-2025-587, 2025
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This study evaluates air quality sensors in indoor & outdoor environments to support health research. Sensors were calibrated using data from reference instruments, and regression and machine learning models were tested for data correction. Results highlight the importance of using high-quality training data during co-location. Integrating metadata, such as activity logs, helps validate calibrated sensor data. These findings can enhance the use of air quality sensors in health studies globally.
Ying Zhang, Yuwei Wang, Chuang Li, Yueyang Li, Sijia Yin, Megan S. Claflin, Brian M. Lerner, Douglas Worsnop, and Lin Wang
EGUsphere, https://doi.org/10.5194/egusphere-2025-757, https://doi.org/10.5194/egusphere-2025-757, 2025
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This study provides insight into how individual ions measured by proton transfer reaction-mass spectrometry are produced by multiple volatile organic compounds. A reference table is provided for attributing the PTR signal to contributing VOC species. The signals are grouped according to the complexity of their potential identities. We find that a number of signal ions such as C6H7+ for benzene and C5H9+ for isoprene merely give an upper limit of their corresponding concentration.
Maitane Iturrate-Garcia, Thérèse Salameh, Paul Schlauri, Annarita Baldan, Martin K. Vollmer, Evdokia Stratigou, Sebastien Dusanter, Jianrong Li, Stefan Persijn, Anja Claude, Rupert Holzinger, Christophe Sutour, Tatiana Macé, Yasin Elshorbany, Andreas Ackermann, Céline Pascale, and Stefan Reimann
Atmos. Meas. Tech., 18, 371–403, https://doi.org/10.5194/amt-18-371-2025, https://doi.org/10.5194/amt-18-371-2025, 2025
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Accurate and comparable measurements of oxygenated organic compounds (OVOCs) are crucial in assessing tropospheric ozone burdens and trends. However, the monitoring of many OVOCs remains challenging because of their low atmospheric abundance and lack of stable and traceable calibration standards. This paper describes the calibration standards developed for OVOCs at a low amount of substance fractions (<100 nmol mol-1) to transfer traceability of the International System of Units to the field.
Caroline Frischmon, Jon Silberstein, Annamarie Guth, Erick Mattson, Jack Porter, and Michael Hannigan
EGUsphere, https://doi.org/10.5194/egusphere-2024-4080, https://doi.org/10.5194/egusphere-2024-4080, 2025
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Air quality sensors often under-predict peak concentrations, which is a major issue in applications such as emissions event detection. This manuscript details a novel approach involving data weighting to improve quantification of these peak concentrations. To demonstrate its effectiveness, we applied data weighting to carbon monoxide, methane, and VOC sensor data. This work broadens our ability to use air sensors in contexts where accurate quantification of peak concentrations is essential.
Judith Tettenborn, Daniel Zavala-Araiza, Daan Stroeken, Hossein Maazallahi, Carina van der Veen, Arjan Hensen, Ilona Velzeboer, Pim van den Bulk, Felix Vogel, Lawson Gillespie, Sebastien Ars, James France, David Lowry, Rebecca Fisher, and Thomas Röckmann
EGUsphere, https://doi.org/10.5194/egusphere-2024-3620, https://doi.org/10.5194/egusphere-2024-3620, 2025
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Measurements of methane with vehicle-based sensors are an effective method to identify and quantify leaks from urban gas distribution systems. We deliberately released methane in different environments, and calibrated the response of different methane analyzers when they transect the plumes in a vehicle. We derived an improved statistical function for consistent emission estimations using different instruments. Repeated transects reduce the uncertainty in emission rate estimates.
Antti Laitinen, Hermanni Aaltonen, Christoph Zellweger, Aki Tsuruta, Tuula Aalto, and Juha Hatakka
EGUsphere, https://doi.org/10.5194/egusphere-2024-3941, https://doi.org/10.5194/egusphere-2024-3941, 2025
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This article presents the time series of CO2 and CH4 mixing ratios measured at Pallas station in Finland over long time period. In addition, two instruments measuring both species were compared against each other over as well as against separate audit instruments over 6 week period. The mixing ratios of both species show growth comparable to the average in the Northern Hemisphere. The differences between the instruments are small and fit within the compatibility goals assigned by WMO.
Jin Liao, Glenn M. Wolfe, Alexander E. Kotsakis, Julie M. Nicely, Jason M. St. Clair, Thomas F. Hanisco, Gonzalo González Abad, Caroline R. Nowlan, Zolal Ayazpour, Isabelle De Smedt, Eric C. Apel, and Rebecca S. Hornbrook
Atmos. Meas. Tech., 18, 1–16, https://doi.org/10.5194/amt-18-1-2025, https://doi.org/10.5194/amt-18-1-2025, 2025
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Validation of satellite HCHO over the remote marine regions is relatively low, and modeled HCHO in these regions is usually added as a global satellite HCHO background. This paper intercompares three satellite HCHO retrievals and validates them against in situ observations from the NASA ATom mission. All retrievals are correlated with ATom-integrated columns over remote oceans, with OMI SAO (v004) showing the best agreement. A persistent low bias is found in all retrievals at high latitudes.
Anna Karion, Michael F. Link, Rileigh Robertson, Tyler Boyle, and Dustin Poppendieck
Atmos. Meas. Tech., 17, 7065–7075, https://doi.org/10.5194/amt-17-7065-2024, https://doi.org/10.5194/amt-17-7065-2024, 2024
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Methane leaks into houses that use natural gas from appliances, pipes, and fittings. We measured methane emitted from a manufactured house under different ventilation conditions using indoor and outdoor concentration measurements. We injected methane at prescribed rates into the house and then measured the emissions using our method. We report the error in the calculation based on these tests. We also describe the method and provide guidance on conducting this type of experiment.
Livia Lown, Sarrah M. Dunham-Cheatham, Seth N. Lyman, and Mae S. Gustin
Atmos. Meas. Tech., 17, 6397–6413, https://doi.org/10.5194/amt-17-6397-2024, https://doi.org/10.5194/amt-17-6397-2024, 2024
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New sorbent materials are needed to preconcentrate atmospheric oxidized mercury for analysis by developing mass spectrometry methods. Chitosan, α-Al2O3, and γ-Al2O3 were tested for quantitative gaseous oxidized mercury sorption in ambient air under laboratory and field conditions. Although these materials sorbed gaseous oxidized mercury without sorbing elemental mercury in the laboratory, less oxidized mercury was recovered from these materials compared to cation exchange membranes in the field.
Johanna Pedersen, Sasha D. Hafner, Andreas Pacholski, Valthor I. Karlsson, Li Rong, Rodrigo Labouriau, and Jesper N. Kamp
Atmos. Meas. Tech., 17, 4493–4505, https://doi.org/10.5194/amt-17-4493-2024, https://doi.org/10.5194/amt-17-4493-2024, 2024
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Field-applied animal slurry is a significant source of NH3 emission. A new system of dynamic flux chambers for NH3 measurements was developed and validated using three field trials in order to assess the variability after application with a trailing hose at different scales: manual (handheld) application, a 3 m slurry boom, and a 30 m slurry boom. The system facilitates NH3 emission measurement with replication after both manual and farm-scale slurry application with relatively high precision.
Niklas Karbach, Lisa Höhler, Peter Hoor, Heiko Bozem, Nicole Bobrowski, and Thorsten Hoffmann
Atmos. Meas. Tech., 17, 4081–4086, https://doi.org/10.5194/amt-17-4081-2024, https://doi.org/10.5194/amt-17-4081-2024, 2024
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The system presented here can accurately generate and reproduce a stable flow of gas mixtures of known concentrations over several days using ambient air as a dilution medium. In combination with the small size and low weight of the system, this enables the calibration of hydrogen sensors in the field, reducing the influence of matrix effects on the accuracy of the sensor. The system is inexpensive to assemble and easy to maintain, which is the key to reliable measurement results.
Mélanie Ghysels, Georges Durry, Nadir Amarouche, Dale Hurst, Emrys Hall, Kensy Xiong, Jean-Charles Dupont, Jean-Christophe Samake, Fabien Frérot, Raghed Bejjani, and Emmanuel D. Riviere
Atmos. Meas. Tech., 17, 3495–3513, https://doi.org/10.5194/amt-17-3495-2024, https://doi.org/10.5194/amt-17-3495-2024, 2024
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A tunable diode laser hygrometer, “Pico-Light H2O”, is presented and its performances are evaluated during the AsA 2022 balloon-borne intercomparison campaign from Aire-sur-l'Adour (France) in September 2022. A total of 15 balloons were launched within the framework of the EU-funded HEMERA project. Pico-Light H2O has been compared in situ with the NOAA Frost Point Hygrometer in the upper troposphere and stratosphere, as well as with meteorological sondes (iMet-4 and M20) in the troposphere.
Andrew R. Whitehill, Melissa Lunden, Brian LaFranchi, Surender Kaushik, and Paul A. Solomon
Atmos. Meas. Tech., 17, 2991–3009, https://doi.org/10.5194/amt-17-2991-2024, https://doi.org/10.5194/amt-17-2991-2024, 2024
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We present an analysis from two large-scale mobile air quality monitoring campaigns in Colorado and California. We compare mobile measurements of air quality to measurements from nearby regulatory sites. The goal of this paper is to explore how fixed-site measurements (such as regulatory site measurements) can be used for ongoing instrument performance assessment of mobile monitoring platforms over extended measurement campaigns.
Changxing Lan, Matthias Mauder, Stavros Stagakis, Benjamin Loubet, Claudio D'Onofrio, Stefan Metzger, David Durden, and Pedro-Henrique Herig-Coimbra
Atmos. Meas. Tech., 17, 2649–2669, https://doi.org/10.5194/amt-17-2649-2024, https://doi.org/10.5194/amt-17-2649-2024, 2024
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Using eddy-covariance systems deployed in three cities, we aimed to elucidate the sources of discrepancies in flux estimations from different software packages. One crucial finding is the impact of low-frequency spectral loss corrections on tall-tower flux estimations. Our findings emphasize the significance of a standardized measurement setup and consistent postprocessing configurations in minimizing the systematic flux uncertainty resulting from the usage of different software packages.
Yunsong Liu, Jean-Daniel Paris, Gregoire Broquet, Violeta Bescós Roy, Tania Meixus Fernandez, Rasmus Andersen, Andrés Russu Berlanga, Emil Christensen, Yann Courtois, Sebastian Dominok, Corentin Dussenne, Travis Eckert, Andrew Finlayson, Aurora Fernández de la Fuente, Catlin Gunn, Ram Hashmonay, Juliano Grigoleto Hayashi, Jonathan Helmore, Soeren Honsel, Fabrizio Innocenti, Matti Irjala, Torgrim Log, Cristina Lopez, Francisco Cortés Martínez, Jonathan Martinez, Adrien Massardier, Helle Gottschalk Nygaard, Paula Agregan Reboredo, Elodie Rousset, Axel Scherello, Matthias Ulbricht, Damien Weidmann, Oliver Williams, Nigel Yarrow, Murès Zarea, Robert Ziegler, Jean Sciare, Mihalis Vrekoussis, and Philippe Bousquet
Atmos. Meas. Tech., 17, 1633–1649, https://doi.org/10.5194/amt-17-1633-2024, https://doi.org/10.5194/amt-17-1633-2024, 2024
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We investigated the performance of 10 methane emission quantification techniques in a blind controlled-release experiment at an inerted natural gas compressor station. We reported their respective strengths, weaknesses, and potential complementarity depending on the emission rates and atmospheric conditions. Additionally, we assess the dependence of emission quantification performance on key parameters such as wind speed, deployment constraints, and measurement duration.
Jörg Beecken, Andreas Weigelt, Simone Griesel, Johan Mellqvist, Alexander V. Conde Jacobo, Daniëlle van Dinther, Jan Duyzer, Jon Knudsen, Bettina Knudsen, and Leonidas Ntziachristos
Atmos. Meas. Tech., 16, 5883–5895, https://doi.org/10.5194/amt-16-5883-2023, https://doi.org/10.5194/amt-16-5883-2023, 2023
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Air pollution from shipping is a debated topic in science and politics. We compare different monitoring systems currently used in different European countries for the enforcement of emission limits regarding air pollution from ships according to regulation. The system performances were individually assessed in the field by comparison with true values. Non-compliant vessels with actual fuel sulfur contents > 0.15–0.19 % Sm/m can be detected by the compared systems with 95 % confidence.
Hossein Maazallahi, Antonio Delre, Charlotte Scheutz, Anders M. Fredenslund, Stefan Schwietzke, Hugo Denier van der Gon, and Thomas Röckmann
Atmos. Meas. Tech., 16, 5051–5073, https://doi.org/10.5194/amt-16-5051-2023, https://doi.org/10.5194/amt-16-5051-2023, 2023
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Measurement methods are increasingly deployed to verify reported methane emissions of gas leaks. This study describes unique advantages and limitations of three methods. Two methods are rapidly deployed, but uncertainties and biases exist for some leak locations. In contrast, the suction method could accurately determine leak rates in principle. However, this method, which provides data for the German emission inventory, creates an overall low bias in our study due to non-random site selection.
Max Müller, Stefan Weigl, Jennifer Müller-Williams, Matthias Lindauer, Thomas Rück, Simon Jobst, Rudolf Bierl, and Frank-Michael Matysik
Atmos. Meas. Tech., 16, 4263–4270, https://doi.org/10.5194/amt-16-4263-2023, https://doi.org/10.5194/amt-16-4263-2023, 2023
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Over a period of 5 d, a photoacoustic methane sensor was compared with a Picarro cavity ring-down (G2301) spectrometer. Both devices measured the ambient methane concentration at the meteorological observatory Hohenpeißenberg. Cross-sensitivities on the photoacoustic signal, due to fluctuating ambient humidity, were compensated by applying the CoNRad algorithm. The results show that photoacoustic sensors have the potential for accurate and precise greenhouse gas monitoring.
Antje Hoheisel, Cedric Couret, Bryan Hellack, and Martina Schmidt
Atmos. Meas. Tech., 16, 2399–2413, https://doi.org/10.5194/amt-16-2399-2023, https://doi.org/10.5194/amt-16-2399-2023, 2023
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High-precision CO2, CH4 and CO measurements have been carried out at Zugspitze for decades. New technologies make it possible to analyse these gases with high temporal resolution. This allows the detection of local pollution. To this end, measurements have been performed on the mountain ridge (ZGR) and are compared to routine measurements at the Schneefernerhaus (ZSF). Careful manual flagging of pollution events in the ZSF data leads to consistency with the little influenced ZGR time series.
Róisín Commane, Andrew Hallward-Driemeier, and Lee T. Murray
Atmos. Meas. Tech., 16, 1431–1441, https://doi.org/10.5194/amt-16-1431-2023, https://doi.org/10.5194/amt-16-1431-2023, 2023
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Methane / ethane ratios can be used to identify and partition the different sources of methane, especially in areas with natural gas mixed with biogenic methane emissions, such as cities. We tested three commercially available laser-based analyzers for sensitivity, precision, size, power requirement, ease of use on mobile platforms, and expertise needed to operate the instrument, and we make recommendations for use in various situations.
Yarong Peng, Hongli Wang, Yaqin Gao, Shengao Jing, Shuhui Zhu, Dandan Huang, Peizhi Hao, Shengrong Lou, Tiantao Cheng, Cheng Huang, and Xuan Zhang
Atmos. Meas. Tech., 16, 15–28, https://doi.org/10.5194/amt-16-15-2023, https://doi.org/10.5194/amt-16-15-2023, 2023
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This work examined the phase partitioning behaviors of organic compounds at hourly resolution in ambient conditions with the use of the CHemical Analysis of aeRosols ONline (CHARON) inlet coupled to a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS). Properly accounting for the neutral losses of small moieties during the molecular feature extraction from PTR mass spectra could significantly reduce uncertainties associated with the gas–particle partitioning measurements.
Stuart N. Riddick, Riley Ancona, Mercy Mbua, Clay S. Bell, Aidan Duggan, Timothy L. Vaughn, Kristine Bennett, and Daniel J. Zimmerle
Atmos. Meas. Tech., 15, 6285–6296, https://doi.org/10.5194/amt-15-6285-2022, https://doi.org/10.5194/amt-15-6285-2022, 2022
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This describes controlled release experiments at the METEC facility in Fort Collins, USA, that investigates the accuracy and precision of five methods commonly used to measure methane emissions. Methods include static/dynamic chambers, hi flow sampling, a backward Lagrangian stochastic method, and a Gaussian plume method. This is the first time that methods for measuring CH4 emissions from point sources less than 200 g CH4 h−1 have been quantitively assessed against references and each other.
Broghan M. Erland, Cristen Adams, Andrea Darlington, Mackenzie L. Smith, Andrew K. Thorpe, Gregory R. Wentworth, Steve Conley, John Liggio, Shao-Meng Li, Charles E. Miller, and John A. Gamon
Atmos. Meas. Tech., 15, 5841–5859, https://doi.org/10.5194/amt-15-5841-2022, https://doi.org/10.5194/amt-15-5841-2022, 2022
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Accurately estimating greenhouse gas (GHG) emissions is essential to reaching net-zero goals to combat the climate crisis. Airborne box-flights are ideal for assessing regional GHG emissions, as they can attain small error. We compare two box-flight algorithms and found they produce similar results, but daily variability must be considered when deriving emissions inventories. Increasing the consistency and agreement between airborne methods moves us closer to achieving more accurate estimates.
Daniel Furuta, Tofigh Sayahi, Jinsheng Li, Bruce Wilson, Albert A. Presto, and Jiayu Li
Atmos. Meas. Tech., 15, 5117–5128, https://doi.org/10.5194/amt-15-5117-2022, https://doi.org/10.5194/amt-15-5117-2022, 2022
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Methane is a major greenhouse gas and contributor to climate change with various human-caused and natural sources. Currently, atmospheric methane is expensive to sense. We investigate repurposing cheap methane safety sensors for atmospheric sensing, finding several promising sensors and identifying some of the challenges in this approach. This work will help in developing inexpensive sensor networks for methane monitoring, which will aid in reducing methane leaks and emissions.
Clare E. Singer, Benjamin W. Clouser, Sergey M. Khaykin, Martina Krämer, Francesco Cairo, Thomas Peter, Alexey Lykov, Christian Rolf, Nicole Spelten, Armin Afchine, Simone Brunamonti, and Elisabeth J. Moyer
Atmos. Meas. Tech., 15, 4767–4783, https://doi.org/10.5194/amt-15-4767-2022, https://doi.org/10.5194/amt-15-4767-2022, 2022
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In situ measurements of water vapor in the upper troposphere are necessary to study cloud formation and hydration of the stratosphere but challenging due to cold–dry conditions. We compare measurements from three water vapor instruments from the StratoClim campaign in 2017. In clear sky (clouds), point-by-point differences were <1.5±8 % (<1±8 %). This excellent agreement allows detection of fine-scale structures required to understand the impact of convection on stratospheric water vapor.
Sebastian Diez, Stuart E. Lacy, Thomas J. Bannan, Michael Flynn, Tom Gardiner, David Harrison, Nicholas Marsden, Nicholas A. Martin, Katie Read, and Pete M. Edwards
Atmos. Meas. Tech., 15, 4091–4105, https://doi.org/10.5194/amt-15-4091-2022, https://doi.org/10.5194/amt-15-4091-2022, 2022
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Regardless of the cost of the measuring instrument, there are no perfect measurements. For this reason, we compare the quality of the information provided by cheap devices when they are used to measure air pollutants and we try to emphasise that before judging the potential usefulness of the devices, the user must specify his own needs. Since commonly used performance indices/metrics can be misleading in qualifying this, we propose complementary visual analysis to the more commonly used metrics.
Ashley S. Bittner, Eben S. Cross, David H. Hagan, Carl Malings, Eric Lipsky, and Andrew P. Grieshop
Atmos. Meas. Tech., 15, 3353–3376, https://doi.org/10.5194/amt-15-3353-2022, https://doi.org/10.5194/amt-15-3353-2022, 2022
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We present findings from a 1-year pilot deployment of low-cost integrated air quality sensor packages in rural Malawi using calibration models developed during collocation with US regulatory monitors. We compare the results with data from remote sensing products and previous field studies. We conclude that while the remote calibration approach can help extract useful data, great care is needed when assessing low-cost sensor data collected in regions without reference instrumentation.
Noah Bernays, Daniel A. Jaffe, Irina Petropavlovskikh, and Peter Effertz
Atmos. Meas. Tech., 15, 3189–3192, https://doi.org/10.5194/amt-15-3189-2022, https://doi.org/10.5194/amt-15-3189-2022, 2022
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Ozone is an important pollutant that impacts millions of people worldwide. It is therefore important to ensure accurate measurements. A recent surge in wildfire activity in the USA has resulted in significant enhancements in ozone concentration. However given the nature of wildfire smoke, there are questions about our ability to accurately measure ozone. In this comment, we discuss possible biases in the UV measurements of ozone in the presence of smoke.
Gérard Ancellet, Sophie Godin-Beekmann, Herman G. J. Smit, Ryan M. Stauffer, Roeland Van Malderen, Renaud Bodichon, and Andrea Pazmiño
Atmos. Meas. Tech., 15, 3105–3120, https://doi.org/10.5194/amt-15-3105-2022, https://doi.org/10.5194/amt-15-3105-2022, 2022
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The 1991–2021 Observatoire de Haute Provence electrochemical concentration cell (ECC) ozonesonde data have been homogenized according to the recommendations of the Ozonesonde Data Quality Assessment panel. Comparisons with ground-based instruments also measuring ozone at the same station (lidar, surface measurements) and with colocated satellite observations show the benefits of this homogenization. Remaining differences between ECC and other observations in the stratosphere are also discussed.
Horim Kim, Michael Müller, Stephan Henne, and Christoph Hüglin
Atmos. Meas. Tech., 15, 2979–2992, https://doi.org/10.5194/amt-15-2979-2022, https://doi.org/10.5194/amt-15-2979-2022, 2022
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In this study, the performance of electrochemical sensors for NO and NO2 for measuring air quality was determined over a longer operating period. The performance of NO sensors remained reliable for more than 18 months. However, the NO2 sensors showed decreasing performance over time. During deployment, we found that the NO2 sensors can distinguish general pollution levels, but they proved unsuitable for accurate measurements due to significant biases.
Randulph Morales, Jonas Ravelid, Katarina Vinkovic, Piotr Korbeń, Béla Tuzson, Lukas Emmenegger, Huilin Chen, Martina Schmidt, Sebastian Humbel, and Dominik Brunner
Atmos. Meas. Tech., 15, 2177–2198, https://doi.org/10.5194/amt-15-2177-2022, https://doi.org/10.5194/amt-15-2177-2022, 2022
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Mapping trace gas emission plumes using in situ measurements from unmanned aerial vehicles (UAVs) is an emerging and attractive possibility to quantify emissions from localized sources. We performed an extensive controlled-release experiment to develop an optimal quantification method and to determine the related uncertainties under various environmental and sampling conditions. Our approach was successful in quantifying local methane sources from drone-based measurements.
Junlei Zhan, Yongchun Liu, Wei Ma, Xin Zhang, Xuezhong Wang, Fang Bi, Yujie Zhang, Zhenhai Wu, and Hong Li
Atmos. Meas. Tech., 15, 1511–1520, https://doi.org/10.5194/amt-15-1511-2022, https://doi.org/10.5194/amt-15-1511-2022, 2022
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Our study investigated the O3 formation sensitivity in Beijing using a random forest model coupled with the reactivity of volatile organic
compound (VOC) species. Results found that random forest accurately predicted O3 concentration when initial VOCs were considered, and relative importance correlated well with O3 formation potential. The O3 isopleth curves calculated by the random forest model were generally comparable with those calculated by the box model.
Daniel R. Peters, Olalekan A. M. Popoola, Roderic L. Jones, Nicholas A. Martin, Jim Mills, Elizabeth R. Fonseca, Amy Stidworthy, Ella Forsyth, David Carruthers, Megan Dupuy-Todd, Felicia Douglas, Katie Moore, Rishabh U. Shah, Lauren E. Padilla, and Ramón A. Alvarez
Atmos. Meas. Tech., 15, 321–334, https://doi.org/10.5194/amt-15-321-2022, https://doi.org/10.5194/amt-15-321-2022, 2022
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We present more than 2 years of NO2 pollution measurements from a sensor network in Greater London and compare results to an extensive network of expensive reference-grade monitors. We show the ability of our lower-cost network to generate robust insights about local air pollution. We also show how irregularities in sensor performance lead to some uncertainty in results and demonstrate ways that future users can characterize and mitigate uncertainties to get the most value from sensor data.
Timothy G. Pernini, T. Scott Zaccheo, Jeremy Dobler, and Nathan Blume
Atmos. Meas. Tech., 15, 225–240, https://doi.org/10.5194/amt-15-225-2022, https://doi.org/10.5194/amt-15-225-2022, 2022
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We demonstrate a novel approach to estimating emissions from oil sands operations that utilizes the GreenLITE™ gas concentration measurement system and an atmospheric model. While deployed at a facility in the Athabasca region of Alberta, Canada, CH4 emissions from a tailings pond were estimated to be 7.2 t/d for July–October 2019, and 5.1 t/d for March–July 2020. CH4 emissions from an open-pit mine were estimated to be 24.6 t/d for September–October 2019.
Wengang Zhang, Ling Wang, Yang Yu, Guirong Xu, Xiuqing Hu, Zhikang Fu, and Chunguang Cui
Atmos. Meas. Tech., 14, 7821–7834, https://doi.org/10.5194/amt-14-7821-2021, https://doi.org/10.5194/amt-14-7821-2021, 2021
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Global precipitable water vapor (PWV) derived from MERSI-II (Medium Resolution Spectral Imager) is compared with PWV from the Integrated Global Radiosonde Archive (IGRA). Our results show a good agreement between PWV from MERSI-II and IGRA and that MERSI-II PWV is slightly underestimated on the whole, especially in summer. The bias between MERSI-II and IGRA grows with a larger spatial distance between the footprint of the satellite and the IGRA station, as well as increasing PWV.
Trevor W. Coates, Monzurul Alam, Thomas K. Flesch, and Guillermo Hernandez-Ramirez
Atmos. Meas. Tech., 14, 7147–7152, https://doi.org/10.5194/amt-14-7147-2021, https://doi.org/10.5194/amt-14-7147-2021, 2021
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A field study tested two footprint models for calculating surface emissions from downwind flux measurements. Emission rates from a 10 × 10 m synthetic source were estimated with the simple Kormann–Meixner model and a sophisticated Lagrangian stochastic model. Both models underestimated emissions by approximately 30 %, and no statistical differences were observed between the models. Footprint models are critically important for interpreting eddy covariance measurements.
Teles C. Furlani, Patrick R. Veres, Kathryn E. R. Dawe, J. Andrew Neuman, Steven S. Brown, Trevor C. VandenBoer, and Cora J. Young
Atmos. Meas. Tech., 14, 5859–5871, https://doi.org/10.5194/amt-14-5859-2021, https://doi.org/10.5194/amt-14-5859-2021, 2021
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This study characterized and validated a commercial spectroscopic instrument for the measurement of hydrogen chloride (HCl) in the atmosphere. Near the Earth’s surface, HCl acts as the dominant reservoir for other chlorine-containing reactive chemicals that play an important role in atmospheric chemistry. The properties of HCl make it challenging to measure. This instrument can overcome many of these challenges, enabling reliable HCl measurements.
Marvin Glowania, Franz Rohrer, Hans-Peter Dorn, Andreas Hofzumahaus, Frank Holland, Astrid Kiendler-Scharr, Andreas Wahner, and Hendrik Fuchs
Atmos. Meas. Tech., 14, 4239–4253, https://doi.org/10.5194/amt-14-4239-2021, https://doi.org/10.5194/amt-14-4239-2021, 2021
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Three instruments that use different techniques to measure gaseous formaldehyde concentrations were compared in experiments in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich. The results demonstrated the need to correct the baseline in measurements by instruments that use the Hantzsch reaction or make use of cavity ring-down spectroscopy. After applying corrections, all three methods gave accurate and precise measurements within their specifications.
Attilio Naccarato, Antonella Tassone, Maria Martino, Sacha Moretti, Antonella Macagnano, Emiliano Zampetti, Paolo Papa, Joshua Avossa, Nicola Pirrone, Michelle Nerentorp, John Munthe, Ingvar Wängberg, Geoff W. Stupple, Carl P. J. Mitchell, Adam R. Martin, Alexandra Steffen, Diana Babi, Eric M. Prestbo, Francesca Sprovieri, and Frank Wania
Atmos. Meas. Tech., 14, 3657–3672, https://doi.org/10.5194/amt-14-3657-2021, https://doi.org/10.5194/amt-14-3657-2021, 2021
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Mercury monitoring in support of the Minamata Convention requires effective and reliable analytical tools. Passive sampling is a promising approach for creating a sustainable long-term network for atmospheric mercury with improved spatial resolution and global coverage. In this study the analytical performance of three passive air samplers (CNR-PAS, IVL-PAS, and MerPAS) was assessed over extended deployment periods and the accuracy of concentrations was judged by comparison with active sampling.
Mei Bai, José I. Velazco, Trevor W. Coates, Frances A. Phillips, Thomas K. Flesch, Julian Hill, David G. Mayer, Nigel W. Tomkins, Roger S. Hegarty, and Deli Chen
Atmos. Meas. Tech., 14, 3469–3479, https://doi.org/10.5194/amt-14-3469-2021, https://doi.org/10.5194/amt-14-3469-2021, 2021
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The development and validation of management practices to mitigate methane (CH4) emissions from livestock require accurate emission measurements. We compared the inverse dispersion modelling (IDM) and tracer-ratio techniques to measure CH4 emissions from cattle. Both measurements agreed well but were higher than IPCC estimates. We suggest that the IDM approach can provide an accurate method of estimating cattle emissions, and IPCC estimates may have larger uncertainties.
Yuan You, Ralf M. Staebler, Samar G. Moussa, James Beck, and Richard L. Mittermeier
Atmos. Meas. Tech., 14, 1879–1892, https://doi.org/10.5194/amt-14-1879-2021, https://doi.org/10.5194/amt-14-1879-2021, 2021
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Tailings ponds in the Alberta oil sands can be significant sources of methane, an important greenhouse gas. This paper describes a 1-month study conducted in 2017 to measure methane emissions from a pond using a variety of micrometeorological flux methods and demonstrates some advantages of these methods over flux chambers.
Christoph Häni, Marcel Bühler, Albrecht Neftel, Christof Ammann, and Thomas Kupper
Atmos. Meas. Tech., 14, 1733–1741, https://doi.org/10.5194/amt-14-1733-2021, https://doi.org/10.5194/amt-14-1733-2021, 2021
Seth Kutikoff, Xiaomao Lin, Steven R. Evett, Prasanna Gowda, David Brauer, Jerry Moorhead, Gary Marek, Paul Colaizzi, Robert Aiken, Liukang Xu, and Clenton Owensby
Atmos. Meas. Tech., 14, 1253–1266, https://doi.org/10.5194/amt-14-1253-2021, https://doi.org/10.5194/amt-14-1253-2021, 2021
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Fast-response infrared gas sensors have been used over 3 decades for long-term monitoring of water vapor fluxes. As optically improved infrared gas sensors are newly employed, we evaluated the performance of water vapor density and water vapor flux from three generations of infrared gas sensors in Bushland, Texas, USA. From our experiments, fluxes from the old sensors were best representative of evapotranspiration based on a world-class lysimeter reference measurement.
Yuan You, Samar G. Moussa, Lucas Zhang, Long Fu, James Beck, and Ralf M. Staebler
Atmos. Meas. Tech., 14, 945–959, https://doi.org/10.5194/amt-14-945-2021, https://doi.org/10.5194/amt-14-945-2021, 2021
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Tailings ponds in the Alberta oil sands represent an insufficiently characterized source of fugitive emissions of pollutants to the atmosphere. In this study, a novel approach of using a Fourier transform infrared spectrometer along with measurements of atmospheric turbulence is shown to present a practical, non-intrusive method of quantifying emission rates for ammonia, alkanes, and methane. Results from a 1-month field study are presented and discussed.
Ravi Sahu, Ayush Nagal, Kuldeep Kumar Dixit, Harshavardhan Unnibhavi, Srikanth Mantravadi, Srijith Nair, Yogesh Simmhan, Brijesh Mishra, Rajesh Zele, Ronak Sutaria, Vidyanand Motiram Motghare, Purushottam Kar, and Sachchida Nand Tripathi
Atmos. Meas. Tech., 14, 37–52, https://doi.org/10.5194/amt-14-37-2021, https://doi.org/10.5194/amt-14-37-2021, 2021
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A unique feature of our low-cost sensor deployment is a swap-out experiment wherein four of the six sensors were relocated to different sites in the two phases. The swap-out experiment is crucial in investigating the efficacy of calibration models when applied to weather and air quality conditions vastly different from those present during calibration. We developed a novel local calibration algorithm based on metric learning that offers stable and accurate calibration performance.
Michal Vojtisek-Lom, Alessandro A. Zardini, Martin Pechout, Lubos Dittrich, Fausto Forni, François Montigny, Massimo Carriero, Barouch Giechaskiel, and Giorgio Martini
Atmos. Meas. Tech., 13, 5827–5843, https://doi.org/10.5194/amt-13-5827-2020, https://doi.org/10.5194/amt-13-5827-2020, 2020
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The feasibility of monitoring on-road emissions from small motorcycles with two highly compact portable emissions monitoring systems was evaluated on three motorcycles, with positive results. Mass emissions measured on the road were consistent among repeated runs, with differences between laboratory and on-road tests much larger than those between portable and laboratory systems, which were, on the average, within units of percent over standard test cycles.
Xiaoyu Sun, Minzheng Duan, Yang Gao, Rui Han, Denghui Ji, Wenxing Zhang, Nong Chen, Xiangao Xia, Hailei Liu, and Yanfeng Huo
Atmos. Meas. Tech., 13, 3595–3607, https://doi.org/10.5194/amt-13-3595-2020, https://doi.org/10.5194/amt-13-3595-2020, 2020
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The accurate measurement of greenhouse gases and their vertical distribution in the atmosphere is significant to the study of climate change and satellite remote sensing. Carbon dioxide and methane between 0.6 and 7 km were measured by the aircraft King Air 350ER in Jiansanjiang, northeast China, on 7–11 August 2018. The profiles show strong variation with the altitude and time, so the vertical structure of gases should be taken into account in the current satellite retrieval algorithm.
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Short summary
In this work we present experimental field results of a lower-cost eddy covariance (LC-EC) system, which can measure the ecosystem exchange of carbon dioxide and water vapour with the atmosphere. During three field campaigns on a grassland and agroforestry grassland, we compared the LC-EC with a conventional eddy covariance (CON-EC) system. Our results show that LC-EC has the potential to measure EC fluxes at only approximately 25 % of the cost of a CON-EC system.
In this work we present experimental field results of a lower-cost eddy covariance (LC-EC)...
