Articles | Volume 18, issue 13
https://doi.org/10.5194/acp-18-10007-2018
© 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/acp-18-10007-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
13 Jul 2018
Research article |
| 13 Jul 2018
| 13 Jul 2018
Upscaling surface energy fluxes over the North Slope of Alaska using airborne eddy-covariance measurements and environmental response functions
Andrei Serafimovich
CORRESPONDING AUTHOR
Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
Stefan Metzger
National Ecological Observatory Network, Fundamental Instrument Unit, 1685 38th Street, Boulder, CO 80301, USA
University of Wisconsin-Madison, Dept. of Atmospheric and Oceanic Sciences, 1225 West Dayton Street, Madison, WI 53706, USA
Jörg Hartmann
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), Am Handelshafen 12, 27570 Bremerhaven, Germany
Katrin Kohnert
Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
Donatella Zona
Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
Department of Biology, San Diego State University, 5500 Campanile Drive San Diego, CA 92182, USA
Torsten Sachs
Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany
Institute of Flight Guidance, TU Braunschweig, Hermann-Blenk-Str. 27, 38108 Braunschweig, Germany
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Samuel J. Cliff, Will Drysdale, James D. Lee, Carole Helfter, Eiko Nemitz, Stefan Metzger, and Janet F. Barlow
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Luke D. Schiferl, Jennifer D. Watts, Erik J. L. Larson, Kyle A. Arndt, Sébastien C. Biraud, Eugénie S. Euskirchen, Jordan P. Goodrich, John M. Henderson, Aram Kalhori, Kathryn McKain, Marikate E. Mountain, J. William Munger, Walter C. Oechel, Colm Sweeney, Yonghong Yi, Donatella Zona, and Róisín Commane
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Lutz Beckebanze, Benjamin R. K. Runkle, Josefine Walz, Christian Wille, David Holl, Manuel Helbig, Julia Boike, Torsten Sachs, and Lars Kutzbach
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Will S. Drysdale, Adam R. Vaughan, Freya A. Squires, Sam J. Cliff, Stefan Metzger, David Durden, Natchaya Pingintha-Durden, Carole Helfter, Eiko Nemitz, C. Sue B. Grimmond, Janet Barlow, Sean Beevers, Gregor Stewart, David Dajnak, Ruth M. Purvis, and James D. Lee
Atmos. Chem. Phys., 22, 9413–9433, https://doi.org/10.5194/acp-22-9413-2022, https://doi.org/10.5194/acp-22-9413-2022, 2022
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Jessica Plein, Rulon W. Clark, Kyle A. Arndt, Walter C. Oechel, Douglas Stow, and Donatella Zona
Biogeosciences, 19, 2779–2794, https://doi.org/10.5194/bg-19-2779-2022, https://doi.org/10.5194/bg-19-2779-2022, 2022
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Tundra vegetation and the carbon balance of Arctic ecosystems can be substantially impacted by herbivory. We tested how herbivory by brown lemmings in individual enclosure plots have impacted carbon exchange of tundra ecosystems via altering carbon dioxide (CO2) and methane (CH4) fluxes. Lemmings significantly decreased net CO2 uptake while not affecting CH4 emissions. There was no significant difference in the subsequent growing season due to recovery of the vegetation.
Janosch Michaelis, Amelie U. Schmitt, Christof Lüpkes, Jörg Hartmann, Gerit Birnbaum, and Timo Vihma
Earth Syst. Sci. Data, 14, 1621–1637, https://doi.org/10.5194/essd-14-1621-2022, https://doi.org/10.5194/essd-14-1621-2022, 2022
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Hanna K. Lappalainen, Tuukka Petäjä, Timo Vihma, Jouni Räisänen, Alexander Baklanov, Sergey Chalov, Igor Esau, Ekaterina Ezhova, Matti Leppäranta, Dmitry Pozdnyakov, Jukka Pumpanen, Meinrat O. Andreae, Mikhail Arshinov, Eija Asmi, Jianhui Bai, Igor Bashmachnikov, Boris Belan, Federico Bianchi, Boris Biskaborn, Michael Boy, Jaana Bäck, Bin Cheng, Natalia Chubarova, Jonathan Duplissy, Egor Dyukarev, Konstantinos Eleftheriadis, Martin Forsius, Martin Heimann, Sirkku Juhola, Vladimir Konovalov, Igor Konovalov, Pavel Konstantinov, Kajar Köster, Elena Lapshina, Anna Lintunen, Alexander Mahura, Risto Makkonen, Svetlana Malkhazova, Ivan Mammarella, Stefano Mammola, Stephany Buenrostro Mazon, Outi Meinander, Eugene Mikhailov, Victoria Miles, Stanislav Myslenkov, Dmitry Orlov, Jean-Daniel Paris, Roberta Pirazzini, Olga Popovicheva, Jouni Pulliainen, Kimmo Rautiainen, Torsten Sachs, Vladimir Shevchenko, Andrey Skorokhod, Andreas Stohl, Elli Suhonen, Erik S. Thomson, Marina Tsidilina, Veli-Pekka Tynkkynen, Petteri Uotila, Aki Virkkula, Nadezhda Voropay, Tobias Wolf, Sayaka Yasunaka, Jiahua Zhang, Yubao Qiu, Aijun Ding, Huadong Guo, Valery Bondur, Nikolay Kasimov, Sergej Zilitinkevich, Veli-Matti Kerminen, and Markku Kulmala
Atmos. Chem. Phys., 22, 4413–4469, https://doi.org/10.5194/acp-22-4413-2022, https://doi.org/10.5194/acp-22-4413-2022, 2022
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We summarize results during the last 5 years in the northern Eurasian region, especially from Russia, and introduce recent observations of the air quality in the urban environments in China. Although the scientific knowledge in these regions has increased, there are still gaps in our understanding of large-scale climate–Earth surface interactions and feedbacks. This arises from limitations in research infrastructures and integrative data analyses, hindering a comprehensive system analysis.
Elodie Salmon, Fabrice Jégou, Bertrand Guenet, Line Jourdain, Chunjing Qiu, Vladislav Bastrikov, Christophe Guimbaud, Dan Zhu, Philippe Ciais, Philippe Peylin, Sébastien Gogo, Fatima Laggoun-Défarge, Mika Aurela, M. Syndonia Bret-Harte, Jiquan Chen, Bogdan H. Chojnicki, Housen Chu, Colin W. Edgar, Eugenie S. Euskirchen, Lawrence B. Flanagan, Krzysztof Fortuniak, David Holl, Janina Klatt, Olaf Kolle, Natalia Kowalska, Lars Kutzbach, Annalea Lohila, Lutz Merbold, Włodzimierz Pawlak, Torsten Sachs, and Klaudia Ziemblińska
Geosci. Model Dev., 15, 2813–2838, https://doi.org/10.5194/gmd-15-2813-2022, https://doi.org/10.5194/gmd-15-2813-2022, 2022
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A methane model that features methane production and transport by plants, the ebullition process and diffusion in soil, oxidation to CO2, and CH4 fluxes to the atmosphere has been embedded in the ORCHIDEE-PEAT land surface model, which includes an explicit representation of northern peatlands. This model, ORCHIDEE-PCH4, was calibrated and evaluated on 14 peatland sites. Results show that the model is sensitive to temperature and substrate availability over the top 75 cm of soil depth.
Anna A. Shestakova, Dmitry G. Chechin, Christof Lüpkes, Jörg Hartmann, and Marion Maturilli
Atmos. Chem. Phys., 22, 1529–1548, https://doi.org/10.5194/acp-22-1529-2022, https://doi.org/10.5194/acp-22-1529-2022, 2022
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This article presents a comprehensive analysis of the easterly orographic wind episode which occurred over Svalbard on 30–31 May 2017. This wind caused a significant temperature rise on the lee side of the mountains and greatly intensified the snowmelt. This episode was investigated on the basis of measurements collected during the ACLOUD/PASCAL field campaigns with the help of numerical modeling.
Anna-Maria Virkkala, Susan M. Natali, Brendan M. Rogers, Jennifer D. Watts, Kathleen Savage, Sara June Connon, Marguerite Mauritz, Edward A. G. Schuur, Darcy Peter, Christina Minions, Julia Nojeim, Roisin Commane, Craig A. Emmerton, Mathias Goeckede, Manuel Helbig, David Holl, Hiroki Iwata, Hideki Kobayashi, Pasi Kolari, Efrén López-Blanco, Maija E. Marushchak, Mikhail Mastepanov, Lutz Merbold, Frans-Jan W. Parmentier, Matthias Peichl, Torsten Sachs, Oliver Sonnentag, Masahito Ueyama, Carolina Voigt, Mika Aurela, Julia Boike, Gerardo Celis, Namyi Chae, Torben R. Christensen, M. Syndonia Bret-Harte, Sigrid Dengel, Han Dolman, Colin W. Edgar, Bo Elberling, Eugenie Euskirchen, Achim Grelle, Juha Hatakka, Elyn Humphreys, Järvi Järveoja, Ayumi Kotani, Lars Kutzbach, Tuomas Laurila, Annalea Lohila, Ivan Mammarella, Yojiro Matsuura, Gesa Meyer, Mats B. Nilsson, Steven F. Oberbauer, Sang-Jong Park, Roman Petrov, Anatoly S. Prokushkin, Christopher Schulze, Vincent L. St. Louis, Eeva-Stiina Tuittila, Juha-Pekka Tuovinen, William Quinton, Andrej Varlagin, Donatella Zona, and Viacheslav I. Zyryanov
Earth Syst. Sci. Data, 14, 179–208, https://doi.org/10.5194/essd-14-179-2022, https://doi.org/10.5194/essd-14-179-2022, 2022
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The effects of climate warming on carbon cycling across the Arctic–boreal zone (ABZ) remain poorly understood due to the relatively limited distribution of ABZ flux sites. Fortunately, this flux network is constantly increasing, but new measurements are published in various platforms, making it challenging to understand the ABZ carbon cycle as a whole. Here, we compiled a new database of Arctic–boreal CO2 fluxes to help facilitate large-scale assessments of the ABZ carbon cycle.
Stefan Metzger, David Durden, Sreenath Paleri, Matthias Sühring, Brian J. Butterworth, Christopher Florian, Matthias Mauder, David M. Plummer, Luise Wanner, Ke Xu, and Ankur R. Desai
Atmos. Meas. Tech., 14, 6929–6954, https://doi.org/10.5194/amt-14-6929-2021, https://doi.org/10.5194/amt-14-6929-2021, 2021
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The key points are the following. (i) Integrative observing system design can multiply the information gain of surface–atmosphere field measurements. (ii) Catalyzing numerical simulations and first-principles machine learning open up observing system simulation experiments to novel applications. (iii) Use cases include natural climate solutions, emission inventory validation, urban air quality, and industry leak detection.
Adam R. Vaughan, James D. Lee, Stefan Metzger, David Durden, Alastair C. Lewis, Marvin D. Shaw, Will S. Drysdale, Ruth M. Purvis, Brian Davison, and C. Nicholas Hewitt
Atmos. Chem. Phys., 21, 15283–15298, https://doi.org/10.5194/acp-21-15283-2021, https://doi.org/10.5194/acp-21-15283-2021, 2021
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Validating emissions estimates of atmospheric pollutants is a vital pathway towards reducing urban concentrations of air pollution and ensuring effective legislative controls are implemented. The work presented here highlights a strategy capable of quantifying and spatially disaggregating NOx emissions over challenging urban terrain. This work shows great scope as a tool for emission inventory validation and independent generation of high-resolution surface emissions on a city-wide scale.
Kyle B. Delwiche, Sara Helen Knox, Avni Malhotra, Etienne Fluet-Chouinard, Gavin McNicol, Sarah Feron, Zutao Ouyang, Dario Papale, Carlo Trotta, Eleonora Canfora, You-Wei Cheah, Danielle Christianson, Ma. Carmelita R. Alberto, Pavel Alekseychik, Mika Aurela, Dennis Baldocchi, Sheel Bansal, David P. Billesbach, Gil Bohrer, Rosvel Bracho, Nina Buchmann, David I. Campbell, Gerardo Celis, Jiquan Chen, Weinan Chen, Housen Chu, Higo J. Dalmagro, Sigrid Dengel, Ankur R. Desai, Matteo Detto, Han Dolman, Elke Eichelmann, Eugenie Euskirchen, Daniela Famulari, Kathrin Fuchs, Mathias Goeckede, Sébastien Gogo, Mangaliso J. Gondwe, Jordan P. Goodrich, Pia Gottschalk, Scott L. Graham, Martin Heimann, Manuel Helbig, Carole Helfter, Kyle S. Hemes, Takashi Hirano, David Hollinger, Lukas Hörtnagl, Hiroki Iwata, Adrien Jacotot, Gerald Jurasinski, Minseok Kang, Kuno Kasak, John King, Janina Klatt, Franziska Koebsch, Ken W. Krauss, Derrick Y. F. Lai, Annalea Lohila, Ivan Mammarella, Luca Belelli Marchesini, Giovanni Manca, Jaclyn Hatala Matthes, Trofim Maximov, Lutz Merbold, Bhaskar Mitra, Timothy H. Morin, Eiko Nemitz, Mats B. Nilsson, Shuli Niu, Walter C. Oechel, Patricia Y. Oikawa, Keisuke Ono, Matthias Peichl, Olli Peltola, Michele L. Reba, Andrew D. Richardson, William Riley, Benjamin R. K. Runkle, Youngryel Ryu, Torsten Sachs, Ayaka Sakabe, Camilo Rey Sanchez, Edward A. Schuur, Karina V. R. Schäfer, Oliver Sonnentag, Jed P. Sparks, Ellen Stuart-Haëntjens, Cove Sturtevant, Ryan C. Sullivan, Daphne J. Szutu, Jonathan E. Thom, Margaret S. Torn, Eeva-Stiina Tuittila, Jessica Turner, Masahito Ueyama, Alex C. Valach, Rodrigo Vargas, Andrej Varlagin, Alma Vazquez-Lule, Joseph G. Verfaillie, Timo Vesala, George L. Vourlitis, Eric J. Ward, Christian Wille, Georg Wohlfahrt, Guan Xhuan Wong, Zhen Zhang, Donatella Zona, Lisamarie Windham-Myers, Benjamin Poulter, and Robert B. Jackson
Earth Syst. Sci. Data, 13, 3607–3689, https://doi.org/10.5194/essd-13-3607-2021, https://doi.org/10.5194/essd-13-3607-2021, 2021
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Methane is an important greenhouse gas, yet we lack knowledge about its global emissions and drivers. We present FLUXNET-CH4, a new global collection of methane measurements and a critical resource for the research community. We use FLUXNET-CH4 data to quantify the seasonality of methane emissions from freshwater wetlands, finding that methane seasonality varies strongly with latitude. Our new database and analysis will improve wetland model accuracy and inform greenhouse gas budgets.
Leah Birch, Christopher R. Schwalm, Sue Natali, Danica Lombardozzi, Gretchen Keppel-Aleks, Jennifer Watts, Xin Lin, Donatella Zona, Walter Oechel, Torsten Sachs, Thomas Andrew Black, and Brendan M. Rogers
Geosci. Model Dev., 14, 3361–3382, https://doi.org/10.5194/gmd-14-3361-2021, https://doi.org/10.5194/gmd-14-3361-2021, 2021
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The high-latitude landscape or Arctic–boreal zone has been warming rapidly, impacting the carbon balance both regionally and globally. Given the possible global effects of climate change, it is important to have accurate climate model simulations. We assess the simulation of the Arctic–boreal carbon cycle in the Community Land Model (CLM 5.0). We find biases in both the timing and magnitude photosynthesis. We then use observational data to improve the simulation of the carbon cycle.
David C. Loades, Mingxi Yang, Thomas G. Bell, Adam R. Vaughan, Ryan J. Pound, Stefan Metzger, James D. Lee, and Lucy J. Carpenter
Atmos. Meas. Tech., 13, 6915–6931, https://doi.org/10.5194/amt-13-6915-2020, https://doi.org/10.5194/amt-13-6915-2020, 2020
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The loss of ozone to the sea surface was measured from the south coast of the UK and was found to be more rapid than previous observations over the open ocean. This is likely a consequence of different chemistry and biology in coastal environments. Strong winds appeared to speed up the loss of ozone. A better understanding of what influences ozone loss over the sea will lead to better model estimates of total ozone in the troposphere.
W. Joe F. Acton, Zhonghui Huang, Brian Davison, Will S. Drysdale, Pingqing Fu, Michael Hollaway, Ben Langford, James Lee, Yanhui Liu, Stefan Metzger, Neil Mullinger, Eiko Nemitz, Claire E. Reeves, Freya A. Squires, Adam R. Vaughan, Xinming Wang, Zhaoyi Wang, Oliver Wild, Qiang Zhang, Yanli Zhang, and C. Nicholas Hewitt
Atmos. Chem. Phys., 20, 15101–15125, https://doi.org/10.5194/acp-20-15101-2020, https://doi.org/10.5194/acp-20-15101-2020, 2020
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Air quality in Beijing is of concern to both policy makers and the general public. In order to address concerns about air quality it is vital that the sources of atmospheric pollutants are understood. This work presents the first top-down measurement of volatile organic compound (VOC) emissions in Beijing. These measurements are used to evaluate the emissions inventory and assess the impact of VOC emission from the city centre on atmospheric chemistry.
Yonghong Yi, John S. Kimball, Jennifer D. Watts, Susan M. Natali, Donatella Zona, Junjie Liu, Masahito Ueyama, Hideki Kobayashi, Walter Oechel, and Charles E. Miller
Biogeosciences, 17, 5861–5882, https://doi.org/10.5194/bg-17-5861-2020, https://doi.org/10.5194/bg-17-5861-2020, 2020
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We developed a 1 km satellite-data-driven permafrost carbon model to evaluate soil respiration sensitivity to recent snow cover changes in Alaska. Results show earlier snowmelt enhances growing-season soil respiration and reduces annual carbon uptake, while early cold-season soil respiration is linked to the number of snow-free days after the land surface freezes. Our results also show nonnegligible influences of subgrid variability in surface conditions on model-simulated CO2 seasonal cycles.
Felix Nieberding, Christian Wille, Gerardo Fratini, Magnus O. Asmussen, Yuyang Wang, Yaoming Ma, and Torsten Sachs
Earth Syst. Sci. Data, 12, 2705–2724, https://doi.org/10.5194/essd-12-2705-2020, https://doi.org/10.5194/essd-12-2705-2020, 2020
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We present the first long-term eddy covariance CO2 and H2O flux measurements from the large but underrepresented alpine steppe ecosystem on the central Tibetan Plateau. We applied careful corrections and rigorous quality filtering and analyzed the turbulent flow regime to provide meaningful fluxes. This comprehensive data set allows potential users to put the gas flux dynamics into context with ecosystem properties and potential flux drivers and allows for comparisons with other data sets.
Freya A. Squires, Eiko Nemitz, Ben Langford, Oliver Wild, Will S. Drysdale, W. Joe F. Acton, Pingqing Fu, C. Sue B. Grimmond, Jacqueline F. Hamilton, C. Nicholas Hewitt, Michael Hollaway, Simone Kotthaus, James Lee, Stefan Metzger, Natchaya Pingintha-Durden, Marvin Shaw, Adam R. Vaughan, Xinming Wang, Ruili Wu, Qiang Zhang, and Yanli Zhang
Atmos. Chem. Phys., 20, 8737–8761, https://doi.org/10.5194/acp-20-8737-2020, https://doi.org/10.5194/acp-20-8737-2020, 2020
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Significant air quality problems exist in megacities like Beijing, China. To manage air pollution, legislators need a clear understanding of pollutant emissions. However, emissions inventories have large uncertainties, and reliable field measurements of pollutant emissions are required to constrain them. This work presents the first measurements of traffic-dominated emissions in Beijing which suggest that inventories overestimate these emissions in the region during both winter and summer.
Tuukka Petäjä, Ella-Maria Duplissy, Ksenia Tabakova, Julia Schmale, Barbara Altstädter, Gerard Ancellet, Mikhail Arshinov, Yurii Balin, Urs Baltensperger, Jens Bange, Alison Beamish, Boris Belan, Antoine Berchet, Rossana Bossi, Warren R. L. Cairns, Ralf Ebinghaus, Imad El Haddad, Beatriz Ferreira-Araujo, Anna Franck, Lin Huang, Antti Hyvärinen, Angelika Humbert, Athina-Cerise Kalogridis, Pavel Konstantinov, Astrid Lampert, Matthew MacLeod, Olivier Magand, Alexander Mahura, Louis Marelle, Vladimir Masloboev, Dmitri Moisseev, Vaios Moschos, Niklas Neckel, Tatsuo Onishi, Stefan Osterwalder, Aino Ovaska, Pauli Paasonen, Mikhail Panchenko, Fidel Pankratov, Jakob B. Pernov, Andreas Platis, Olga Popovicheva, Jean-Christophe Raut, Aurélie Riandet, Torsten Sachs, Rosamaria Salvatori, Roberto Salzano, Ludwig Schröder, Martin Schön, Vladimir Shevchenko, Henrik Skov, Jeroen E. Sonke, Andrea Spolaor, Vasileios K. Stathopoulos, Mikko Strahlendorff, Jennie L. Thomas, Vito Vitale, Sterios Vratolis, Carlo Barbante, Sabine Chabrillat, Aurélien Dommergue, Konstantinos Eleftheriadis, Jyri Heilimo, Kathy S. Law, Andreas Massling, Steffen M. Noe, Jean-Daniel Paris, André S. H. Prévôt, Ilona Riipinen, Birgit Wehner, Zhiyong Xie, and Hanna K. Lappalainen
Atmos. Chem. Phys., 20, 8551–8592, https://doi.org/10.5194/acp-20-8551-2020, https://doi.org/10.5194/acp-20-8551-2020, 2020
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The role of polar regions is increasing in terms of megatrends such as globalization, new transport routes, demography, and the use of natural resources with consequent effects on regional and transported pollutant concentrations. Here we summarize initial results from our integrative project exploring the Arctic environment and pollution to deliver data products, metrics, and indicators for stakeholders.
Astrid Lampert, Falk Pätzold, Magnus O. Asmussen, Lennart Lobitz, Thomas Krüger, Thomas Rausch, Torsten Sachs, Christian Wille, Denis Sotomayor Zakharov, Dominik Gaus, Stephan Bansmer, and Ellen Damm
Atmos. Meas. Tech., 13, 1937–1952, https://doi.org/10.5194/amt-13-1937-2020, https://doi.org/10.5194/amt-13-1937-2020, 2020
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Methane has high climate warming potential. Sources of methane can be distinguished by the isotopic composition. To investigate the origin of methane, an airborne sampling system has been developed that can take air samples worldwide and at various altitudes. The article shows the performance of the overall system, from taking samples to laboratory analyses. As known methane source, a rewetted peatland site, was studied, and the vertical distribution of the isotopic composition is investigated.
André Ehrlich, Manfred Wendisch, Christof Lüpkes, Matthias Buschmann, Heiko Bozem, Dmitri Chechin, Hans-Christian Clemen, Régis Dupuy, Olliver Eppers, Jörg Hartmann, Andreas Herber, Evelyn Jäkel, Emma Järvinen, Olivier Jourdan, Udo Kästner, Leif-Leonard Kliesch, Franziska Köllner, Mario Mech, Stephan Mertes, Roland Neuber, Elena Ruiz-Donoso, Martin Schnaiter, Johannes Schneider, Johannes Stapf, and Marco Zanatta
Earth Syst. Sci. Data, 11, 1853–1881, https://doi.org/10.5194/essd-11-1853-2019, https://doi.org/10.5194/essd-11-1853-2019, 2019
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During the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign, two research aircraft (Polar 5 and 6) jointly performed 22 research flights over the transition zone between open ocean and closed sea ice. The data set combines remote sensing and in situ measurement of cloud, aerosol, and trace gas properties, as well as turbulent and radiative fluxes, which will be used to study Arctic boundary layer and mid-level clouds and their role in Arctic amplification.
Olli Peltola, Timo Vesala, Yao Gao, Olle Räty, Pavel Alekseychik, Mika Aurela, Bogdan Chojnicki, Ankur R. Desai, Albertus J. Dolman, Eugenie S. Euskirchen, Thomas Friborg, Mathias Göckede, Manuel Helbig, Elyn Humphreys, Robert B. Jackson, Georg Jocher, Fortunat Joos, Janina Klatt, Sara H. Knox, Natalia Kowalska, Lars Kutzbach, Sebastian Lienert, Annalea Lohila, Ivan Mammarella, Daniel F. Nadeau, Mats B. Nilsson, Walter C. Oechel, Matthias Peichl, Thomas Pypker, William Quinton, Janne Rinne, Torsten Sachs, Mateusz Samson, Hans Peter Schmid, Oliver Sonnentag, Christian Wille, Donatella Zona, and Tuula Aalto
Earth Syst. Sci. Data, 11, 1263–1289, https://doi.org/10.5194/essd-11-1263-2019, https://doi.org/10.5194/essd-11-1263-2019, 2019
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Here we develop a monthly gridded dataset of northern (> 45 N) wetland methane (CH4) emissions. The data product is derived using a random forest machine-learning technique and eddy covariance CH4 fluxes from 25 wetland sites. Annual CH4 emissions from these wetlands calculated from the derived data product are comparable to prior studies focusing on these areas. This product is an independent estimate of northern wetland CH4 emissions and hence could be used, e.g. for process model evaluation.
Andrew M. Cunliffe, George Tanski, Boris Radosavljevic, William F. Palmer, Torsten Sachs, Hugues Lantuit, Jeffrey T. Kerby, and Isla H. Myers-Smith
The Cryosphere, 13, 1513–1528, https://doi.org/10.5194/tc-13-1513-2019, https://doi.org/10.5194/tc-13-1513-2019, 2019
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Episodic changes of permafrost coastlines are poorly understood in the Arctic. By using drones, satellite images, and historic photos we surveyed a permafrost coastline on Qikiqtaruk – Herschel Island. We observed short-term coastline retreat of 14.5 m per year (2016–2017), exceeding long-term average rates of 2.2 m per year (1952–2017). Our study highlights the value of these tools to assess understudied episodic changes of eroding permafrost coastlines in the context of a warming Arctic.
Franziska Koebsch, Matthias Winkel, Susanne Liebner, Bo Liu, Julia Westphal, Iris Schmiedinger, Alejandro Spitzy, Matthias Gehre, Gerald Jurasinski, Stefan Köhler, Viktoria Unger, Marian Koch, Torsten Sachs, and Michael E. Böttcher
Biogeosciences, 16, 1937–1953, https://doi.org/10.5194/bg-16-1937-2019, https://doi.org/10.5194/bg-16-1937-2019, 2019
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In natural coastal wetlands, high supplies of marine sulfate suppress methane production. We found these natural methane suppression mechanisms to be suspended by humane interference in a brackish wetland. Here, diking and freshwater rewetting had caused an efficient depletion of the sulfate reservoir and opened up favorable conditions for an intensive methane production. Our results demonstrate how human disturbance can turn coastal wetlands into distinct sources of the greenhouse gas methane.
David Holl, Christian Wille, Torsten Sachs, Peter Schreiber, Benjamin R. K. Runkle, Lutz Beckebanze, Moritz Langer, Julia Boike, Eva-Maria Pfeiffer, Irina Fedorova, Dimitry Y. Bolshianov, Mikhail N. Grigoriev, and Lars Kutzbach
Earth Syst. Sci. Data, 11, 221–240, https://doi.org/10.5194/essd-11-221-2019, https://doi.org/10.5194/essd-11-221-2019, 2019
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We present a multi-annual time series of land–atmosphere carbon dioxide fluxes measured in situ with the eddy covariance technique in the Siberian Arctic. In arctic permafrost regions, climate–carbon feedbacks are amplified. Therefore, increased efforts to better represent these regions in global climate models have been made in recent years. Up to now, the available database of in situ measurements from the Arctic was biased towards Alaska and records from the Eurasian Arctic were scarce.
Xi Wen, Viktoria Unger, Gerald Jurasinski, Franziska Koebsch, Fabian Horn, Gregor Rehder, Torsten Sachs, Dominik Zak, Gunnar Lischeid, Klaus-Holger Knorr, Michael E. Böttcher, Matthias Winkel, Paul L. E. Bodelier, and Susanne Liebner
Biogeosciences, 15, 6519–6536, https://doi.org/10.5194/bg-15-6519-2018, https://doi.org/10.5194/bg-15-6519-2018, 2018
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Rewetting drained peatlands may lead to prolonged emission of the greenhouse gas methane, but the underlying factors are not well described. In this study, we found two rewetted fens with known high methane fluxes had a high ratio of microbial methane producers to methane consumers and a low abundance of methane consumers compared to pristine wetlands. We therefore suggest abundances of methane-cycling microbes as potential indicators for prolonged high methane emissions in rewetted peatlands.
Sophia Walther, Luis Guanter, Birgit Heim, Martin Jung, Gregory Duveiller, Aleksandra Wolanin, and Torsten Sachs
Biogeosciences, 15, 6221–6256, https://doi.org/10.5194/bg-15-6221-2018, https://doi.org/10.5194/bg-15-6221-2018, 2018
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We explored the timing of the peak of the short annual growing season in tundra ecosystems as indicated by an extensive suite of satellite indicators of vegetation productivity. Delayed peak greenness compared to peak photosynthesis is consistently found across years and land-cover classes. Plants also experience growth after optimal conditions for assimilation regarding light and temperature have passed. Our results have implications for the modelling of the circumpolar carbon balance.
Jörg Hartmann, Martin Gehrmann, Katrin Kohnert, Stefan Metzger, and Torsten Sachs
Atmos. Meas. Tech., 11, 4567–4581, https://doi.org/10.5194/amt-11-4567-2018, https://doi.org/10.5194/amt-11-4567-2018, 2018
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We present new in-flight calibration procedures for airborne turbulence measurements that exploit suitable regular flight legs without the need for dedicated calibration patterns. Furthermore we estimate the accuracy of the airborne wind measurement and of the turbulent fluxes of the traces gases methane and carbon dioxide.
Astrid Lampert, Jörg Hartmann, Falk Pätzold, Lennart Lobitz, Peter Hecker, Katrin Kohnert, Eric Larmanou, Andrei Serafimovich, and Torsten Sachs
Atmos. Meas. Tech., 11, 2523–2536, https://doi.org/10.5194/amt-11-2523-2018, https://doi.org/10.5194/amt-11-2523-2018, 2018
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We compared two different fast-response humidity sensors simultaneously on different airborne platforms. One is a particular, well-establed Lyman-alpha hygrometer that has been used for decades as the standard for fast airborne humidity measurements. However, it is not available any more. The other one is a hygrometer based on the absorption of infrared radiation, from LI-COR. For an environment of low vibrations, the LI-COR sensor is suitable for fast airborne water vapour measurements.
Chunjing Qiu, Dan Zhu, Philippe Ciais, Bertrand Guenet, Gerhard Krinner, Shushi Peng, Mika Aurela, Christian Bernhofer, Christian Brümmer, Syndonia Bret-Harte, Housen Chu, Jiquan Chen, Ankur R. Desai, Jiří Dušek, Eugénie S. Euskirchen, Krzysztof Fortuniak, Lawrence B. Flanagan, Thomas Friborg, Mateusz Grygoruk, Sébastien Gogo, Thomas Grünwald, Birger U. Hansen, David Holl, Elyn Humphreys, Miriam Hurkuck, Gerard Kiely, Janina Klatt, Lars Kutzbach, Chloé Largeron, Fatima Laggoun-Défarge, Magnus Lund, Peter M. Lafleur, Xuefei Li, Ivan Mammarella, Lutz Merbold, Mats B. Nilsson, Janusz Olejnik, Mikaell Ottosson-Löfvenius, Walter Oechel, Frans-Jan W. Parmentier, Matthias Peichl, Norbert Pirk, Olli Peltola, Włodzimierz Pawlak, Daniel Rasse, Janne Rinne, Gaius Shaver, Hans Peter Schmid, Matteo Sottocornola, Rainer Steinbrecher, Torsten Sachs, Marek Urbaniak, Donatella Zona, and Klaudia Ziemblinska
Geosci. Model Dev., 11, 497–519, https://doi.org/10.5194/gmd-11-497-2018, https://doi.org/10.5194/gmd-11-497-2018, 2018
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Northern peatlands store large amount of soil carbon and are vulnerable to climate change. We implemented peatland hydrological and carbon accumulation processes into the ORCHIDEE land surface model. The model was evaluated against EC measurements from 30 northern peatland sites. The model generally well reproduced the spatial gradient and temporal variations in GPP and NEE at these sites. Water table depth was not well predicted but had only small influence on simulated NEE.
Yonghong Yi, John S. Kimball, Richard H. Chen, Mahta Moghaddam, Rolf H. Reichle, Umakant Mishra, Donatella Zona, and Walter C. Oechel
The Cryosphere, 12, 145–161, https://doi.org/10.5194/tc-12-145-2018, https://doi.org/10.5194/tc-12-145-2018, 2018
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An important feature of the Arctic is large spatial heterogeneity in active layer conditions. We developed a modeling framework integrating airborne longwave radar and satellite data to investigate active layer thickness (ALT) sensitivity to landscape heterogeneity in Alaska. We find uncertainty in spatial and vertical distribution of soil organic carbon is the largest factor affecting ALT accuracy. Advances in remote sensing of soil conditions will enable more accurate ALT predictions.
Miguel D. Mahecha, Fabian Gans, Sebastian Sippel, Jonathan F. Donges, Thomas Kaminski, Stefan Metzger, Mirco Migliavacca, Dario Papale, Anja Rammig, and Jakob Zscheischler
Biogeosciences, 14, 4255–4277, https://doi.org/10.5194/bg-14-4255-2017, https://doi.org/10.5194/bg-14-4255-2017, 2017
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We investigate the likelihood of ecological in situ networks to detect and monitor the impact of extreme events in the terrestrial biosphere.
Stefan Metzger, David Durden, Cove Sturtevant, Hongyan Luo, Natchaya Pingintha-Durden, Torsten Sachs, Andrei Serafimovich, Jörg Hartmann, Jiahong Li, Ke Xu, and Ankur R. Desai
Geosci. Model Dev., 10, 3189–3206, https://doi.org/10.5194/gmd-10-3189-2017, https://doi.org/10.5194/gmd-10-3189-2017, 2017
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We apply the
development and systems operationssoftware development model to create the eddy4R–Docker open-source, flexible, and modular eddy-covariance data processing environment. Test applications to aircraft and tower data, as well as a software cross validation demonstrate its efficiency and consistency. Key improvements in accessibility, extensibility, and reproducibility build the foundation for deploying complex scientific algorithms in an effective and scalable manner.
Sonja Kaiser, Mathias Göckede, Karel Castro-Morales, Christian Knoblauch, Altug Ekici, Thomas Kleinen, Sebastian Zubrzycki, Torsten Sachs, Christian Wille, and Christian Beer
Geosci. Model Dev., 10, 333–358, https://doi.org/10.5194/gmd-10-333-2017, https://doi.org/10.5194/gmd-10-333-2017, 2017
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A new consistent, process-based methane module that is integrated with permafrost processes is presented. It was developed within a global land surface scheme and evaluated at a polygonal tundra site in Samoylov, Russia. The calculated methane emissions show fair agreement with field data and capture detailed differences between the explicitly modelled gas transport processes and in the gas dynamics under varying soil water and temperature conditions during seasons and on different microsites.
Mathias Hoffmann, Maximilian Schulz-Hanke, Juana Garcia Alba, Nicole Jurisch, Ulrike Hagemann, Torsten Sachs, Michael Sommer, and Jürgen Augustin
Atmos. Meas. Tech., 10, 109–118, https://doi.org/10.5194/amt-10-109-2017, https://doi.org/10.5194/amt-10-109-2017, 2017
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Processes driving production and transport of CH4 in wetlands are complex. We present an algorithm to separate open-water automatic chamber CH4 fluxes into diffusion and ebullition. This helps to reveal dynamics, identify drivers and obtain reliable CH4 emissions. The algorithm is based on sudden concentration changes during single measurements. A variable filter is applied using a multiple of the interquartile range. The algorithm was verified for data of a rewetted former fen grassland site.
Xiyan Xu, William J. Riley, Charles D. Koven, Dave P. Billesbach, Rachel Y.-W. Chang, Róisín Commane, Eugénie S. Euskirchen, Sean Hartery, Yoshinobu Harazono, Hiroki Iwata, Kyle C. McDonald, Charles E. Miller, Walter C. Oechel, Benjamin Poulter, Naama Raz-Yaseef, Colm Sweeney, Margaret Torn, Steven C. Wofsy, Zhen Zhang, and Donatella Zona
Biogeosciences, 13, 5043–5056, https://doi.org/10.5194/bg-13-5043-2016, https://doi.org/10.5194/bg-13-5043-2016, 2016
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Wetlands are the largest global natural methane source. Peat-rich bogs and fens lying between 50°N and 70°N contribute 10–30% to this source. The predictive capability of the seasonal methane cycle can directly affect the estimation of global methane budget. We present multiscale methane seasonal emission by observations and modeling and find that the uncertainties in predicting the seasonal methane emissions are from the wetland extent, cold-season CH4 production and CH4 transport processes.
Daniela Franz, Franziska Koebsch, Eric Larmanou, Jürgen Augustin, and Torsten Sachs
Biogeosciences, 13, 3051–3070, https://doi.org/10.5194/bg-13-3051-2016, https://doi.org/10.5194/bg-13-3051-2016, 2016
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Based on the eddy covariance method we investigate the ecosystem–atmosphere exchange of CH4 and CO2 at a eutrophic shallow lake as a challenging ecosystem often evolving during peatland rewetting. Both open water and emergent vegetation are net emitters of CH4 and CO2, but with strikingly different release rates. Even after 9 years of rewetting the lake ecosystem exhibits a considerable carbon loss and global warming impact, the latter mainly driven by high CH4 emissions from the open waterbody.
Stefan Metzger, George Burba, Sean P. Burns, Peter D. Blanken, Jiahong Li, Hongyan Luo, and Rommel C. Zulueta
Atmos. Meas. Tech., 9, 1341–1359, https://doi.org/10.5194/amt-9-1341-2016, https://doi.org/10.5194/amt-9-1341-2016, 2016
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Enclosed infrared gas analyzers utilize a gas sampling system, which can substantially increase spectral corrections for eddy covariance applications. Here, we show that a requirements-based design can reduce high-frequency attenuation for H2O by ≈ 3/4, with the remaining flux correction not exceeding 3 %. The resulting gas sampling system can be used across a wide range of ecoclimates and site layouts, and enables more automated and comparable eddy covariance data processing across sites.
M. Hoffmann, M. Schulz-Hanke, J. Garcia Alba, N. Jurisch, U. Hagemann, T. Sachs, M. Sommer, and J. Augustin
Biogeosciences Discuss., https://doi.org/10.5194/bgd-12-12923-2015, https://doi.org/10.5194/bgd-12-12923-2015, 2015
Manuscript not accepted for further review
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Processes driving the production, transformation and transport of CH4 in wetlands are highly complex. Thus, serious challenges are constitutes in terms of process understanding, potential drivers and the calculation of reliable CH4 emission estimates. We present a simple calculation algorithm to separate CH4 fluxes measured with closed chambers into diffusion- and ebullition-derived components, which helps facilitating the identification of underlying dynamics and potential drivers.
T. De Groote, D. Zona, L. S. Broeckx, M. S. Verlinden, S. Luyssaert, V. Bellassen, N. Vuichard, R. Ceulemans, A. Gobin, and I. A. Janssens
Geosci. Model Dev., 8, 1461–1471, https://doi.org/10.5194/gmd-8-1461-2015, https://doi.org/10.5194/gmd-8-1461-2015, 2015
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This paper describes the modification of the widely used land surface model ORCHIDEE for stand-scale simulations of short rotation coppice (SRC) plantations. The modifications presented in this paper were evaluated using data from two Belgian poplar-based SRC sites, for which multiple measurements and meteorological data were available. The simulations show that the model predicts aboveground biomass production, ecosystem photosynthesis and ecosystem respiration well.
D. Zona, D. A. Lipson, J. H. Richards, G. K. Phoenix, A. K. Liljedahl, M. Ueyama, C. S. Sturtevant, and W. C. Oechel
Biogeosciences, 11, 5877–5888, https://doi.org/10.5194/bg-11-5877-2014, https://doi.org/10.5194/bg-11-5877-2014, 2014
A. Tetzlaff, C. Lüpkes, G. Birnbaum, J. Hartmann, T. Nygård, and T. Vihma
The Cryosphere, 8, 1757–1762, https://doi.org/10.5194/tc-8-1757-2014, https://doi.org/10.5194/tc-8-1757-2014, 2014
H. N. Mbufong, M. Lund, M. Aurela, T. R. Christensen, W. Eugster, T. Friborg, B. U. Hansen, E. R. Humphreys, M. Jackowicz-Korczynski, L. Kutzbach, P. M. Lafleur, W. C. Oechel, F. J. W. Parmentier, D. P. Rasse, A. V. Rocha, T. Sachs, M. K. van der Molen, and M. P. Tamstorf
Biogeosciences, 11, 4897–4912, https://doi.org/10.5194/bg-11-4897-2014, https://doi.org/10.5194/bg-11-4897-2014, 2014
M. Riederer, A. Serafimovich, and T. Foken
Atmos. Meas. Tech., 7, 1057–1064, https://doi.org/10.5194/amt-7-1057-2014, https://doi.org/10.5194/amt-7-1057-2014, 2014
J. D. Watts, J. S. Kimball, F. J. W. Parmentier, T. Sachs, J. Rinne, D. Zona, W. Oechel, T. Tagesson, M. Jackowicz-Korczyński, and M. Aurela
Biogeosciences, 11, 1961–1980, https://doi.org/10.5194/bg-11-1961-2014, https://doi.org/10.5194/bg-11-1961-2014, 2014
S. Dengel, D. Zona, T. Sachs, M. Aurela, M. Jammet, F. J. W. Parmentier, W. Oechel, and T. Vesala
Biogeosciences, 10, 8185–8200, https://doi.org/10.5194/bg-10-8185-2013, https://doi.org/10.5194/bg-10-8185-2013, 2013
S. Metzger, W. Junkermann, M. Mauder, K. Butterbach-Bahl, B. Trancón y Widemann, F. Neidl, K. Schäfer, S. Wieneke, X. H. Zheng, H. P. Schmid, and T. Foken
Biogeosciences, 10, 2193–2217, https://doi.org/10.5194/bg-10-2193-2013, https://doi.org/10.5194/bg-10-2193-2013, 2013
B. R. K. Runkle, T. Sachs, C. Wille, E.-M. Pfeiffer, and L. Kutzbach
Biogeosciences, 10, 1337–1349, https://doi.org/10.5194/bg-10-1337-2013, https://doi.org/10.5194/bg-10-1337-2013, 2013
T. Krings, K. Gerilowski, M. Buchwitz, J. Hartmann, T. Sachs, J. Erzinger, J. P. Burrows, and H. Bovensmann
Atmos. Meas. Tech., 6, 151–166, https://doi.org/10.5194/amt-6-151-2013, https://doi.org/10.5194/amt-6-151-2013, 2013
Related subject area
Subject: Dynamics | Research Activity: Field Measurements | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)
Identification and characterization of foehn events in Beijing and their impact on air-pollution episodes
Evidence of Tropospheric Uplift into the Stratosphere via the Tropical Western Pacific Cold Trap
Impact of Convectively Coupled Tropical Waves on the composition and vertical structure of the atmosphere above Cabo Verde in September 2021 during the CADDIWA campaign
Impact of boundary layer stability on urban park cooling effect intensity
Investigation of non-equilibrium turbulence decay in the atmospheric boundary layer using Doppler lidar measurements
Measurement report: The promotion of the low-level jet and thermal effects on the development of the deep convective boundary layer at the southern edge of the Taklimakan Desert
Estimating scalar turbulent fluxes with slow-response sensors in the stable atmospheric boundary layer
Overview: quasi-Lagrangian observations of Arctic air mass transformations – introduction and initial results of the HALO–(𝒜 𝒞)3 aircraft campaign
Contrasting extremely warm and long-lasting cold air anomalies in the North Atlantic sector of the Arctic during the HALO-(𝒜 𝒞)3 campaign
Air–sea interactions in stable atmospheric conditions: lessons from the desert semi-enclosed Gulf of Eilat (Aqaba)
An overview of the vertical structure of the atmospheric boundary layer in the central Arctic during MOSAiC
Evaluation of methods to determine the surface mixing layer height of the atmospheric boundary layer in the central Arctic during polar night and transition to polar day in cloudless and cloudy conditions
The role of a low-level jet for stirring the stable atmospheric surface layer in the Arctic
Detection of dilution due to turbulent mixing vs. precipitation scavenging effects on biomass burning aerosol concentrations using stable water isotope ratios during ORACLES
Modulation of the intraseasonal variability in early summer precipitation in eastern China by the Quasi-Biennial Oscillation and the Madden–Julian Oscillation
Thermodynamic and kinematic drivers of atmospheric boundary layer stability in the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC)
Occurrence frequency of subcritical Richardson numbers assessed by global high-resolution radiosonde and ERA5 reanalysis
The characteristics of atmospheric boundary layer height over the Arctic Ocean during MOSAiC
Turbulent structure of the Arctic boundary layer in early summer driven by stability, wind shear and cloud-top radiative cooling: ACLOUD airborne observations
Dependency of vertical velocity variance on meteorological conditions in the convective boundary layer
Triggering effects of large topography and boundary layer turbulence on convection over the Tibetan Plateau
A change in the relation between the Subtropical Indian Ocean Dipole and the South Atlantic Ocean Dipole indices in the past four decades
Characterising the dynamic movement of thunderstorms using very low- and low-frequency (VLF/LF) total lightning data over the Pearl River Delta region
Evolution of turbulent kinetic energy during the entire sandstorm process
Seasonal updraft speeds change cloud droplet number concentrations in low-level clouds over the western North Atlantic
The effect of ice supersaturation and thin cirrus on lapse rates in the upper troposphere
Momentum fluxes from airborne wind measurements in three cumulus cases over land
Orographically induced spontaneous imbalance within the jet causing a large-scale gravity wave event
Exploring the elevated water vapor signal associated with the free tropospheric biomass burning plume over the southeast Atlantic Ocean
Opinion: Gigacity – a source of problems or the new way to sustainable development
The thermodynamic structures of the planetary boundary layer dominated by synoptic circulations and the regular effect on air pollution in Beijing
Turbulent and boundary layer characteristics during VOCALS-REx
A foehn-induced haze front in Beijing: observations and implications
Airborne measurements and large-eddy simulations of small-scale gravity waves at the tropopause inversion layer over Scandinavia
Observational analysis of the daily cycle of the planetary boundary layer in the central Amazon during a non-El Niño year and El Niño year (GoAmazon project 2014/5)
Planetary boundary layer evolution over the Amazon rainforest in episodes of deep moist convection at the Amazon Tall Tower Observatory
Dominant patterns of summer ozone pollution in eastern China and associated atmospheric circulations
What controls the formation of nocturnal low-level stratus clouds over southern West Africa during the monsoon season?
Recent trends in climate variability at the local scale using 40 years of observations: the case of the Paris region of France
Nocturnal boundary layer turbulence regimes analysis during the BLLAST campaign
Low-level stratiform clouds and dynamical features observed within the southern West African monsoon
Residual layer ozone, mixing, and the nocturnal jet in California's San Joaquin Valley
From weak to intense downslope winds: origin, interaction with boundary-layer turbulence and impact on CO2 variability
On the fine vertical structure of the low troposphere over the coastal margins of East Antarctica
Spatial and temporal variability of turbulence dissipation rate in complex terrain
Characterizing wind gusts in complex terrain
Long-term trends of instability and associated parameters over the Indian region obtained using a radiosonde network
Implication of tropical lower stratospheric cooling in recent trends in tropical circulation and deep convective activity
The observed diurnal cycle of low-level stratus clouds over southern West Africa: a case study
Nocturnal low-level clouds in the atmospheric boundary layer over southern West Africa: an observation-based analysis of conditions and processes
Ju Li, Jingjiang Zhang, Mengxin Bai, Jie Su, Qingchun Li, and Xingcan Jia
EGUsphere, https://doi.org/10.5194/egusphere-2024-2684, https://doi.org/10.5194/egusphere-2024-2684, 2025
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This research examines foehn events in Beijing using weather station data from 2015 to 2020. We found an average of 56.5 foehn days annually, primarily in winter. These winds can raise temperatures significantly and are associated with air-pollution levels. Strong foehn winds tend to reduce pollution, while weaker winds may increase it. Our study highlights the impact of foehn events on air quality, providing valuable insights for urban planning and environmental management.
Xiaoyu Sun, Katrin Müller, Mathias Palm, Christoph Ritter, Denghui Ji, Tim Balthasar Röpke, and Justus Notholt
EGUsphere, https://doi.org/10.5194/egusphere-2024-3981, https://doi.org/10.5194/egusphere-2024-3981, 2025
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We studied how air moves from the lower atmosphere to the stratosphere over the Tropical Western Pacific, a region with very cold temperatures high up. By using ground-based observations and tracking air movement, we found that during winter, the formation of thin cloud allow air to rise, while in summer, most of the air sinks down. This process changes the water vapor amount in the stratosphere, which influences the greenhouse effect and plays an important role in climate change.
Tanguy Jonville, Maurus Borne, Cyrille Flamant, Juan Cuesta, Olivier Bock, Pierre Bosser, Christophe Lavaysse, Andreas Fink, and Peter Knippertz
EGUsphere, https://doi.org/10.5194/egusphere-2024-3606, https://doi.org/10.5194/egusphere-2024-3606, 2025
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Tropical waves structure the atmosphere. Four types of tropical waves (ER, Kelvin, MRG-TD1, and MRG-TD2) are studied using filters, satellite measurements, and in situ data from the Clouds-Atmosphere Dynamics-Dust Interaction in West Africa (CADDIWA) campaign held in September 2021 in Cabo Verde. ER waves impact temperature and humidity above 2500 m, MRG-TD1 around 3500 m, and MRG-TD2 around 2000 m. Interactions between these waves favor tropical cyclone formation.
Martial Haeffelin, Jean-François Ribaud, Jonnathan Céspedes, Jean-Charles Dupont, Aude Lemonsu, Valéry Masson, Tim Nagel, and Simone Kotthaus
Atmos. Chem. Phys., 24, 14101–14122, https://doi.org/10.5194/acp-24-14101-2024, https://doi.org/10.5194/acp-24-14101-2024, 2024
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This study highlights how the state of the urban atmospheric boundary layer impacts urban park cooling effect intensity at night. Under summertime heat wave conditions, the urban atmosphere becomes stable at night, which inhibits turbulent motions. Under those specific conditions, urban parks and woods cool much more efficiently than the surrounding built-up neighbourhoods in the evening and through the night, providing cooler air temperatures by 4 to 6° C depending on park size.
Maciej Karasewicz, Marta Wacławczyk, Pablo Ortiz-Amezcua, Łucja Janicka, Patryk Poczta, Camilla Kassar Borges, and Iwona S. Stachlewska
Atmos. Chem. Phys., 24, 13231–13251, https://doi.org/10.5194/acp-24-13231-2024, https://doi.org/10.5194/acp-24-13231-2024, 2024
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This work concerns analysis of turbulence in the atmospheric boundary layer shortly before sunset. Based on a large set of measurements at a rural and an urban site, we analyze how turbulence properties change in time during rapid decay of convection. We explain the observations using recent theories of non-equilibrium turbulence. The presence of non-equilibrium suggests that classical parametrization schemes fail to predict turbulence statistics shortly before sunset.
Lian Su, Chunsong Lu, Jinlong Yuan, Xiaofei Wang, Qing He, and Haiyun Xia
Atmos. Chem. Phys., 24, 10947–10963, https://doi.org/10.5194/acp-24-10947-2024, https://doi.org/10.5194/acp-24-10947-2024, 2024
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The cold downhill airflow of the Tibetan Plateau leading to the low-level jet weakens the height and intensity of the inversion layer, which reduces the energy demand for the broken inversion layer. The low-level jet causes dust aerosols to accumulate near the ground. The material conditions for the development of the desert atmospheric boundary layer can be quickly transformed into thermal conditions.
Mohammad Allouche, Vladislav I. Sevostianov, Einara Zahn, Mark A. Zondlo, Nelson Luís Dias, Gabriel G. Katul, Jose D. Fuentes, and Elie Bou-Zeid
Atmos. Chem. Phys., 24, 9697–9711, https://doi.org/10.5194/acp-24-9697-2024, https://doi.org/10.5194/acp-24-9697-2024, 2024
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The significance of surface–atmosphere exchanges of aerosol species to atmospheric composition is underscored by their rising concentrations that are modulating the Earth's climate and having detrimental consequences for human health and the environment. Estimating these exchanges, using field measurements, and offering alternative models are the aims here. Limitations in measuring some species misrepresent their actual exchanges, so our proposed models serve to better quantify them.
Manfred Wendisch, Susanne Crewell, André Ehrlich, Andreas Herber, Benjamin Kirbus, Christof Lüpkes, Mario Mech, Steven J. Abel, Elisa F. Akansu, Felix Ament, Clémantyne Aubry, Sebastian Becker, Stephan Borrmann, Heiko Bozem, Marlen Brückner, Hans-Christian Clemen, Sandro Dahlke, Georgios Dekoutsidis, Julien Delanoë, Elena De La Torre Castro, Henning Dorff, Regis Dupuy, Oliver Eppers, Florian Ewald, Geet George, Irina V. Gorodetskaya, Sarah Grawe, Silke Groß, Jörg Hartmann, Silvia Henning, Lutz Hirsch, Evelyn Jäkel, Philipp Joppe, Olivier Jourdan, Zsofia Jurányi, Michail Karalis, Mona Kellermann, Marcus Klingebiel, Michael Lonardi, Johannes Lucke, Anna E. Luebke, Maximilian Maahn, Nina Maherndl, Marion Maturilli, Bernhard Mayer, Johanna Mayer, Stephan Mertes, Janosch Michaelis, Michel Michalkov, Guillaume Mioche, Manuel Moser, Hanno Müller, Roel Neggers, Davide Ori, Daria Paul, Fiona M. Paulus, Christian Pilz, Felix Pithan, Mira Pöhlker, Veronika Pörtge, Maximilian Ringel, Nils Risse, Gregory C. Roberts, Sophie Rosenburg, Johannes Röttenbacher, Janna Rückert, Michael Schäfer, Jonas Schaefer, Vera Schemann, Imke Schirmacher, Jörg Schmidt, Sebastian Schmidt, Johannes Schneider, Sabrina Schnitt, Anja Schwarz, Holger Siebert, Harald Sodemann, Tim Sperzel, Gunnar Spreen, Bjorn Stevens, Frank Stratmann, Gunilla Svensson, Christian Tatzelt, Thomas Tuch, Timo Vihma, Christiane Voigt, Lea Volkmer, Andreas Walbröl, Anna Weber, Birgit Wehner, Bruno Wetzel, Martin Wirth, and Tobias Zinner
Atmos. Chem. Phys., 24, 8865–8892, https://doi.org/10.5194/acp-24-8865-2024, https://doi.org/10.5194/acp-24-8865-2024, 2024
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The Arctic is warming faster than the rest of the globe. Warm-air intrusions (WAIs) into the Arctic may play an important role in explaining this phenomenon. Cold-air outbreaks (CAOs) out of the Arctic may link the Arctic climate changes to mid-latitude weather. In our article, we describe how to observe air mass transformations during CAOs and WAIs using three research aircraft instrumented with state-of-the-art remote-sensing and in situ measurement devices.
Andreas Walbröl, Janosch Michaelis, Sebastian Becker, Henning Dorff, Kerstin Ebell, Irina Gorodetskaya, Bernd Heinold, Benjamin Kirbus, Melanie Lauer, Nina Maherndl, Marion Maturilli, Johanna Mayer, Hanno Müller, Roel A. J. Neggers, Fiona M. Paulus, Johannes Röttenbacher, Janna E. Rückert, Imke Schirmacher, Nils Slättberg, André Ehrlich, Manfred Wendisch, and Susanne Crewell
Atmos. Chem. Phys., 24, 8007–8029, https://doi.org/10.5194/acp-24-8007-2024, https://doi.org/10.5194/acp-24-8007-2024, 2024
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To support the interpretation of the data collected during the HALO-(AC)3 campaign, which took place in the North Atlantic sector of the Arctic from 7 March to 12 April 2022, we analyze how unusual the weather and sea ice conditions were with respect to the long-term climatology. From observations and ERA5 reanalysis, we found record-breaking warm air intrusions and a large variety of marine cold air outbreaks. Sea ice concentration was mostly within the climatological interquartile range.
Shai Abir, Hamish A. McGowan, Yonatan Shaked, Hezi Gildor, Efrat Morin, and Nadav G. Lensky
Atmos. Chem. Phys., 24, 6177–6195, https://doi.org/10.5194/acp-24-6177-2024, https://doi.org/10.5194/acp-24-6177-2024, 2024
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Understanding air–sea heat exchange is vital for studying ocean dynamics. Eddy covariance measurements over the Gulf of Eilat revealed a 3.22 m yr-1 evaporation rate, which is inconsistent with bulk formulae estimations in stable atmospheric conditions, requiring bulk formulae to be revisited in these environments. The surface fluxes have a net cooling effect on the gulf water on an annual mean (-79 W m-2), balanced by a strong exchange flux between the Red Sea and the Gulf of Eilat.
Gina C. Jozef, John J. Cassano, Sandro Dahlke, Mckenzie Dice, Christopher J. Cox, and Gijs de Boer
Atmos. Chem. Phys., 24, 1429–1450, https://doi.org/10.5194/acp-24-1429-2024, https://doi.org/10.5194/acp-24-1429-2024, 2024
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Observations collected during MOSAiC were used to identify the range in vertical structure and stability of the central Arctic lower atmosphere through a self-organizing map analysis. Characteristics of wind features (such as low-level jets) and atmospheric moisture features (such as clouds) were analyzed in the context of the varying vertical structure and stability. Thus, the results of this paper give an overview of the thermodynamic and kinematic features of the central Arctic atmosphere.
Elisa F. Akansu, Sandro Dahlke, Holger Siebert, and Manfred Wendisch
Atmos. Chem. Phys., 23, 15473–15489, https://doi.org/10.5194/acp-23-15473-2023, https://doi.org/10.5194/acp-23-15473-2023, 2023
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The height of the mixing layer is an important measure of the surface-level distribution of energy or other substances. The experimental determination of this height is associated with large uncertainties, particularly under stable conditions that we often find during the polar night or in the presence of clouds. We present a reference method using turbulence measurements on a tethered balloon, which allows us to evaluate approaches based on radiosondes or surface observations.
Ulrike Egerer, Holger Siebert, Olaf Hellmuth, and Lise Lotte Sørensen
Atmos. Chem. Phys., 23, 15365–15373, https://doi.org/10.5194/acp-23-15365-2023, https://doi.org/10.5194/acp-23-15365-2023, 2023
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Low-level jets (LLJs) are strong winds near the surface and occur frequently in the Arctic in stable conditions. Using tethered-balloon profile measurements in Greenland, we analyze a multi-hour period with an LLJ that later weakens and finally collapses. Increased shear-induced turbulence at the LLJ bounds mostly does not reach the ground until the LLJ collapses. Our findings support the hypothesis that a passive tracer can be advected with an LLJ and mixed down when the LLJ collapses.
Dean Henze, David Noone, and Darin Toohey
Atmos. Chem. Phys., 23, 15269–15288, https://doi.org/10.5194/acp-23-15269-2023, https://doi.org/10.5194/acp-23-15269-2023, 2023
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The interaction between biomass burning aerosols and clouds remains challenging to accurately determine from observations. This is in part because of difficulties distinguishing aerosol differences due to precipitation versus dilution processes from the observations. This study addresses the challenge by utilizing atmospheric heavy water isotope ratios to constrain mixing versus precipitation processes during a field campaign (ORACLES) and in turn explain observed aerosol concentrations.
Zefan Ju, Jian Rao, Yue Wang, Junfeng Yang, and Qian Lu
Atmos. Chem. Phys., 23, 14903–14918, https://doi.org/10.5194/acp-23-14903-2023, https://doi.org/10.5194/acp-23-14903-2023, 2023
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In the paper, we explored the impact of the Madden–Julian Oscillation (MJO) and the Quasi-Biennial Oscillation (QBO) on East China summer rainfall variability. It is novel to find that the combined impact of MJO and QBO is not maximized when the QBO and MJO are in phase to enhance (or suppress) the tropical convection.
Gina C. Jozef, John J. Cassano, Sandro Dahlke, Mckenzie Dice, Christopher J. Cox, and Gijs de Boer
Atmos. Chem. Phys., 23, 13087–13106, https://doi.org/10.5194/acp-23-13087-2023, https://doi.org/10.5194/acp-23-13087-2023, 2023
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Observations from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) were used to determine the frequency of occurrence of various central Arctic lower atmospheric stability regimes and how the stability regimes transition between each other. Wind and radiation observations were analyzed in the context of stability regime and season to reveal the relationships between Arctic atmospheric stability and mechanically and radiatively driven turbulent forcings.
Jia Shao, Jian Zhang, Wuke Wang, Shaodong Zhang, Tao Yu, and Wenjun Dong
Atmos. Chem. Phys., 23, 12589–12607, https://doi.org/10.5194/acp-23-12589-2023, https://doi.org/10.5194/acp-23-12589-2023, 2023
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Kelvin–Helmholtz instability (KHI) is indicated by the critical value of the Richardson (Ri) number, which is usually predicted to be 1/4. Compared to high-resolution radiosondes, the threshold value of Ri could be approximated as 1 rather than 1/4 when using ERA5-based Ri as a proxy for KHI. The occurrence frequency of subcritical Ri exhibits significant seasonal cycles over all climate zones and is closely associated with gravity waves and background flows.
Shijie Peng, Qinghua Yang, Matthew D. Shupe, Xingya Xi, Bo Han, Dake Chen, Sandro Dahlke, and Changwei Liu
Atmos. Chem. Phys., 23, 8683–8703, https://doi.org/10.5194/acp-23-8683-2023, https://doi.org/10.5194/acp-23-8683-2023, 2023
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Due to a lack of observations, the structure of the Arctic atmospheric boundary layer (ABL) remains to be further explored. By analyzing a year-round radiosonde dataset collected over the Arctic sea-ice surface, we found the annual cycle of the ABL height (ABLH) is primarily controlled by the evolution of ABL thermal structure, and the surface conditions also show a high correlation with ABLH variation. In addition, the Arctic ABLH is found to be decreased in summer compared with 20 years ago.
Dmitry G. Chechin, Christof Lüpkes, Jörg Hartmann, André Ehrlich, and Manfred Wendisch
Atmos. Chem. Phys., 23, 4685–4707, https://doi.org/10.5194/acp-23-4685-2023, https://doi.org/10.5194/acp-23-4685-2023, 2023
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Clouds represent a very important component of the Arctic climate system, as they strongly reduce the amount of heat lost to space from the sea ice surface. Properties of clouds, as well as their persistence, strongly depend on the complex interaction of such small-scale properties as phase transitions, radiative transfer and turbulence. In this study we use airborne observations to learn more about the effect of clouds and radiative cooling on turbulence in comparison with other factors.
Noviana Dewani, Mirjana Sakradzija, Linda Schlemmer, Ronny Leinweber, and Juerg Schmidli
Atmos. Chem. Phys., 23, 4045–4058, https://doi.org/10.5194/acp-23-4045-2023, https://doi.org/10.5194/acp-23-4045-2023, 2023
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A high daily variability of the normalized vertical velocity variance profiles in the convective boundary layer is observed using Doppler lidar data during the FESSTVaL campaign 2020–2021. The dependency of the normalized vertical velocity variance on several meteorological parameters explains that the moisture processes in the boundary layer contribute to the remaining variability. The finding suggests that a new vertical velocity scale that takes moist processes into account has to be defined.
Xiangde Xu, Yi Tang, Yinjun Wang, Hongshen Zhang, Ruixia Liu, and Mingyu Zhou
Atmos. Chem. Phys., 23, 3299–3309, https://doi.org/10.5194/acp-23-3299-2023, https://doi.org/10.5194/acp-23-3299-2023, 2023
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The vertical motion over the Tibetan Plateau (TP) is associated with the anomalous convective activities. The diurnal variations and formation mechanisms of low clouds over the TP, Rocky Mountains and low-elevation regions are analyzed. We further discuss whether there exists a
high-efficiencytriggering mechanism for convection over the TP and whether there is an association among low air density and strong turbulence and ubiquitous popcorn-like cumulus clouds.
Lejiang Yu, Shiyuan Zhong, Timo Vihma, Cuijuan Sui, and Bo Sun
Atmos. Chem. Phys., 23, 345–353, https://doi.org/10.5194/acp-23-345-2023, https://doi.org/10.5194/acp-23-345-2023, 2023
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Previous studies have noted a significant relationship between the Subtropical Indian Ocean Dipole and the South Atlantic Ocean Dipole indices, but little is known about the stability of their relationship. We found a significant positive correlation between the two indices prior to the year 2000 but an insignificant correlation afterwards.
Si Cheng, Jianguo Wang, Li Cai, Mi Zhou, Rui Su, Yijun Huang, and Quanxin Li
Atmos. Chem. Phys., 22, 10045–10059, https://doi.org/10.5194/acp-22-10045-2022, https://doi.org/10.5194/acp-22-10045-2022, 2022
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This paper helps to improve the recognition of severe thunderstorms in advance by giving a general understanding of how long the storm lasts, how fast the cluster moves and how much area the storm affects via information about the kinematic features of thunderstorms, which are the duration, valid area, the velocity, the direction and the farthest distance, and ideally to establish a foundation for future research that may contribute to the development of a new or improved prediction paradigm.
Hongyou Liu, Yanxiong Shi, and Xiaojing Zheng
Atmos. Chem. Phys., 22, 8787–8803, https://doi.org/10.5194/acp-22-8787-2022, https://doi.org/10.5194/acp-22-8787-2022, 2022
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The sandstorm, which is a common natural disaster, is mechanically characterized by a particle-laden flow experiencing wall turbulence. This work investigates a real sandstorm that was measured at the Qingtu Lake Observation Array through a lens of wall-turbulent flow dynamics. A non-stationary signal processing method is proposed based on the time-varying mean and adaptive segmented stationary method, and the evolution of turbulent kinetic energy during the entire sandstorm process is revealed.
Simon Kirschler, Christiane Voigt, Bruce Anderson, Ramon Campos Braga, Gao Chen, Andrea F. Corral, Ewan Crosbie, Hossein Dadashazar, Richard A. Ferrare, Valerian Hahn, Johannes Hendricks, Stefan Kaufmann, Richard Moore, Mira L. Pöhlker, Claire Robinson, Amy J. Scarino, Dominik Schollmayer, Michael A. Shook, K. Lee Thornhill, Edward Winstead, Luke D. Ziemba, and Armin Sorooshian
Atmos. Chem. Phys., 22, 8299–8319, https://doi.org/10.5194/acp-22-8299-2022, https://doi.org/10.5194/acp-22-8299-2022, 2022
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In this study we show that the vertical velocity dominantly impacts the cloud droplet number concentration (NC) of low-level clouds over the western North Atlantic in the winter and summer season, while the cloud condensation nuclei concentration, aerosol size distribution and chemical composition impact NC within a season. The observational data presented in this study can evaluate and improve the representation of aerosol–cloud interactions for a wide range of conditions.
Klaus Gierens, Lena Wilhelm, Sina Hofer, and Susanne Rohs
Atmos. Chem. Phys., 22, 7699–7712, https://doi.org/10.5194/acp-22-7699-2022, https://doi.org/10.5194/acp-22-7699-2022, 2022
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We are interested in the prediction of condensation trails, in particular strong ones. For this we need a good forecast of temperature and humidity in the levels where aircraft cruise. Unfortunately, the humidity forecast is quite difficult for these levels, in particular the ice supersaturation, which is needed for long-lasting contrails. We are thus seeking proxy variables that help distinguish situations where strong contrails can form, for instance the lapse rate.
Ada Mariska Koning, Louise Nuijens, Christian Mallaun, Benjamin Witschas, and Christian Lemmerz
Atmos. Chem. Phys., 22, 7373–7388, https://doi.org/10.5194/acp-22-7373-2022, https://doi.org/10.5194/acp-22-7373-2022, 2022
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Wind measurements from the mixed layer to cloud tops are scarce, causing a lack of knowledge on wind mixing between and within these layers. We use airborne observations of wind profiles and local wind at high frequency to study wind transport in cloud fields. A case with thick clouds had its maximum transport in the cloud layer, caused by eddies > 700 m, which was not expected from turbulence theory. In other cases large eddies undid transport of smaller eddies resulting in no net transport.
Markus Geldenhuys, Peter Preusse, Isabell Krisch, Christoph Zülicke, Jörn Ungermann, Manfred Ern, Felix Friedl-Vallon, and Martin Riese
Atmos. Chem. Phys., 21, 10393–10412, https://doi.org/10.5194/acp-21-10393-2021, https://doi.org/10.5194/acp-21-10393-2021, 2021
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A large-scale gravity wave (GW) was observed spanning the whole of Greenland. The GWs proposed in this paper come from a new jet–topography mechanism. The topography compresses the flow and triggers a change in u- and
v-wind components. The jet becomes out of geostrophic balance and sheds energy in the form of GWs to restore the balance. This topography–jet interaction was not previously considered by the community, rendering the impact of the gravity waves largely unaccounted for.
Kristina Pistone, Paquita Zuidema, Robert Wood, Michael Diamond, Arlindo M. da Silva, Gonzalo Ferrada, Pablo E. Saide, Rei Ueyama, Ju-Mee Ryoo, Leonhard Pfister, James Podolske, David Noone, Ryan Bennett, Eric Stith, Gregory Carmichael, Jens Redemann, Connor Flynn, Samuel LeBlanc, Michal Segal-Rozenhaimer, and Yohei Shinozuka
Atmos. Chem. Phys., 21, 9643–9668, https://doi.org/10.5194/acp-21-9643-2021, https://doi.org/10.5194/acp-21-9643-2021, 2021
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Using aircraft-based measurements off the Atlantic coast of Africa, we found the springtime smoke plume was strongly correlated with the amount of water vapor in the atmosphere (more smoke indicated more humidity). We see the same general feature in satellite-assimilated and free-running models. Our analysis suggests this relationship is not caused by the burning but originates due to coincident continental meteorology plus fires. This air is transported over the ocean without further mixing.
Markku Kulmala, Tom V. Kokkonen, Juha Pekkanen, Sami Paatero, Tuukka Petäjä, Veli-Matti Kerminen, and Aijun Ding
Atmos. Chem. Phys., 21, 8313–8322, https://doi.org/10.5194/acp-21-8313-2021, https://doi.org/10.5194/acp-21-8313-2021, 2021
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The eastern part of China as a whole is practically a gigacity with 650 million inhabitants. The gigacity, with its emissions, processes in the pollution cocktail and numerous feedbacks and interactions, has a crucial and big impact on regional air quality and on global climate. A large-scale research and innovation program is needed to meet the interlinked grand challenges in this gigacity and to serve as a platform for finding pathways for sustainable development of the globe.
Yunyan Jiang, Jinyuan Xin, Ying Wang, Guiqian Tang, Yuxin Zhao, Danjie Jia, Dandan Zhao, Meng Wang, Lindong Dai, Lili Wang, Tianxue Wen, and Fangkun Wu
Atmos. Chem. Phys., 21, 6111–6128, https://doi.org/10.5194/acp-21-6111-2021, https://doi.org/10.5194/acp-21-6111-2021, 2021
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Multiscale-circulation coupling affects pollution by changing the planetary boundary layer (PBL) structure. The multilayer PBL under cyclonic circulation has no diurnal variation; the temperature inversion and zero-speed zone can reach 600–900 m with strong mountain winds. The monolayer PBL under southwestern circulation can reach 2000 m; the inversion is lower than nocturnal PBL (400 m) with strong ambient winds. The zonal winds' vertical shear produces the inversion under western circulation.
Dillon S. Dodson and Jennifer D. Small Griswold
Atmos. Chem. Phys., 21, 1937–1961, https://doi.org/10.5194/acp-21-1937-2021, https://doi.org/10.5194/acp-21-1937-2021, 2021
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The results here reinforce findings from previous in situ studies of the marine boundary layer. It is found that turbulence is maximized in the middle of the stratocumulus layer from latent heating effects. Precipitation acts to increase turbulence in the sub-cloud layer, while acting to stabilize the entire boundary layer after the evaporation of precipitation in the sub-cloud has stopped. A negative correlation is present between the boundary layer height and turbulence.
Ju Li, Zhaobin Sun, Donald H. Lenschow, Mingyu Zhou, Youjun Dou, Zhigang Cheng, Yaoting Wang, and Qingchun Li
Atmos. Chem. Phys., 20, 15793–15809, https://doi.org/10.5194/acp-20-15793-2020, https://doi.org/10.5194/acp-20-15793-2020, 2020
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We analyzed a haze front event involving warm–dry downslope flow in December 2015 in Beijing, China. The haze front was formed by the collision between a clean warm–dry air mass flowing from a nearby mountainous region and a polluted cold–wet air mass over an urban area. We found that the polluted air advanced toward the clean air, resulting in a severe air pollution event. Our study highlights the need to further investigate the warm–dry downslope and its impacts on air pollution.
Sonja Gisinger, Johannes Wagner, and Benjamin Witschas
Atmos. Chem. Phys., 20, 10091–10109, https://doi.org/10.5194/acp-20-10091-2020, https://doi.org/10.5194/acp-20-10091-2020, 2020
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Gravity waves are an important coupling mechanism in the atmosphere. Measurements by two research aircraft during a mountain wave event over Scandinavia in 2016 revealed changes of the horizontal scales in the vertical velocity field and of momentum fluxes in the vicinity of the tropopause inversion. Idealized simulations revealed the presence of interfacial waves. They are found downstream of the mountain peaks, meaning that they horizontally transport momentum/energy away from their source.
Rayonil G. Carneiro and Gilberto Fisch
Atmos. Chem. Phys., 20, 5547–5558, https://doi.org/10.5194/acp-20-5547-2020, https://doi.org/10.5194/acp-20-5547-2020, 2020
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The objective of this study was to conduct observational evaluations of the daily cycle of the height of the planetary boundary layer from data that were measured and/or estimated using instruments such as a radiosonde, sodar, ceilometer, wind profiler, lidar and microwave radiometer installed in the central Amazon during 2014 (considered a typical year) and 2015 during which an intense El Niño–Southern Oscillation (ENSO) event predominated during the GoAmazon experiment.
Maurício I. Oliveira, Otávio C. Acevedo, Matthias Sörgel, Ernani L. Nascimento, Antonio O. Manzi, Pablo E. S. Oliveira, Daiane V. Brondani, Anywhere Tsokankunku, and Meinrat O. Andreae
Atmos. Chem. Phys., 20, 15–27, https://doi.org/10.5194/acp-20-15-2020, https://doi.org/10.5194/acp-20-15-2020, 2020
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In this study, data collected during four deep convection events at the 80 m tower from the Amazon Tall Tower Observatory are analyzed. It provides a unique view on how such events affect the local boundary layer and how it recovers after their passage. Quantities analyzed include mean wind speed, virtual potential temperature, turbulent kinetic energy, sensible, and latent heat fluxes. A conceptual model for boundary layer structure along the passage of deep convection events is proposed.
Zhicong Yin, Bufan Cao, and Huijun Wang
Atmos. Chem. Phys., 19, 13933–13943, https://doi.org/10.5194/acp-19-13933-2019, https://doi.org/10.5194/acp-19-13933-2019, 2019
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Ozone occurs both in the stratosphere and at ground level. Surface ozone is a man-made air pollutant and has harmful effects on people and the environment. Two dominant patterns of summer ozone pollution were determined. The most dominant pattern in 2017 and 2018 was different from that in previous years. The findings of this study help us to understand the features of surface ozone pollution in eastern China and their relationships with large-scale atmospheric circulations.
Karmen Babić, Norbert Kalthoff, Bianca Adler, Julian F. Quinting, Fabienne Lohou, Cheikh Dione, and Marie Lothon
Atmos. Chem. Phys., 19, 13489–13506, https://doi.org/10.5194/acp-19-13489-2019, https://doi.org/10.5194/acp-19-13489-2019, 2019
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This study investigates differences in atmospheric conditions between nights with and without low-level stratus clouds (LLCs) over southern West Africa. We use high-quality observations collected during 2016 summer monsoon season and the ERA5 reanalysis data set. Our results show that the formation of LLCs depends on the interplay between the onset time and strength of the nocturnal low-level jet, horizontal cold-air advection, and the overall moisture level in the whole region.
Justine Ringard, Marjolaine Chiriaco, Sophie Bastin, and Florence Habets
Atmos. Chem. Phys., 19, 13129–13155, https://doi.org/10.5194/acp-19-13129-2019, https://doi.org/10.5194/acp-19-13129-2019, 2019
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This study characterizes the changes observed at Paris urban scale and attempts to identify the surface–atmosphere feedbacks likely to explain the trends observed as a function of the different configurations of large-scale dynamics. This article is interested in several atmospheric parameters and their possible retroactions. Finally, to study urban environments, the analysis at the local scale is essential because it is very poorly represented in the model.
Jesús Yus-Díez, Mireia Udina, Maria Rosa Soler, Marie Lothon, Erik Nilsson, Joan Bech, and Jielun Sun
Atmos. Chem. Phys., 19, 9495–9514, https://doi.org/10.5194/acp-19-9495-2019, https://doi.org/10.5194/acp-19-9495-2019, 2019
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This study helps improve the understanding of the turbulence description and the interactions occurring in the lower part of the boundary layer. It is carried out at an orographically influenced site close to the Pyrenees to explore the hockey-stick transition (HOST) theory. HOST is seen to be strongly dependent on both the meteorological conditions and the orographic features. Examples of intermittent turbulence events that lead to transitions between the turbulence regimes are also identified.
Cheikh Dione, Fabienne Lohou, Marie Lothon, Bianca Adler, Karmen Babić, Norbert Kalthoff, Xabier Pedruzo-Bagazgoitia, Yannick Bezombes, and Omar Gabella
Atmos. Chem. Phys., 19, 8979–8997, https://doi.org/10.5194/acp-19-8979-2019, https://doi.org/10.5194/acp-19-8979-2019, 2019
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Low atmospheric dynamics and low-level cloud (LLC) macrophysical properties are analyzed using in situ and remote sensing data collected from 20 June to 30 July at Savè, Benin, during the DACCIWA field campaign in 2016. We find that the low-level jet (LLJ), LLCs, monsoon flow, and maritime inflow reveal a day-to-day variability. LLCs form at the same level as the jet core height. The cloud base height is stationary at night and remains below the jet. The cloud top height is found above the jet.
Dani J. Caputi, Ian Faloona, Justin Trousdell, Jeanelle Smoot, Nicholas Falk, and Stephen Conley
Atmos. Chem. Phys., 19, 4721–4740, https://doi.org/10.5194/acp-19-4721-2019, https://doi.org/10.5194/acp-19-4721-2019, 2019
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This paper covers the importance of understanding ozone pollution in California’s southern San Joaquin Valley from the perspective of meteorological conditions that occur overnight. Our main finding is that stronger winds aloft allow ozone to be depleted overnight, leading to less ozone the following day. This finding has the potential to greatly improve ozone forecasts in the San Joaquin Valley. This study is primarily conducted with aircraft observations.
Jon Ander Arrillaga, Carlos Yagüe, Carlos Román-Cascón, Mariano Sastre, Maria Antonia Jiménez, Gregorio Maqueda, and Jordi Vilà-Guerau de Arellano
Atmos. Chem. Phys., 19, 4615–4635, https://doi.org/10.5194/acp-19-4615-2019, https://doi.org/10.5194/acp-19-4615-2019, 2019
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Thermally driven downslope winds develop in mountainous areas under a weak large-scale forcing and clear skies. In this work, we find that their onset time and intensity are closely connected with both the large-scale wind and soil moisture. We also show how the distinct downslope intensities shape the turbulent and thermal features of the nocturnal atmosphere. The analysis concludes that the downslope–turbulence interaction and the horizontal transport explain the important CO2 variability.
Étienne Vignon, Olivier Traullé, and Alexis Berne
Atmos. Chem. Phys., 19, 4659–4683, https://doi.org/10.5194/acp-19-4659-2019, https://doi.org/10.5194/acp-19-4659-2019, 2019
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The future sea-level rise will depend on how much the Antarctic ice sheet gain – via precipitation – or loose mass. The simulation of precipitation by numerical models used for projections depends on the representation of the atmospheric circulation over and around Antarctica. Using daily measurements from balloon soundings at nine Antarctic stations, this study characterizes the structure of the atmosphere over the Antarctic coast and its representation in atmospheric simulations.
Nicola Bodini, Julie K. Lundquist, Raghavendra Krishnamurthy, Mikhail Pekour, Larry K. Berg, and Aditya Choukulkar
Atmos. Chem. Phys., 19, 4367–4382, https://doi.org/10.5194/acp-19-4367-2019, https://doi.org/10.5194/acp-19-4367-2019, 2019
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To improve the parameterization of the turbulence dissipation rate (ε) in numerical weather prediction models, we have assessed its temporal and spatial variability at various scales in the Columbia River Gorge during the WFIP2 field experiment. The turbulence dissipation rate shows large spatial variability, even at the microscale, with larger values in sites located downwind of complex orographic structures or in wind farm wakes. Distinct diurnal and seasonal cycles in ε have also been found.
Frederick Letson, Rebecca J. Barthelmie, Weifei Hu, and Sara C. Pryor
Atmos. Chem. Phys., 19, 3797–3819, https://doi.org/10.5194/acp-19-3797-2019, https://doi.org/10.5194/acp-19-3797-2019, 2019
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Wind gusts are a key driver of aerodynamic loading, and common approximations used to describe wind gust behavior may not be appropriate in complex terrain at heights relevant to wind turbines and other structures. High-resolution observations from sonic anemometers and vertically pointing Doppler lidars collected in the Perdigão experiment are analyzed to provide a foundation for improved wind gust characterization in complex terrain.
Rohit Chakraborty, Madineni Venkat Ratnam, and Shaik Ghouse Basha
Atmos. Chem. Phys., 19, 3687–3705, https://doi.org/10.5194/acp-19-3687-2019, https://doi.org/10.5194/acp-19-3687-2019, 2019
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Intense convective phenomena are a common climatic feature in the Indian tropical region which occur during the pre-monsoon to post-monsoon seasons (April–October) and are generally accompanied by intense thunderstorms, lightning, and wind gusts with heavy rainfall. Here we show long-term trends of the parameters related to convection and instability obtained from 27 radiosonde stations across six subdivisions over the Indian region during the period 1980–2016.
Kunihiko Kodera, Nawo Eguchi, Rei Ueyama, Yuhji Kuroda, Chiaki Kobayashi, Beatriz M. Funatsu, and Chantal Claud
Atmos. Chem. Phys., 19, 2655–2669, https://doi.org/10.5194/acp-19-2655-2019, https://doi.org/10.5194/acp-19-2655-2019, 2019
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The recent cooling of the equatorial eastern Pacific Ocean occurred in conjunction with enhanced cross-equatorial southerlies associated with a strengthening of the boreal summer Hadley circulation. A combination of land surface warming and reduced static stability in the tropical tropopause layer due to stratospheric cooling is suggested to have caused the increase in the deep ascending branch of the Hadley circulation and related recent decadal change in the tropical troposphere and ocean.
Karmen Babić, Bianca Adler, Norbert Kalthoff, Hendrik Andersen, Cheikh Dione, Fabienne Lohou, Marie Lothon, and Xabier Pedruzo-Bagazgoitia
Atmos. Chem. Phys., 19, 1281–1299, https://doi.org/10.5194/acp-19-1281-2019, https://doi.org/10.5194/acp-19-1281-2019, 2019
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The first detailed observational analysis of the complete diurnal cycle of low-level clouds (LLC) and associated atmospheric processes over southern West Africa is performed using the data gathered within the DACCIWA (Dynamics-Aerosol-Chemistry-Cloud-Interactions in West Africa) ground-based campaign. We find cooling related to the horizontal advection, which occurs in connection with the inflow of cool maritime air mass and a prominent low-level jet, to have the dominant role in LLC formation.
Bianca Adler, Karmen Babić, Norbert Kalthoff, Fabienne Lohou, Marie Lothon, Cheikh Dione, Xabier Pedruzo-Bagazgoitia, and Hendrik Andersen
Atmos. Chem. Phys., 19, 663–681, https://doi.org/10.5194/acp-19-663-2019, https://doi.org/10.5194/acp-19-663-2019, 2019
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This study deals with nocturnal stratiform low-level clouds that frequently form in the atmospheric boundary layer over southern West Africa. We use observational data from 11 nights to characterize the clouds and intranight variability of boundary layer conditions as well as to assess the physical processes relevant for cloud formation. We find that cooling is crucial to reach saturation and a large part of the cooling is related to horizontal advection of cool air from the Gulf of Guinea.
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Short summary
In order to support the evaluation of coupled atmospheric–land-surface models we investigated spatial patterns of energy fluxes in relation to land-surface properties and upscaled airborne flux measurements to high resolution flux maps. A machine learning technique allows us to estimate environmental response functions between spatially and temporally resolved flux observations and corresponding biophysical and meteorological drivers.
In order to support the evaluation of coupled atmospheric–land-surface models we investigated...
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