Search

Your search keyword '"Dupuy, Régis"' showing total 101 results
Start Over Author "Dupuy, Régis"
101 results on '"Dupuy, Régis"'

2. Publisher Correction: MOSAiC-ACA and AFLUX - Arctic airborne campaigns characterizing the exit area of MOSAiC

Author

Mech, Mario, Ehrlich, André, Herber, Andreas, Lüpkes, Christof, Wendisch, Manfred, Becker, Sebastian, Boose, Yvonne, Chechin, Dmitry, Crewell, Susanne, Dupuy, Régis, Gourbeyre, Christophe, Hartmann, Jörg, Jäkel, Evelyn, Jourdan, Olivier, Kliesch, Leif-Leonard, Klingebiel, Marcus, Kulla, Birte Solveig, Mioche, Guillaume, Moser, Manuel, Risse, Nils, Ruiz-Donoso, Elena, Schäfer, Michael, Stapf, Johannes, and Voigt, Christiane

Published
2023
Full Text
View/download PDF

3. Author Correction: MOSAiC-ACA and AFLUX - Arctic airborne campaigns characterizing the exit area of MOSAiC

Author

Mech, Mario, Ehrlich, André, Herber, Andreas, Lüpkes, Christof, Wendisch, Manfred, Becker, Sebastian, Boose, Yvonne, Chechin, Dmitry, Crewell, Susanne, Dupuy, Régis, Gourbeyre, Christophe, Hartmann, Jörg, Jäkel, Evelyn, Jourdan, Olivier, Kliesch, Leif-Leonard, Klingebiel, Marcus, Kulla, Birte Solveig, Mioche, Guillaume, Moser, Manuel, Risse, Nils, Ruiz-Donoso, Elena, Schäfer, Michael, Stapf, Johannes, and Voigt, Christiane

Published
2023
Full Text
View/download PDF

4. MOSAiC-ACA and AFLUX - Arctic airborne campaigns characterizing the exit area of MOSAiC

Author

Mech, Mario, Ehrlich, André, Herber, Andreas, Lüpkes, Christof, Wendisch, Manfred, Becker, Sebastian, Boose, Yvonne, Chechin, Dmitry, Crewell, Susanne, Dupuy, Régis, Gourbeyre, Christophe, Hartmann, Jörg, Jäkel, Evelyn, Jourdan, Olivier, Kliesch, Leif-Leonard, Klingebiel, Marcus, Kulla, Birte Solveig, Mioche, Guillaume, Moser, Manuel, Risse, Nils, Ruiz-Donoso, Elena, Schäfer, Michael, Stapf, Johannes, and Voigt, Christiane

Published
2022
Full Text
View/download PDF

5. THE ARCTIC CLOUD PUZZLE : Using ACLOUD/PASCAL Multiplatform Observations to Unravel the Role of Clouds and Aerosol Particles in Arctic Amplification

Author

Wendisch, Manfred, Macke, Andreas, Ehrlich, André, Lüpkes, Christof, Mech, Mario, Chechin, Dmitry, Dethloff, Klaus, Velasco, Carola Barrientos, Bozem, Heiko, Brückner, Marlen, Clemen, Hans-Christian, Crewell, Susanne, Donth, Tobias, Dupuy, Regis, Ebell, Kerstin, Egerer, Ulrike, Engelmann, Ronny, Engler, Christa, Eppers, Oliver, Gehrmann, Martin, Gong, Xianda, Gottschalk, Matthias, Gourbeyre, Christophe, Griesche, Hannes, Hartmann, Jörg, Hartmann, Markus, Heinold, Bernd, Herber, Andreas, Herrmann, Hartmut, Heygster, Georg, Hoor, Peter, Jafariserajehlou, Soheila, Jäkel, Evelyn, Järvinen, Emma, Jourdan, Olivier, Kästner, Udo, Kecorius, Simonas, Knudsen, Erlend M., Köllner, Franziska, Kretzschmar, Jan, Lelli, Luca, Leroy, Delphine, Maturilli, Marion, Mei, Linlu, Mertes, Stephan, Mioche, Guillaume, Neuber, Roland, Nicolaus, Marcel, Nomokonova, Tatiana, Notholt, Justus, Palm, Mathias, van Pinxteren, Manuela, Quaas, Johannes, Richter, Philipp, Ruiz-Donoso, Elena, Schäfer, Michael, Schmieder, Katja, Schnaiter, Martin, Schneider, Johannes, Schwarzenböck, Alfons, Seifert, Patric, Shupe, Matthew D., Siebert, Holger, Spreen, Gunnar, Stapf, Johannes, Stratmann, Frank, Vogl, Teresa, Welti, André, Wex, Heike, Wiedensohler, Alfred, Zanatta, Marco, and Zeppenfeld, Sebastian

Published
2019

6. Microphysical and thermodynamic phase analyses of Arctic low-level clouds measured above the sea ice and the open ocean in spring and summer

Author

Moser, Manuel, primary, Voigt, Christiane, additional, Jurkat-Witschas, Tina, additional, Hahn, Valerian, additional, Mioche, Guillaume, additional, Jourdan, Olivier, additional, Dupuy, Régis, additional, Gourbeyre, Christophe, additional, Schwarzenboeck, Alfons, additional, Lucke, Johannes, additional, Boose, Yvonne, additional, Mech, Mario, additional, Borrmann, Stephan, additional, Ehrlich, André, additional, Herber, Andreas, additional, Lüpkes, Christof, additional, and Wendisch, Manfred, additional

Published
2023
Full Text
View/download PDF

7. Impacts of thermodynamics and aerosol particles on Arctic mixed-phase cloud microphysics over different surface conditions

Author

Arteaga, Diana, Wobrock, Wolfram, Banson, Sandra, Dupuy, Régis, Mioche, Guillaume, Tridon, Frédéric, Baray, Jean-Luc, Jourdan, Olivier, and Planche, Celine

Abstract

Different physical processes associated with surface and thermodynamical conditions as well as aerosol concentrations influence the formation and persistence of mixed-phase clouds (MPCs) in the Arctic. This study focuses on the impact of thermodynamical conditions and aerosol concentrations (cloud condensation nuclei (CCN) and ice-nucleating particles (INP)) on cloud microphysical properties. Two Arctic mixed-phase cloud systems measured the 17 June 2017 during the ACLOUD airborne campaign are simulated with the WRF model. In situ microphysical observations of cloud number and mass concentrations performed by aircraft microphysics probes are compared to WRF outputs. To investigate the effect of changing surfaces, two types of scenarios were studied: over sea ice and over open ocean. The MPC over open ocean is characterized by a higher liquid water content (LWC) and a lower ice water content (IWC) compared to the MPC over sea ice. Two microphysics schemes were tested: the two-moment schemes of Morrison and Milbrandt. Sensitivity studies have been carried out to investigate the impact of the thermodynamics, the surface properties and the aerosol loading on the LWC and the IWC. The first sensitivity test shows the large impact of the thermodynamics on the cloud properties since using the ERA5 reanalysis data with different vertical levels for initialization impact the simulated LWC and IWC profiles. Additional studies have been performed highlighting the important role of the CCN and INP on the formation and properties of the studied MPCs., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023

8. Microphysical and thermodynamic phase analyses of Arctic low-level clouds measured above the sea ice and the open ocean in spring and summer.

Author

Moser, Manuel, Voigt, Christiane, Jurkat-Witschas, Tina, Hahn, Valerian, Mioche, Guillaume, Jourdan, Olivier, Dupuy, Régis, Gourbeyre, Christophe, Schwarzenboeck, Alfons, Lucke, Johannes, Boose, Yvonne, Mech, Mario, Borrmann, Stephan, Ehrlich, André, Herber, Andreas, Lüpkes, Christof, and Wendisch, Manfred

Subjects
SEA ice, SPRING, ICE clouds, CLIMATE change models, EFFECT of human beings on climate change, SUMMER, BOUNDARY layer (Aerodynamics)
Abstract

Airborne in situ cloud measurements were carried out over the northern Fram Strait between Greenland and Svalbard in spring 2019 and summer 2020. In total, 811 min of low-level cloud observations were performed during 20 research flights above the sea ice and the open Arctic ocean with the Polar 5 research aircraft of the Alfred Wegener Institute. Here, we combine the comprehensive in situ cloud data to investigate the distributions of particle number concentration N , effective diameter Deff , and cloud water content CWC (liquid and ice) of Arctic clouds below 500 m altitude, measured at latitudes between 76 and 83 ∘ N. We developed a method to quantitatively derive the occurrence probability of their thermodynamic phase from the combination of microphysical cloud probe and Polar Nephelometer data. Finally, we assess changes in cloud microphysics and cloud phase related to ambient meteorological conditions in spring and summer and address effects of the sea ice and open-ocean surface conditions. We find median N from 0.2 to 51.7 cm-3 and about 2 orders of magnitude higher N for mainly liquid clouds in summer compared to ice and mixed-phase clouds measured in spring. A southerly flow from the sea ice in cold air outbreaks dominates cloud formation processes at temperatures mostly below -10 ∘ C in spring, while northerly warm air intrusions favor the formation of liquid clouds at warmer temperatures in summer. Our results show slightly higher N in clouds over the sea ice compared to the open ocean, indicating enhanced cloud formation processes over the sea ice. The median CWC is higher in summer (0.16 gm-3) than in spring (0.06 gm-3), as this is dominated by the available atmospheric water content and the temperatures at cloud formation level. We find large differences in the particle sizes in spring and summer and an impact of the surface conditions, which modifies the heat and moisture fluxes in the boundary layer. By combining microphysical cloud data with thermodynamic phase information from the Polar Nephelometer, we find mixed-phase clouds to be the dominant thermodynamic cloud phase in spring, with a frequency of occurrence of 61 % over the sea ice and 66 % over the ocean. Pure ice clouds exist almost exclusively over the open ocean in spring, and in summer the cloud particles are most likely in the liquid water state. The comprehensive low-level cloud data set will help us to better understand the role of clouds and their thermodynamic phase in the Arctic radiation budget and to assess the performance of global climate models in a region of the world with the strongest anthropogenic climate change. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

12. Sensitivity of low-level clouds and precipitation to anthropogenic aerosol emission in southern West Africa: a DACCIWA case study

Author

Deroubaix, Adrien, primary, Menut, Laurent, additional, Flamant, Cyrille, additional, Knippertz, Peter, additional, Fink, Andreas H., additional, Batenburg, Anneke, additional, Brito, Joel, additional, Denjean, Cyrielle, additional, Dione, Cheikh, additional, Dupuy, Régis, additional, Hahn, Valerian, additional, Kalthoff, Norbert, additional, Lohou, Fabienne, additional, Schwarzenboeck, Alfons, additional, Siour, Guillaume, additional, Tuccella, Paolo, additional, and Voigt, Christiane, additional

Published
2022
Full Text
View/download PDF

13. Sensitivity of low-level clouds and precipitation to anthropogenic aerosol emission in southern West Africa: a DACCIWA case study

Author

Deroubaix, Adrien, primary, Menut, Laurent, additional, Flamant, Cyrille, additional, Knippertz, Peter, additional, Fink, Andreas, additional, Batenburg, Anneke, additional, Brito, Joel, additional, Denjean, Cyrielle, additional, Dione, Cheikh, additional, Dupuy, Régis, additional, Hahn, Valerian, additional, Kalthoff, Norbert, additional, Lohou, Fabienne, additional, Schwarzenboeck, Alfons, additional, Siour, Guillaume, additional, Tuccella, Paolo, additional, and Voigt, Christiane, additional

Published
2021
Full Text
View/download PDF

15. Investigation of several proxies to estimate sulfuric acid concentration under volcanic plume conditions

Author

Rose, Clémence, primary, Rissanen, Matti P., additional, Iyer, Siddharth, additional, Duplissy, Jonathan, additional, Yan, Chao, additional, Nowak, John B., additional, Colomb, Aurélie, additional, Dupuy, Régis, additional, He, Xu-Cheng, additional, Lampilahti, Janne, additional, Tham, Yee Jun, additional, Wimmer, Daniela, additional, Metzger, Jean-Marc, additional, Tulet, Pierre, additional, Brioude, Jérôme, additional, Planche, Céline, additional, Kulmala, Markku, additional, and Sellegri, Karine, additional

Published
2021
Full Text
View/download PDF

17. Supplementary material to "Investigation of several proxies to estimate sulfuric acid concentration in volcanic plume conditions"

Author

Rose, Clémence, primary, Rissanen, Matti P., additional, Iyer, Siddharth, additional, Duplissy, Jonathan, additional, Yan, Chao, additional, Nowak, John B., additional, Colomb, Aurélie, additional, Dupuy, Régis, additional, He, Xu-Cheng, additional, Lampilahti, Janne, additional, Tham, Yee Jun, additional, Wimmer, Daniela, additional, Metzger, Jean-Marc, additional, Tulet, Pierre, additional, Brioude, Jérôme, additional, Planche, Céline, additional, Kulmala, Markku, additional, and Sellegri, Karine, additional

Published
2020
Full Text
View/download PDF

18. Investigation of several proxies to estimate sulfuric acid concentration in volcanic plume conditions

Author

Rose, Clémence, primary, Rissanen, Matti P., additional, Iyer, Siddharth, additional, Duplissy, Jonathan, additional, Yan, Chao, additional, Nowak, John B., additional, Colomb, Aurélie, additional, Dupuy, Régis, additional, He, Xu-Cheng, additional, Lampilahti, Janne, additional, Tham, Yee Jun, additional, Wimmer, Daniela, additional, Metzger, Jean-Marc, additional, Tulet, Pierre, additional, Brioude, Jérôme, additional, Planche, Céline, additional, Kulmala, Markku, additional, and Sellegri, Karine, additional

Published
2020
Full Text
View/download PDF

19. Cézeaux-Aulnat-Opme-Puy De Dôme: a multi-site for the long-term survey of the tropospheric composition and climate change

Author

Baray, Jean-Luc, primary, Deguillaume, Laurent, additional, Colomb, Aurélie, additional, Sellegri, Karine, additional, Freney, Evelyn, additional, Rose, Clémence, additional, Van Baelen, Joël, additional, Pichon, Jean-Marc, additional, Picard, David, additional, Fréville, Patrick, additional, Bouvier, Laëtitia, additional, Ribeiro, Mickaël, additional, Amato, Pierre, additional, Banson, Sandra, additional, Bianco, Angelica, additional, Borbon, Agnès, additional, Bourcier, Lauréline, additional, Bras, Yannick, additional, Brigante, Marcello, additional, Cacault, Philippe, additional, Chauvigné, Aurélien, additional, Charbouillot, Tiffany, additional, Chaumerliac, Nadine, additional, Delort, Anne-Marie, additional, Delmotte, Marc, additional, Dupuy, Régis, additional, Farah, Antoine, additional, Febvre, Guy, additional, Flossmann, Andrea, additional, Gourbeyre, Christophe, additional, Hervier, Claude, additional, Hervo, Maxime, additional, Huret, Nathalie, additional, Joly, Muriel, additional, Kazan, Victor, additional, Lopez, Morgan, additional, Mailhot, Gilles, additional, Marinoni, Angela, additional, Masson, Olivier, additional, Montoux, Nadège, additional, Parazols, Marius, additional, Peyrin, Frédéric, additional, Pointin, Yves, additional, Ramonet, Michel, additional, Rocco, Manon, additional, Sancelme, Martine, additional, Sauvage, Stéphane, additional, Schmidt, Martina, additional, Tison, Emmanuel, additional, Vaïtilingom, Mickaël, additional, Villani, Paolo, additional, Wang, Miao, additional, Yver-Kwok, Camille, additional, and Laj, Paolo, additional

Published
2020
Full Text
View/download PDF

20. Overview of aerosol optical properties over southern West Africa from DACCIWA aircraft measurements

Author

Denjean, Cyrielle, primary, Bourrianne, Thierry, additional, Burnet, Frederic, additional, Mallet, Marc, additional, Maury, Nicolas, additional, Colomb, Aurélie, additional, Dominutti, Pamela, additional, Brito, Joel, additional, Dupuy, Régis, additional, Sellegri, Karine, additional, Schwarzenboeck, Alfons, additional, Flamant, Cyrille, additional, and Knippertz, Peter, additional

Published
2020
Full Text
View/download PDF

21. Remote biomass burning dominates southern West African air pollution during the monsoon

Author

Haslett, Sophie L., primary, Taylor, Jonathan W., additional, Evans, Mathew, additional, Morris, Eleanor, additional, Vogel, Bernhard, additional, Dajuma, Alima, additional, Brito, Joel, additional, Batenburg, Anneke M., additional, Borrmann, Stephan, additional, Schneider, Johannes, additional, Schulz, Christiane, additional, Denjean, Cyrielle, additional, Bourrianne, Thierry, additional, Knippertz, Peter, additional, Dupuy, Régis, additional, Schwarzenböck, Alfons, additional, Sauer, Daniel, additional, Flamant, Cyrille, additional, Dorsey, James, additional, Crawford, Ian, additional, and Coe, Hugh, additional

Published
2019
Full Text
View/download PDF

22. A comprehensive in situ and remote sensing data set from the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign

Author

Ehrlich, André, primary, Wendisch, Manfred, additional, Lüpkes, Christof, additional, Buschmann, Matthias, additional, Bozem, Heiko, additional, Chechin, Dmitri, additional, Clemen, Hans-Christian, additional, Dupuy, Régis, additional, Eppers, Olliver, additional, Hartmann, Jörg, additional, Herber, Andreas, additional, Jäkel, Evelyn, additional, Järvinen, Emma, additional, Jourdan, Olivier, additional, Kästner, Udo, additional, Kliesch, Leif-Leonard, additional, Köllner, Franziska, additional, Mech, Mario, additional, Mertes, Stephan, additional, Neuber, Roland, additional, Ruiz-Donoso, Elena, additional, Schnaiter, Martin, additional, Schneider, Johannes, additional, Stapf, Johannes, additional, and Zanatta, Marco, additional

Published
2019
Full Text
View/download PDF

23. Cézeaux-Aulnat-Opme-Puy De Dôme: a multi-site for the long term survey of the tropospheric composition and climate change

Author

Baray, Jean-Luc, primary, Deguillaume, Laurent, additional, Colomb, Aurélie, additional, Sellegri, Karine, additional, Freney, Evelyn, additional, Rose, Clémence, additional, Van Baelen, Joël, additional, Pichon, Jean-Marc, additional, Picard, David, additional, Fréville, Patrick, additional, Bouvier, Laetitia, additional, Ribeiro, Mickaël, additional, Amato, Pierre, additional, Banson, Sandra, additional, Bianco, Angelica, additional, Borbon, Agnès, additional, Bourcier, Laureline, additional, Bras, Yannick, additional, Brigante, Marcello, additional, Cacault, Philippe, additional, Chauvigné, Aurélien, additional, Charbouillot, Tiffany, additional, Chaumerliac, Nadine, additional, Delort, Anne Marie, additional, Delmotte, Marc, additional, Dupuy, Régis, additional, Farah, Antoine, additional, Febvre, Guy, additional, Flossmann, Andrea, additional, Gourbeyre, Christophe, additional, Hervier, Claude, additional, Hervo, Maxime, additional, Huret, Nathalie, additional, Joly, Muriel, additional, Kazan, Victor, additional, Lopez, Morgan, additional, Mailhot, Gilles, additional, Marinoni, Angela, additional, Masson, Olivier, additional, Montoux, Nadège, additional, Parazols, Marius, additional, Peyrin, Frédéric, additional, Pointin, Yves, additional, Ramonet, Michel, additional, Rocco, Manon, additional, Sancelme, Martine, additional, Sauvage, Stéphane, additional, Schmidt, Martina, additional, Tison, Emmanuel, additional, Vaïtilingom, Mickaël, additional, Villani, Paolo, additional, Wang, Miao, additional, Yver-Kwok, Camille, additional, and Laj, Paolo, additional

Published
2019
Full Text
View/download PDF

24. The radiative impact of out-of-cloud aerosol hygroscopic growth during the summer monsoon in southern West Africa

Author

Haslett, Sophie, Taylor, Jonathan, Deetz, Konrad, Vogel, Bernhard, Babić, Karmen, Kalthoff, Norbert, Wieser, Andreas, Dione, Cheikh, Lohou, Fabienne, Brito, Joel, Dupuy, Régis, Schwarzenboeck, Alfons, Coe, Hugh, School of Earth and Environmental Sciences [Manchester] (SEES), University of Manchester [Manchester], Institute of Mathematics - University of Aberdeen, University of Aberdeen, Institute for Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Physique (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de météorologie physique (LaMP), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), School of Earth, Atmospheric and Environmental Sciences [Manchester] (SEAES), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, and Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU]Sciences of the Universe [physics], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

25. The radiative impact of out-of-cloud aerosol hygroscopic growth during the summer monsoon in southern West Africa

Author

Haslett, Sophie L., Taylor, Jonathan W., Deetz, Konrad, Vogel, Bernhard, Babić, Karmen, Kalthoff, Norbert, Wieser, Andreas, Dione, Cheikh, Lohou, Fabienne, Brito, Joel, Dupuy, Régis, Schwarzenboeck, Alfons, Zieger, Paul, and Coe, Hugh

Subjects
Earth sciences, Atmospheric Science, ddc:550, food and beverages, hygroscopic growth, aerosol optical depth, West Africa, DACCIWA, humanities
Abstract

Water in the atmosphere can exist in the solid, liquid or gas phase. At high humidities, if the aerosol population remains constant, more water vapour will condense onto the particles and cause them to swell, sometimes up to several times their original size. This significant change in size and chemical composition is termed hygroscopic growth and alters a particle's optical properties. Even in unsaturated conditions, this can change the aerosol direct effect, for example by increasing the extinction of incoming sunlight. This can have an impact on a region's energy balance and affect visibility. Here, aerosol and relative humidity measurements collected from aircraft and radiosondes during the Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA) campaign were used to estimate the effect of highly humid layers of air on aerosol optical properties during the monsoon season in southern West Africa. The effects of hygroscopic growth in this region are of particular interest due to the regular occurrence of high humidity and the high levels of pollution in the region. The Zdanovskii, Stokes and Robinson (ZSR) mixing rule is used to estimate the hygroscopic growth of particles under different conditions based on chemical composition. These results are used to estimate the aerosol optical depth (AOD) at »Combining double low line525 nm for 63 relative humidity profiles. The median AOD in the region from these calculations was 0.36, the same as that measured by sun photometers at the ground site. The spread in the calculated AODs was less than the spread from the sun photometer measurements. In both cases, values above 0.5 were seen predominantly in the mornings and corresponded with high humidities. Observations of modest variations in aerosol load and composition are unable to explain the high and variable AODs observed using sun photometers, which can only be recreated by accounting for the very elevated and variable relative humidities (RHs) in the boundary layer. Most importantly, the highest AODs present in the mornings are not possible without the presence of high RH in excess of 95 %. Humid layers are found to have the most significant impact on AOD when they reach RH greater than 98 %, which can result in a wet AOD more than 1.8 times the dry AOD. Unsaturated humid layers were found to reach these high levels of RH in 37 % of observed cases. It can therefore be concluded that the high AODs present across the region are driven by the high humidities and are then moderated by changes in aerosol abundance. Aerosol concentrations in southern West Africa are projected to increase substantially in the coming years; results presented here show that the presence of highly humid layers in the region is likely to enhance the consequent effect on AOD significantly.

Published
2019

26. science polaire

Author

Wendisch, Manfred, Macke, Andreas, Ehrlich, Andre, Lüpkes, Alfred, Mech, Mario, Chechin, Alfred, Dethloff, Alfred, Barientos, Carola, Bozem, Johannes, Brückner, Stephan, Clemen, Hans-Christian, Crewell, Susanne, Donth, Stephan, Dupuy, Régis, Ebell, Kerstin, Egerer, Ulrike, Engelmann, Ronny, Engler, Stephan, Eppers, Johannes, Gehrmann, Alfred, Gong, Xianda, Gottschalk, Stephan, Gourbeyre, Christophe, Griesche, Hannes, Hartmann, Alfred, Hartmann, Markus, Heinold, Bernd, Herber, Alfred, HERRMANN, HARTMUT, Heygster, Georg, Hoor, Johannes, Jafariserajehlou, Soheila, Jäkel, Stephan, Järvinen, Emma, Jourdan, Olivier, Kästner, Udo, Kecorius, Simonas, Knudsen, Erlend, Köllner, Franziska, Kretzschmar, Stephan, Lelli, Luca, Leroy, Delphine, Maturilli, Alfred, Mei, Linlu, Mertes, Stephan, Mioche, Guillaume, Neuber, Alfred, Nicolaus, Alfred, Nomokonova, Tatiana, Notholt, Justus, Palm, Mathias, van Pinxteren, Manuela, Quaas, Johannes, Richter, Philipp, Ruiz-Donoso, Elena, Schäfer, Michael, Schmieder, Katja, Schnaiter, Martin, Schneider, Johannes, Schwarzenboeck, Alfons, Seifert, Patric, Shupe, Matthew, Siebert, Holger, Spreen, Gunnar, Stapf, Johannes, Stratmann, Frank, Vogl, Teresa, Welti, André, Wex, Heike, Wiedensohler, Alfred, Zanatta, Marco, Zeppenfeld, Sebastian, Leipziger Institut für Meteorologie (LIM), Universität Leipzig [Leipzig], Universität zu Köln, Institut für Physik der Atmosphäre [Mainz] (IPA), Johannes Gutenberg - Universität Mainz (JGU), Institut für Geophysik und Meteorologie [Köln], Laboratoire de Météorologie Physique (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Leibniz Institute for Tropospheric Research (TROPOS), Laboratoire de météorologie physique (LaMP), Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS), Institute of Environmental Physics [Bremen] (IUP), University of Bremen, Karlsruher Institut für Technologie (KIT), Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft, UMR CNRS 8179, Université de Lille, Sciences et Technologies-Centre National de la Recherche Scientifique (CNRS), Institut für Umweltphysik [Bremen] (IUP), Universität Bremen, University of Kassel, Technische Universität Darmstadt (TU Darmstadt), Laboratoire des champs magnétiques intenses (LCMI-GHMFL), Centre National de la Recherche Scientifique (CNRS), Faculty of Physics [Vienna], Universität Wien, Universidad Mayor de San Andrés (UMSA), Dipartimento di Fisica [Povo], Università degli Studi di Trento (UNITN), Universität Leipzig, Universität zu Köln = University of Cologne, Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Technische Universität Darmstadt - Technical University of Darmstadt (TU Darmstadt)

Subjects
[SDU]Sciences of the Universe [physics], [SDE.MCG]Environmental Sciences/Global Changes, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

27. Sensitivity of low-level clouds and precipitation to anthropogenic aerosol emission in southern West Africa: a DACCIWA case study.

Author

Deroubaix, Adrien, Menut, Laurent, Flamant, Cyrille, Knippertz, Peter, Fink, Andreas, Batenburg, Anneke, Brito, Joel, Denjean, Cyrielle, Dione, Cheikh, Dupuy, Régis, Hahn, Valerian, Kalthoff, Norbert, Lohou, Fabienne, Schwarzenboeck, Alfons, Siour, Guillaume, Tuccella, Paolo, and Voigt, Christiane

Abstract

During the West African summer monsoon, pollutants emitted in urbanized coastal areas modify cloud cover and precipitation patterns. The Dynamics-Aerosol-Chemistry-Cloud-Interactions in West Africa (DACCIWA) field campaign provided numerous aircraft-based and ground-based observations, which are used here to evaluate two experiments made with the coupled WRF-CHIMERE model, integrating both the direct and indirect aerosol effect on meteorology. During one well-documented week (1-7 July 2016), the impacts of anthropogenic aerosols on the diurnal cycle of low-level clouds and precipitation are analyzed in detail using high and moderate intensity of anthropogenic emissions in the experiments. Over the continent and close to major anthropogenic emission sources, the breakup time of low-level clouds is delayed by one hour, and the daily precipitation rate decreased by 7.5 % with the enhanced anthropogenic emission experiment (with high aerosol load). Despite the small modifications on daily average of low-level cloud cover (+2.6 %) with high aerosol load compared to moderate, there is an increase by more than 20 % from 14:00 to 22:00 UTC on hourly average. Moreover, modifications of the modeled low-level cloud and precipitation rate occur far from the major anthropogenic emission sources, to the south over the ocean and to the north up to 11° N. The present study adds evidence to recent findings that enhanced pollution levels in West Africa may reduce precipitation. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

28. New in-situ measurements of microphysical cloud properties in West Africa-Impact of aerosol on low level clouds

Author

Hahn, Valerian, Voigt, Christiane, Catoire, Valéry, Brocchi, Vanessa, Sauer, Daniel, Schlager, Hans, Stratmann, Greta, Coe, Hugh, Taylor, Jonathan, Haslett, Sophie, Brito, Joël, Scwarzenboeck, Alfons, Dupuy, Régis, Flamant, Cyrille, DLR Institut für Physik der Atmosphäre (IPA), Deutsches Zentrum für Luft- und Raumfahrt [Oberpfaffenhofen-Wessling] (DLR), Laboratoire de physique et chimie de l'environnement (LPCE), Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Centre for Atmospheric Science [Manchester] (CAS), School of Earth and Environmental Sciences [Manchester] (SEES), University of Manchester [Manchester]-University of Manchester [Manchester], University of Manchester [Manchester], Laboratoire de Météorologie Physique (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), and Dupuy, Regis

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [PHYS.PHYS.PHYS-AO-PH] Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Abstract

International audience; Southern West Africa is currently a region of major socio-economical changes. Population increases, urbanization and economic growth in this region are accompanied by increasing anthropogenic emissions of trace gases and aerosols from domestic fires, industry and biomass burning. This not only gives rise to negative health effects, but could also have an imprint on atmospheric composition and clouds, weather and climate. To examine the role of Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa, the DACCIWA campaign (Flamant et al., BAMS, 2017) took place in West Africa in 2016, combining aircraft and ground based measurements, satellite remote sensing, as well as weather and climate modeling activities. During the aircraft campaign in June and July 2016 the three research aircraft the DLR Falcon, the SAFIRE ATR 42 and the BAS Twin Otter were based in Lomé (Togo) and performed measurements of cloud properties, aerosols and trace gases over a region for which thus far only very little atmospheric in-situ data is available. Here we report on new in-situ measurements of trace gases (CO), aerosol and microphysical cloud properties (concentration and size) over Côte d'Ivoire, Ghana, Togo and Benin to investigate the aerosol effect on low level clouds. Enhanced concentrations of CO and accumulation mode aerosol were measured within the boundary layer and the lower troposphere downwind of the major cities Lomé (Togo), Abidjan (Côte d'Ivoire) and Accra (Ghana). Continental inland measurements off the Togolese and Beninese coast show a significant contribution from the densely populated rural areas in the hinterlands to the anthropogenic emissions in that area. Those emissions affect cloud microphysical properties of low clouds. Data from the Cloud and Aerosol Spectrometer (CAS) onboard the DLR Falcon show an increase in cloud droplet number density and a decrease in cloud particle effective diameter in the polluted city and urban outflow area. This novel cloud, aerosol and trace gas data set can be used for validation and evaluation of weather prediction and climate models in the West African region.

Published
2018

29. CLOUD MICROPHYSICAL PROPERTIES OF SUMMERTIME ARCTIC STRATOCUMULUS DURING THE ACLOUD CAMPAIGN : COMPARISON WITH PREVIOUS RESULTS IN THE EUROPEAN ARCTIC

Author

Dupuy, Régis, Jourdan, O., Mioche, G., Ehrlich, A, Waitz, F, Gourbeyre, C., Järvinen, E, Schnaiter, M., Schwarzenboeck, Alfons, Laboratoire de Météorologie Physique (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de météorologie physique (LaMP), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universität Leipzig, Institute for Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), Institut für Meteorologie und Klimaforschung - Atmosphärische Aerosol Forschung (IMK-AAF), Karlsruher Institut für Technologie (KIT), Dupuy, Regis, Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS), and Universität Leipzig [Leipzig]

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

30. Light absorption properties of aerosols over Southern West Africa

Author

Denjean, Cyrielle, primary, Bourrianne, Thierry, additional, Burnet, Frederic, additional, Mallet, Marc, additional, Maury, Nicolas, additional, Colomb, Aurélie, additional, Dominutti, Pamela, additional, Brito, Joel, additional, Dupuy, Régis, additional, Sellegri, Karine, additional, Schwarzenboeck, Alfons, additional, Flamant, Cyrille, additional, and Knippertz, Peter, additional

Published
2019
Full Text
View/download PDF

31. Aerosol influences on low-level clouds in the West African monsoon

Author

Taylor, Jonathan W., primary, Haslett, Sophie L., additional, Bower, Keith, additional, Flynn, Michael, additional, Crawford, Ian, additional, Dorsey, James, additional, Choularton, Tom, additional, Connolly, Paul J., additional, Hahn, Valerian, additional, Voigt, Christiane, additional, Sauer, Daniel, additional, Dupuy, Régis, additional, Brito, Joel, additional, Schwarzenboeck, Alfons, additional, Bourriane, Thierry, additional, Denjean, Cyrielle, additional, Rosenberg, Phil, additional, Flamant, Cyrille, additional, Lee, James D., additional, Vaughan, Adam R., additional, Hill, Peter G., additional, Brooks, Barbara, additional, Catoire, Valéry, additional, Knippertz, Peter, additional, and Coe, Hugh, additional

Published
2019
Full Text
View/download PDF

33. The radiative impact of out-of-cloud aerosol hygroscopic growth during the summer monsoon in southern West Africa

Author

Haslett, Sophie L., primary, Taylor, Jonathan W., additional, Deetz, Konrad, additional, Vogel, Bernhard, additional, Babić, Karmen, additional, Kalthoff, Norbert, additional, Wieser, Andreas, additional, Dione, Cheikh, additional, Lohou, Fabienne, additional, Brito, Joel, additional, Dupuy, Régis, additional, Schwarzenboeck, Alfons, additional, Zieger, Paul, additional, and Coe, Hugh, additional

Published
2019
Full Text
View/download PDF

36. Impact of long-range transport pollution on aerosol properties over West Africa: observations during the DACCIWA airborne campaign

Author

Denjean, Cyrielle, Bourrianne, Thierry, Burnet, Frédéric, Deroubaix, Adrien, Brito, Joel, Dupuy, Régis, Colomb, Aurélie, Schwarzenboeck, Alfons, Sellegri, Karine, Chazette, Patrick, Duplissy, Jonathan, Flamant, Cyrille, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire de Météorologie Physique (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Department of Physics [Helsinki], Falculty of Science [Helsinki], University of Helsinki-University of Helsinki, TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, and Météo France-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDE]Environmental Sciences
Abstract

International audience; Southern West Africa (SWA) is a region highly vulnerable to climate change. Emissions of anthropogenic pollution have increased substantially over the past decades in the region and are projected to keep increasing. The region is also strongly impacted by important natural pollution from distant locations. Biomass burning mainly from vegetation fires in Central Africa and mineral dust from the Saharan and Sahel-Sudan regions are advected by winds to the SWA region especially in summer. Both biomass burning and mineral dust aerosols scatter and absorb solar radiation and are able to significantly modify the regional radiative budget. Presently, the potential radiative impact of dust and biomass burning particles on SWA is unclear due to inadequate data information on the aerosols properties and vertical distribution. In the framework of the Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA) project, an unprecedented field campaign took place in summer 2016 in West Africa. The ATR-42 research aircraft operated by SAFIRE performed twenty flights to sample the local air pollution from maritime traffic and coastal megacities, as well as regional pollution from biomass burning and desert dust. The aircraft was equipped with state of the art in situ instrumentation to measure the aerosol optical properties (CAPS, nephelometer, PSAP), the aerosol size distribution (SMPS, GRIMM, USHAS, PCASP, FSSP) and the aerosol chemical composition (SP2, AMS). A mini backscattered lidar system provided additional measurements of the aerosol vertical structure and the aerosol optical properties such as the particulate depolarization ratio. The CHIMERE chemistry and transport model has been used to characterize the source area and the long-range transport of dust and biomass burning plumes. Here, we investigate the aerosol microphysical, chemical and optical properties of biomass burning and dust aerosols transported in SWA. In particular the following questions will be addressed: (i) what are the differences in the aerosol optical properties and vertical distribution in SWA during intense biomass burning and dust events ? (ii) what is the range of mass extinction efficiencies and single scattering albedo for these events and what explains their variability ? (iii) what is the range in aerosol size distribution in biomass burning and dust layers and how does this vary with plume age ?

Published
2017

37. Vertical distribution of microphysical properties of Arctic springtime low-level mixed-phase clouds over the Greenland and Norwegian seas

Author

Mioche, Guillaume, Jourdan, Olivier, Delanoë, Julien, Gourbeyre, Christophe, Febvre, Guy, Dupuy, Régis, Monier, Marie, Szczap, Frédéric, Schwarzenboeck, Alfons, Gayet, Jean-François, Laboratoire de Météorologie Physique (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), SPACE - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and CNRS/INSU

Subjects
[SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology
Abstract

International audience; This study aims to characterize the microphysical and optical properties of ice crystals and supercooled liquid droplets within low-level Arctic mixed-phase clouds (MPCs). We compiled and analyzed cloud in situ measurements from four airborne spring campaigns (representing 18 flights and 71 vertical profiles in MPCs) over the Greenland and Norwegian seas mainly in the vicinity of the Svalbard archipelago. Cloud phase discrimination and representative vertical profiles of the number, size, mass and shape of ice crystals and liquid droplets are established. The results show that the liquid phase dominates the upper part of the MPCs. High concentrations (120 cm−3 on average) of small droplets (mean values of 15 µm), with an averaged liquid water content (LWC) of 0.2 g m−3 are measured at cloud top. The ice phase dominates the microphysical properties in the lower part of the cloud and beneath it in the precipitation region (mean values of 100 µm, 3 L−1 and 0.025 g m−3 for diameter, particle concentration and ice water content (IWC), respectively). The analysis of the ice crystal morphology shows that the majority of ice particles are irregularly shaped or rimed particles; the prevailing regular habits found are stellars and plates. We hypothesize that riming and diffusional growth processes, including the Wegener–Bergeron–Findeisen (WBF) mechanism, are the main growth mechanisms involved in the observed MPCs. The impact of larger-scale meteorological conditions on the vertical profiles of MPC properties was also investigated. Large values of LWC and high concentration of smaller droplets are possibly linked to polluted situations and air mass origins from the south, which can lead to very low values of ice crystal size and IWC. On the contrary, clean situations with low temperatures exhibit larger values of ice crystal size and IWC. Several parameterizations relevant for remote sensing or modeling studies are also determined, such as IWC (and LWC) – extinction relationship, ice and liquid integrated water paths, ice concentration and liquid water fraction according to temperature.

Published
2017

38. Investigation of several proxies to estimate sulfuric acid concentration in volcanic plume conditions.

Author

Rose, Clémence, Rissanen, Matti P., Iyer, Siddharth, Duplissy, Jonathan, Yan, Chao, Nowak, John B., Colomb, Aurélie, Dupuy, Régis, He, Xu-Cheng, Lampilahti, Janne, Tham, Yee Jun, Wimmer, Daniela, Metzger, Jean-Marc, Tulet, Pierre, Brioude, Jérôme, Planche, Céline, Kulmala, Markku, and Sellegri, Karine

Abstract

Sulfuric acid (H2SO4) is commonly accepted as a key precursor for atmospheric new particle formation (NPF). However, direct measurements of [H2SO4] remain challenging, thus preventing the determination of this important quantity, and, consequently, a complete understanding of its contribution to the NPF process. Several proxies have been developed to bridge the gaps, but their ability to predict [H2SO4] in very specific conditions such as those encountered in volcanic plumes (including in particular high sulphur dioxide mixing ratios) has not been evaluated so far. In this context, the main objective of the present study was to develop new proxies for daytime [H2SO4] in volcanic plume conditions and compare their performance to that of the proxies available in the literature. In specific, the data collected at Maïdo during the OCTAVE 2018 campaign, in the volcanic eruption plume of the Piton de la Fournaise, were first used to derive seven proxies based on the knowledge of sulphur dioxide (SO2) mixing ratio, global radiation, condensation sink (CS) and relative humidity (RH). In three of the seven proxies (F1-F3), all variables were given equal weight in the prediction of [H2SO4], while adjusted powers were allowed for the different variables in the other four proxies (A1-A4). Proxies A1-A4 were overall found to perform better compared to F1-F3, with, in specific, improved predictive ability for [H2SO4] > 2×108 cm-3. The CS was observed to play an important role in regulating [H2SO4], while, in contrast, the inclusion of RH did not improve the predictions. A last expression accounting for an additional sink term related to cluster formation, S1, was also tested and showed a very good predictive ability over the whole range of measured [H2SO4]. The newly developed proxies were in a second step further evaluated using airborne measurements performed in the passive degassing plume of Etna during the STRAP 2016 campaign. Increased correlations between observed and predicted [H2SO4] were obtained when the dependence of predicted [H2SO4] over CS was the lowest, and when the dependence over [SO2] was concurrently the highest. The best predictions were finally retrieved by the simple formulation of F2 (in which [SO2] and radiation alone were assumed to explain the variations of [H2SO4] with equal contributions), with a pre factor adapted to the STRAP data. All in all, our results illustrate the fairly good capacity of the proxy available in the literature to describe [H2SO4] in volcanic plume conditions, but highlight at the same time the benefit of the newly developed proxies for the prediction of the highest concentrations ([H2SO4] > 2-3×108 cm-3). Also, the contrasting behaviours of the new proxies in the two investigated datasets indicate that in volcanic plumes like in other environments, the relevance of a proxy can be affected by changes in environmental conditions, and that location specific coefficients do logically improve the predictions. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

39. Aerosol composition and the contribution of SOA formation over Mediterranean forests

Author

Freney, Evelyn, primary, Sellegri, Karine, additional, Chrit, Mounir, additional, Adachi, Kouji, additional, Brito, Joel, additional, Waked, Antoine, additional, Borbon, Agnès, additional, Colomb, Aurélie, additional, Dupuy, Régis, additional, Pichon, Jean-Marc, additional, Bouvier, Laetitia, additional, Delon, Claire, additional, Jambert, Corinne, additional, Durand, Pierre, additional, Bourianne, Thierry, additional, Gaimoz, Cécile, additional, Triquet, Sylvain, additional, Féron, Anaïs, additional, Beekmann, Matthias, additional, Dulac, François, additional, and Sartelet, Karine, additional

Published
2018
Full Text
View/download PDF

40. Characterization of the cloud microphysical and optical properties and aerosol-cloud interaction in the Arctic from in situ ground-based measurements during the CLIMSLIP-NyA campaign, Svalbard

Author

Guyot, Gwennolé, primary, Olofson, Frans, additional, Tunved, Peter, additional, Gourbeyre, Christophe, additional, Fevbre, Guy, additional, Dupuy, Régis, additional, Bernard, Christophe, additional, Ancellet, Gérard, additional, Law, Kathy, additional, Quennehen, Boris, additional, Schwarzenboeck, Alfons, additional, Eleftheriadis, Kostas, additional, and Jourdan, Olivier, additional

Published
2017
Full Text
View/download PDF

41. Ground based in situ measurements of arctic cloud microphysical and optical properties at Mount Zeppelin, Svalbard

Author

Guyot, Gwennolé, Jourdan, Olivier, Olofson, Frans, Schwarzenboeck, Alfons, Gourbeyre, Christophe, Febvre, Guy, Dupuy, Régis, Bernard, Christophe, Tunved, Peter, Ancellet, Gérard, Law, Kathy S., Wobrock, Wolfram, Shcherbakov, Valery, Laboratoire de météorologie physique (LaMP), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Department of Environmental Science and Analytical Chemistry [Stockholm] (ACES), Stockholm University, TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
[SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology
Abstract

International audience; Climate simulations suggest that cloud feedback plays an important role in the arctic warming. Moreover, the high seasonal variability of arctic aerosol properties is expected to significantly impact the cloud properties during the winter-summer transition. Field measurements are needed for improved understanding and representation of cloud-aerosol interactions in climate models.Within the CLIMSLIP project (CLimate IMpacts of Short-LIved Pollutants and methane in the arctic), a two months (March-April 2012) ground-based cloud measurement campaign was performed at Mt Zeppelin station, Ny-Alesund, Svalbard. The experimental set-up comprised a wide variety of instruments. A CPI (Cloud Particle Imager) was used for the microphysical and morphological characterization of ice particles. Measurements of sized-resolved liquid cloud parameters were performed by the FSSP-100 (Forward Scattering Spectrometer Probe). The Nevzorov Probe measured the bulk properties of clouds. The Polar Nephelometer was used to assess the single scattering properties of an ensemble of cloud particles. This cloud instrumentation combined with the aerosol properties continuously measured at the station allowed us to study the variability of the microphysical and optical properties of low level Mixed Phase Clouds (MPC) as well as the aerosol- cloud interaction in the Arctic. Typical properties of MPC, snow precipitation and blowing snow will be presented. First results suggest that liquid water is ubiquitous in spring arctic low level clouds. Carbon monoxide measurements allow us to compare polluted with clean cases. The cloud-aerosol interactions processes which take place during the transport of polluted air masses from mid-latitude to the Arctic is thus assessed.

Published
2016

42. Characterization of Arctic mixed phase clouds at regional and small scales

Author

Jourdan, Olivier, Mioche, Guillaume, Delanoë, Julien, Gourbeyre, Christophe, Dupuy, Régis, Schwarzenboeck, Alfons, Laboratoire de météorologie physique (LaMP), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), SPACE - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Abstract

International audience; Previous observations suggest that Mixed Phase Clouds (MPC) occur frequently in the Arctic and often persist for many days due to a combination of local processes (microphysical and radiative for instance) and larger scale meteorological conditions. These low-level liquid containing clouds exert a large influence on the surface radiative fluxes and feedbacks on Arctic climate. However, understanding the spatial phase distribution within MPC remains a challenge.In this study, the MPC macrophysical and microphysical properties are investigated at a regional scale using CloudSat and CALIPSO observations (2007-2010) and at smaller scale with airborne in situ measurements performed in the Svalbard region.Results show that MPCs have a mean frequency of occurrence ranging from 30% (end of winter) to 55% (in autumn) in the Arctic. In the Svalbard region, the frequencies of occurrence are significantly higher with values ranging from 45% to 60%. MPCs are especially located at low altitudes, below 3000m, where their occurrence reaches 90%, particularly in winter, spring and autumn. Moreover, results highlight that MPCs are statistically more frequent over open sea than sea ice or land. These observations also allow us to assess how already performed small scale airborne measurements are representative of the variety of clouds encountered in the Arctic. In situ measurements (44 vertical profiles obtained during ASTAR, POLARCAT, SORPIC) are statistically analyzed to derive representative profiles of MPC microphysical and optical properties (optical depth, liquid/water fraction, ice crystals habit). These analyses should contribute to a better understanding of processes occurring in arctic MPC.

Published
2016

43. Supplementary material to "Aerosol composition and the contribution of SOA formation over Mediterranean forests"

Author

Freney, Evelyn, primary, Sellegri, Karine, additional, Chrit, Mounir, additional, Adachi, Kouji, additional, Brito, Joel, additional, Waked, Antoine, additional, Borbon, Agnès, additional, Colomb, Aurélie, additional, Dupuy, Régis, additional, Pichon, Jean-Marc, additional, Bouvier, Laetitia, additional, Delon, Claire, additional, Jambert, Corinne, additional, Durand, Pierre, additional, Bourianne, Thierry, additional, Gaimoz, Cécile, additional, Triquet, Sylvain, additional, Féron, Anaïs, additional, Beekmann, Matthias, additional, Dulac, François, additional, and Sartelet, Karine, additional

Published
2017
Full Text
View/download PDF

44. Aerosol composition and the contribution of SOA formation over Mediterranean forests

Author

Freney, Evelyn, primary, Sellegri, Karine, additional, Chrit, Mounir, additional, Adachi, Kouji, additional, Brito, Joel, additional, Waked, Antoine, additional, Borbon, Agnès, additional, Colomb, Aurélie, additional, Dupuy, Régis, additional, Pichon, Jean-Marc, additional, Bouvier, Laetitia, additional, Delon, Claire, additional, Jambert, Corinne, additional, Durand, Pierre, additional, Bourianne, Thierry, additional, Gaimoz, Cécile, additional, Triquet, Sylvain, additional, Féron, Anaïs, additional, Beekmann, Matthias, additional, Dulac, François, additional, and Sartelet, Karine, additional

Published
2017
Full Text
View/download PDF

46. Ground based in situ measurements of arctic cloud microphysical and optical properties at Mount Zeppelin (Ny-Alesund Svalbard)

Author

Guyot, Gwennolé, Jourdan, Olivier, Olofson, Frans, Schwarzenboeck, Alfons, Gourbeyre, Christophe, Febvre, Guy, Dupuy, Régis, Bernard, Christophe, Tunved, Peter, Ancellet, Gérard, Law, Kathy S., Wobrock, Wolfram, Shcherbakov, Valery, Laboratoire de météorologie physique (LaMP), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Statistics and Actuarial Science [Toronto], University of Waterloo [Waterloo], Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institute for Applied Environmental Research [Stockholm], Stockholm University, TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS), and Cardon, Catherine

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [SDU.STU.CL] Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [PHYS.PHYS.PHYS-AO-PH] Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Abstract

International audience; The high sensitivity of the polar regions to climate perturbation, due to complex feedback mechanisms existing in this region, was shown by many studies (Solomon et al., 2007; Verlinde et al., 2007; IPCC, 2007). In particular, climate simulations suggest that cloud feedback plays an important role in the arctic warming (Vavrus 2004; Hassol, 2005). Moreover, the high seasonal variability of arctic aerosol properties (Engwall et al., 2008; Tunveld et al., 2013) is expected to significantly impact the cloud properties during the winter-summer transition. Field measurements are needed for improved understanding and representation of cloud-aerosol interactions in climate models. Within the CLIMSLIP project (CLimate IMpacts of Short-LIved Pollutants and methane in the arctic), a two months (March-April 2012) ground-based cloud measurement campaign was performed at Mt Zeppelin station, Ny-Alesund, Svalbard. The experimental setup comprised a wide variety of instruments. A CPI (Cloud Particle Imager) was used for the microphysical and morphological characterization of ice particles. Measurements of sized-resolved liquid cloud parameters were performed by the FSSP-100 (Forward Scattering Spectrometer Probe). The Nevzorov Probe measured the bulk properties (LWC and IWC) of clouds. The Polar Nephelometer (PN) was used to assess the single scattering properties of an ensemble of cloud particles. This cloud instrumenta-tion combined with the aerosol properties (size distribution and total concentration) continuously measured at the station allowed us to study the variability of the microphysical and optical properties of low level Mixed Phase Clouds (MPC) as well as the aerosol-cloud interaction in the Arctic. Typical properties of MPC, snow precipitation and blowing snow will be presented. First results suggest that liquid water is ubiquitous in arctic low level clouds. Precipitations are characterized by large (typically 1 mm sized) stellar and pristine shape particles whereas blowing snow is typically composed of 250 µm irregular ice crystals. This dataset will be used to test physically based representations of the relationships between particle size, shape and optical properties and to investigate dominant microphysical processes occurring in MPC using detailed microphysical modeling. Moreover, carbon monoxide measurements allow us to compare polluted with clean cases. The cloud-aerosol interactions processes which take place during the transport of polluted air masses from mid-latitude to the Arctic is thus assessed.

Published
2015

47. Light absorption properties of aerosols over Southern West Africa.

Author

Denjean, Cyrielle, Bourrianne, Thierry, Burnet, Frederic, Mallet, Marc, Maury, Nicolas, Colomb, Aurélie, Dominutti, Pamela, Brito, Joel, Dupuy, Régis, Sellegri, Karine, Schwarzenboeck, Alfons, Flamant, Cyrille, and Knippertz, Peter

Abstract

Southern West Africa (SWA) is an African pollution hotspot but a relatively poorly sampled region of the world. We present an overview of in-situ aerosol optical measurements collected over SWA in June and July 2016 as part as the DACCIWA (Dynamics-Aerosol-Chemistry-Clouds Interactions in West Africa) airborne campaign. The aircraft sampled a wide range of air masses, including anthropogenic pollution plumes emitted from the coastal cities, long-range transported biomass burning plumes from Central and Southern Africa and dust plumes from the Sahara and Sahel region, as well as mixtures of these plumes. The specific objective of this work is to characterize the regional variability of the vertical distribution of aerosol particles and their spectral optical properties (single scattering albedo: SSA, asymmetry parameter, extinction mass efficiency, scattering Ångström exponent and absorption Ångström exponent: AAE). First findings indicate that aerosol optical properties in the planetary boundary layer were dominated by a widespread and persistent biomass burning loading from the Southern Hemisphere. Despite a strong increase of aerosol number concentration in air masses downwind of urban conglomerations, spectral SSA were comparable to the background and showed signatures of the absorption characteristics of biomass burning aerosols. In the free troposphere, moderately to strongly absorbing aerosol layers, dominated by either dust or biomass burning particles, occurred occasionally. In aerosol layers dominated by mineral dust particles, SSA varied from 0.81 to 0.92 at 550 nm depending on the variable proportion of anthropogenic pollution particles externally mixed with the dust. Biomass burning aerosol particles were significantly more light absorbing than those previously measured in other areas (e.g. Amazonia, North America) with SSA ranging from 0.71 to 0.77 at 550 nm. The variability of SSA was mainly controlled by variations in aerosol composition rather than in aerosol size distribution. Correspondingly, values of AAE ranged from 0.9 to 1.1, suggesting that lens-coated black carbon particles were the dominant absorber in the visible range for these biomass burning aerosols. Comparison with literature shows a consistent picture of increasing absorption enhancement of biomass burning aerosol from emission to remote location and underscores that the evolution of SSA occurred a long time after emission. The results presented here build a fundamental basis of knowledge about the aerosol optical properties observed over SWA during the monsoon season and can be used in climate modelling studies and satellite retrievals. In particular and regarding the very high absorbing properties of biomass burning aerosols over SWA, our findings suggest that considering the effect of internal mixing on absorption properties of black carbon particles in climate models should help better assessing the direct and semi-direct radiative effects of biomass burning particles. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

48. Study of the diffraction pattern of cloud particles and respective response of Optical Array Probes.

Author

de Guélis, Thibault Vaillant, Schwarzenböck, Alfons, Shcherbakov, Valery, Gourbeyre, Christophe, Laurent, Bastien, Dupuy, Régis, Coutris, Pierre, and Duroure, Christophe

Subjects
OPTICAL arrays, METEOROLOGICAL precipitation
Abstract

Optical array probes (OAPs) are classical instrumental means to derive shape, size, and number concentration of cloud and precipitation particles from 2D images. However, recorded 2D images are subject to distortion based on the diffraction of light when particles are imaged out of the object plane of the optical device. This phenomenon highly affects retrievals of microphysical properties of cloud particles. Previous studies of this effect mainly focused on spherical droplets. In this study we propose a theoretical method to compute diffraction pattern of all kind of cloud particle shapes in order to simulate the response recorded by an OAP. To check the validity of this method, a series of experimental measurements have been performed with a 2D-S probe mounted on a test bench. Measurements are performed using spinning glass discs with imprinted non-circular opaque particle shapes. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

49. Arctic mixed phase clouds properties based on airborne in situ and remote sensing measurements

Author

Mioche, Guillaume, Jourdan, Olivier, Szczap, Frédéric, Guyot, Gwennolé, Gourbeyre, Christophe, Dupuy, Régis, Delanoë, Julien, Schwarzenboeck, Alfons, Laboratoire de météorologie physique (LaMP), Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS), SPACE - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Cardon, Catherine

Subjects
[SDE.MCG] Environmental Sciences/Global Changes, [SDU.STU.CL] Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDE.MCG]Environmental Sciences/Global Changes
Abstract

Clouds radiation feedback processes in Polar Regions have been identified as key uncertainties in the prediction of global climate in GCMs. To better understand clouds-radiation interactions in these regions, knowledge of arctic clouds properties has to be improved. In particular, mixed phased clouds, which frequently occur in Arctic, present a large variety of physical characteristics and involve very complex microphysical and dynamical processes between liquid and ice phases, currently not yet well understood, and poorly documented. In order to improve the knowledge of arctic clouds properties, the Laboratoire de Météorologie Physique (LaMP) is involved from several years in several airborne measurement campaigns dedicated to the study of arctic clouds (ASTAR 2004, ASTAR 2007, POLARCAT 2008, SORPIC 2010), providing optical and microphysical in situ measurements from a unique combination of airborne probes (CPI, Polar néphélomètre, PMS FFS-100, 2D-S, Nevzorov...). Furthermore, the airborne radar/lidar system RALI from LATMOS will provide in addition active remote sensing measurements. This study will present a statistical analysis of arctic mixed phase clouds optical and microphysical properties based on these in situ measurements, representing more than 40 flights. The first main objective of this study is to investigate the ice particles and clouds droplets growth processes into the clouds, and their interaction with radiation. The second main objective is to provide accurate profiles of relevant clouds parameters to contribute to the improvement of clouds representation in global and mesoscale models and to improve airborne and spatial remote sensing retrievals algorithms (CALIPSO, CloudSat, EarthCare...). These relevant parameters are for example the thermodynamic phase, geometrical characteristics (height, thickness), and optical and microphysical properties (asymmetry parameters, optical depth, liquid/water fraction, ice crystals morphology, size and concentration, IWC...).

Published
2013

50. Characterization of the cloud microphysical and optical properties and aerosol-cloud interaction in the Arctic from in situ ground-based measurements during the CLIMSLIP-NyA campaign, Svalbard.

Author

Guyot, Gwennolé, Olofson, Frans, Tunved, Peter, Gourbeyre, Christophe, Fevbre, Guy, Dupuy, Régis, Bernard, Christophe, Ancellet, Gérard, Law, Kathy, Quennehen, Boris, Schwarzenboeck, Alfons, Eleftheriadis, Kostas, and Jourdan, Olivier

Abstract

This study will focus on cloud microphysical and optical characterization of three different types of episodes encountered during the ground based CLIMSLIP-NyA campaign performed in Ny-Alesund, Svalbard: the Mixed Phase Cloud (MPC), snow precipitation and Blowing Snow (BS) events. These in situ cloud measurements will be combined with aerosol measurements and air mass backtrajectory simulations to qualify and parameterize the arctic aerosol cloud interaction and to assess the influence of anthropogenic pollution transported into the Arctic. The results show a cloud bimodal distribution with the droplet mode at 10 μm and the crystal mode centered at 250 μm, for the MPC cases. The precipitation cases presents a crystal distribution centered around 350 μm with mostly of dendritic shape. The BS cases show a higher concentration but smaller crystals, centered between 150 and 200 μm, with mainly irregular crystals. A polluted case, where aerosol properties are influenced by anthropogenic emission from Europe and East Asia, was compared to a clean case with local aerosol sources. These anthropogenic emissions seem to cause higher Black Carbon, aerosol and droplet concentrations, a more pronounced accumulation mode, smaller droplet sizes and a higher activation fraction Fa. Moreover, the activation diameter decreases as the droplet diameter increases and Fa increases showing that smaller particles are activated and droplets grow when the aerosol number decreases. This is in agreement with the first (Twomey) and second (Albrecht) aerosol indirect effect. The quantification of the variations of droplet concentration and size leads to IE (Indirect Effect) and NE (Nucleation Efficiency) coefficients values around 0.2 and 0.43, respectively. These values are close to those found by other studies in the arctic region which confirms these parameterizations of arctic aerosol-cloud interaction in climate models. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results