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1. Cyclogenesis in the Tropical Atlantic: First Scientific Highlights from the Clouds–Atmospheric Dynamics–Dust Interactions in West Africa (CADDIWA) Field Campaign

Author

Flamant, Cyrille, primary, Chaboureau, Jean-Pierre, additional, Delanoë, Julien, additional, Gaetani, Marco, additional, Jamet, Cédric, additional, Lavaysse, Christophe, additional, Bock, Olivier, additional, Borne, Maurus, additional, Cazenave, Quitterie, additional, Coutris, Pierre, additional, Cuesta, Juan, additional, Menut, Laurent, additional, Aubry, Clémantyne, additional, Benedetti, Angela, additional, Bosser, Pierre, additional, Bounissou, Sophie, additional, Caudoux, Christophe, additional, Collomb, Hélène, additional, Donal, Thomas, additional, Febvre, Guy, additional, Fehr, Thorsten, additional, Fink, Andreas H., additional, Formenti, Paola, additional, Araujo, Nicolau Gomes, additional, Knippertz, Peter, additional, Lecuyer, Eric, additional, Andrade, Mateus Neves, additional, Langué, Cédric Gacial Ngoungué, additional, Jonville, Tanguy, additional, Schwarzenboeck, Alfons, additional, and Takeishi, Azusa, additional

Published
2024
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2. ICE GENESIS: Synergetic Aircraft and Ground-Based Remote Sensing and In Situ Measurements of Snowfall Microphysical Properties

Author

Billault-Roux, Anne-Claire, Grazioli, Jacopo, Delanoë, Julien, Jorquera, Susana, Pauwels, Nicolas, Viltard, Nicolas, Martini, Audrey, Mariage, Vincent, Le Gac, Christophe, Caudoux, Christophe, Aubry, Clémantyne, Bertrand, Fabrice, Schwarzenboeck, Alfons, Jaffeux, Louis, Coutris, Pierre, Febvre, Guy, Pichon, Jean Marc, Dezitter, Fabien, Gehring, Josué, Untersee, Aude, Calas, Christophe, Figueras I Ventura, Jordi, Vie, Benoit, Peyrat, Adrien, Curat, Valentin, Rebouissoux, Simon, Berne, Alexis, Environmental Remote Sensing Laboratory [Lausanne], Ecole Polytechnique Fédérale de Lausanne (EPFL), SPACE - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), DLR Institut für Physik der Atmosphäre (IPA), Deutsches Zentrum für Luft- und Raumfahrt [Oberpfaffenhofen-Wessling] (DLR), Laboratoire de Météorologie Physique (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Airbus Helicopters, Aeroport International de Marseille-Provence, Federal Office of Meteorology and Climatology MeteoSwiss, and Météo-France

Subjects
Snowfall, Atmospheric Science, Cloud microphysics, Precipitation, Radars/Radar observations, Remote sensing, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, Icing
Abstract

An international field experiment took place in the Swiss Jura in January 2021 as a milestone of the European ICE GENESIS project (www.ice-genesis.eu/), which aims to better measure, understand, and model the ice/snow particle properties and mechanisms responsible for icing of rotor-craft and aircraft. The field campaign was designed to collect observations of clouds and snowfall at a prescribed range of temperatures (−10° to +2°C). The suite of in situ and remote sensing instruments included airborne probes and imagers on board a SAFIRE ATR-42 aircraft, able to sample liquid and ice particles from the micron to the millimeter size range, as well as icing sensors and cameras. Two 95 GHz Doppler cloud radars were installed on the SAFIRE ATR-42, while six Doppler weather radars operating at frequencies ranging from 10 to 95 GHz (and one lidar) were ground based. An operational polarimetric weather radar in nearby France (Montancy) complements the coverage. Finally, observations of standard meteorological variables as well as high-resolution pictures of falling snowflakes from a multiangle snowflake camera were collected at the ground level. The campaign showed its full potential during five (multihourly) flights where precipitation was monitored from cloud to ground. The originality of this campaign resides in the targeted specific temperature range for snowfall and in the synchronization between the ground-based remote sensing and the aircraft trajectories designed to maximize the collection of in situ observations within the column above the radar systems.

Published
2023

3. Ice crystal images from optical array probes: classification with convolutional neural networks

Author

Jaffeux, Louis, Schwarzenböck, Alfons, Coutris, Pierre, Duroure, Christophe, Laboratoire de Météorologie Physique (LaMP), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)

Subjects
Atmospheric Science, [SDU]Sciences of the Universe [physics]
Abstract

Although airborne optical array probes (OAPs) have existed for decades, our ability to maximize extraction of meaningful morphological information from the images produced by these probes has been limited by the lack of automatic, unbiased, and reliable classification tools. The present study describes a methodology for automatic ice crystal recognition using innovative machine learning. Convolutional neural networks (CNNs) have recently been perfected for computer vision and have been chosen as the method to achieve the best results together with the use of finely tuned dropout layers. For the purposes of this study, The CNN has been adapted for the Precipitation Imaging Probe (PIP) and the 2DS Stereo Probe (2DS), two commonly used probes that differ in pixel resolution and measurable maximum size range for hydrometeors. Six morphological crystal classes have been defined for the PIP and eight crystal classes and an artifact class for the 2DS. The PIP and 2DS classifications have five common classes. In total more than 8000 images from both instruments have been manually labeled, thus allowing for the initial training. For each probe the classification design tries to account for the three primary ice crystal growth processes: vapor deposition, riming, and aggregation. We included classes such as fragile aggregates and rimed aggregates with high intra-class shape variability that are commonly found in convective clouds. The trained network is finally tested through human random inspections of actual data to show its real performance in comparison to what humans can achieve.

Published
2022

4. Water isotopic characterisation of the cloud–circulation coupling in the North Atlantic trades – Part 1: A process-oriented evaluation of COSMOiso simulations with EUREC4A observations.

Author

Villiger, Leonie, Dütsch, Marina, Bony, Sandrine, Lothon, Marie, Pfahl, Stephan, Wernli, Heini, Brilouet, Pierre-Etienne, Chazette, Patrick, Coutris, Pierre, Delanoë, Julien, Flamant, Cyrille, Schwarzenboeck, Alfons, Werner, Martin, and Aemisegger, Franziska

Subjects
CUMULUS clouds, DEUTERIUM oxide, STABLE isotopes, ATMOSPHERIC circulation, RAINFALL, FIELD research, PRECIPITATION scavenging
Abstract

Naturally available, stable, and heavy water molecules such as HDO and H 218 O have a lower saturation vapour pressure than the most abundant light water molecule H 216 O; therefore, these heavy water molecules preferentially condense and rain out during cloud formation. Stable water isotope observations thus have the potential to provide information on cloud processes in the trade-wind region, in particular when combined with high-resolution model simulations. In order to evaluate this potential, nested COSMO iso (isotope-enabled Consortium for Small Scale Modelling;) simulations with explicit convection and horizontal grid spacings of 10, 5, and 1 km were carried out in this study over the tropical Atlantic for the time period of the EUREC 4 A (Elucidating the role of clouds-circulation coupling in climate;) field experiment. The comparison to airborne in situ and remote sensing observations shows that the three simulations are able to distinguish between different mesoscale cloud organisation patterns as well as between periods with comparatively high and low rain rates. Cloud fraction and liquid water content show a better agreement with aircraft observations with higher spatial resolution, because they show strong spatial variations on the scale of a few kilometres. A low-level cold-dry bias, including too depleted vapour in the subcloud and cloud layer and too enriched vapour in the free troposphere, is found in all three simulations. Furthermore, the simulated secondary isotope variable d -excess in vapour is overestimated compared to observations. Special attention is given to the cloud base level, which is the formation altitude of shallow cumulus clouds. The temporal variability of the simulated isotope variables at cloud base agrees reasonably well with observations, with correlations of the flight-to-flight data as high as 0.7 for δ2 H and d -excess. A close examination of isotopic characteristics under precipitating clouds, non-precipitating clouds, clear-sky and dry-warm patches at the altitude of cloud base shows that these different environments are represented faithfully in the model with similar frequencies of occurrence, isotope signals, and specific-humidity anomalies as found in the observations. Furthermore, it is shown that the δ2 H of cloud base vapour at the hourly timescale is mainly controlled by mesoscale transport and not by local microphysical processes, while the d -excess is mainly controlled by large-scale drivers. Overall, this evaluation of COSMO iso , including the isotopic characterisation of different cloud base environments, suggests that the simulations can be used for investigating the role of atmospheric circulations on different scales for controlling the formation of shallow cumulus clouds in the trade-wind region, as will be done in part 2 of this study. [ABSTRACT FROM AUTHOR]

Published
2023
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7. Water isotopic characterisation of the cloud-circulation coupling in the North Atlantic trades. Part 1: A process-oriented evaluation of COSMOiso simulations with EUREC4A observations

Author

Villiger, Leonie, primary, Dütsch, Marina, additional, Bony, Sandrine, additional, Lothon, Marie, additional, Pfahl, Stephan, additional, Wernli, Heini, additional, Brilouet, Pierre-Etienne, additional, Chazette, Patrick, additional, Coutris, Pierre, additional, Delanoë, Julien, additional, Flamant, Cyrille, additional, Schwarzenboeck, Alfons, additional, Werner, Martin, additional, and Aemisegger, Franziska, additional

Published
2023
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9. EUREC 4 A

Author

Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Stevens, Bjorn, Bony, Sandrine, Farrell, David, Ament, Felix, Blyth, Alan, Fairall, Christopher, Karstensen, Johannes, Quinn, Patricia K., Speich, Sabrina, Acquistapace, Claudia, Aemisegger, Franziska, Albright, Anna Lea, Bellenger, Hugo, Bodenschatz, Eberhard, Caesar, Kathy-Ann, Chewitt-Lucas, Rebecca, de Boer, Gijs, Delanoë, Julien, Denby, Leif, Ewald, Florian, Fildier, Benjamin, Forde, Marvin, George, Geet, Gross, Silke, Hagen, Martin, Hausold, Andrea, Heywood, Karen J., Hirsch, Lutz, Jacob, Marek, Jansen, Friedhelm, Kinne, Stefan, Klocke, Daniel, Kölling, Tobias, Konow, Heike, Lothon, Marie, Mohr, Wiebke, Naumann, Ann Kristin, Nuijens, Louise, Olivier, Léa, Pincus, Robert, Pöhlker, Mira, Reverdin, Gilles, Roberts, Gregory, Schnitt, Sabrina, Schulz, Hauke, Siebesma, A. Pier, Stephan, Claudia Christine, Sullivan, Peter, Touzé-Peiffer, Ludovic, Vial, Jessica, Vogel, Raphaela, Zuidema, Paquita, Alexander, Nicola, Alves, Lyndon, Arixi, Sophian, Asmath, Hamish, Bagheri, Gholamhossein, Baier, Katharina, Bailey, Adriana, Baranowski, Dariusz, Baron, Alexandre, Barrau, Sébastien, Barrett, Paul A., Batier, Frédéric, Behrendt, Andreas, Bendinger, Arne, Beucher, Florent, Bigorre, Sebastien, Blades, Edmund, Blossey, Peter, Bock, Olivier, Böing, Steven, Bosser, Pierre, Bourras, Denis, Bouruet-Aubertot, Pascale, Bower, Keith, Branellec, Pierre, Branger, Hubert, Brennek, Michal, Brewer, Alan, Brilouet, Pierre-Etienne, Brügmann, Björn, Buehler, Stefan A., Burke, Elmo, Burton, Ralph, Calmer, Radiance, Canonici, Jean-Christophe, Carton, Xavier, Cato Jr., Gregory, Charles, Jude Andre, Chazette, Patrick, Chen, Yanxu, Chilinski, Michal T., Choularton, Thomas, Chuang, Patrick, Clarke, Shamal, Coe, Hugh, Cornet, Céline, Coutris, Pierre, Couvreux, Fleur, Crewell, Susanne, Cronin, Timothy, Cui, Zhiqiang, Cuypers, Yannis, Daley, Alton, Damerell, Gillian M., Dauhut, Thibaut, Deneke, Hartwig, Desbios, Jean-Philippe, Dörner, Steffen, Donner, Sebastian, Douet, Vincent, Drushka, Kyla, Dütsch, Marina, Ehrlich, André, Emanuel, Kerry, Emmanouilidis, Alexandros, Etienne, Jean-Claude, Etienne-Leblanc, Sheryl, Faure, Ghislain, Feingold, Graham, Ferrero, Luca, Fix, Andreas, Flamant, Cyrille, Flatau, Piotr Jacek, Foltz, Gregory R., Forster, Linda, Furtuna, Iulian, Gadian, Alan, Galewsky, Joseph, Gallagher, Martin, Gallimore, Peter, Gaston, Cassandra, Gentemann, Chelle, Geyskens, Nicolas, Giez, Andreas, Gollop, John, Gouirand, Isabelle, Gourbeyre, Christophe, de Graaf, Dörte, de Groot, Geiske E., Grosz, Robert, Güttler, Johannes, Gutleben, Manuel, Hall, Kashawn, Harris, George, Helfer, Kevin C., Henze, Dean, Herbert, Calvert, Holanda, Bruna, Ibanez-Landeta, Antonio, Intrieri, Janet, Iyer, Suneil, Julien, Fabrice, Kalesse, Heike, Kazil, Jan, Kellman, Alexander, Kidane, Abiel T., Kirchner, Ulrike, Klingebiel, Marcus, Körner, Mareike, Kremper, Leslie Ann, Kretzschmar, Jan, Krüger, Ovid, Kumala, Wojciech, Kurz, Armin, L'Hégaret, Pierre, Labaste, Matthieu, Lachlan-Cope, Tom, Laing, Arlene, Landschützer, Peter, Lang, Theresa, Lange, Diego, Lange, Ingo, Laplace, Clément, Lavik, Gauke, Laxenaire, Rémi, Le Bihan, Caroline, Leandro, Mason, Lefevre, Nathalie, Lena, Marius, Lenschow, Donald, Li, Qiang, Lloyd, Gary, Los, Sebastian, Losi, Niccolò, Lovell, Oscar, Luneau, Christopher, Makuch, Przemyslaw, Malinowski, Szymon, Manta, Gaston, Marinou, Eleni, Marsden, Nicholas, Masson, Sebastien, Maury, Nicolas, Mayer, Bernhard, Mayers-Als, Margarette, Mazel, Christophe, McGeary, Wayne, McWilliams, James C., Mech, Mario, Mehlmann, Melina, Meroni, Agostino Niyonkuru, Mieslinger, Theresa, Minikin, Andreas, Minnett, Peter, Möller, Gregor, Morfa Avalos, Yanmichel, Muller, Caroline, Musat, Ionela, Napoli, Anna, Neuberger, Almuth, Noisel, Christophe, Noone, David, Nordsiek, Freja, Nowak, Jakub L., Oswald, Lothar, Parker, Douglas J., Peck, Carolyn, Person, Renaud, Philippi, Miriam, Plueddemann, Albert, Pöhlker, Christopher, Pörtge, Veronika, Pöschl, Ulrich, Pologne, Lawrence, Posyniak, Michał, Prange, Marc, Quiñones Meléndez, Estefanía, Radtke, Jule, Ramage, Karim, Reimann, Jens, Renault, Lionel, Reus, Klaus, Reyes, Ashford, Ribbe, Joachim, Ringel, Maximilian, Ritschel, Markus, Rocha, Cesar B., Rochetin, Nicolas, Röttenbacher, Johannes, Rollo, Callum, Royer, Haley, Sadoulet, Pauline, Saffin, Leo, Sandiford, Sanola, Sandu, Irina, Schäfer, Michael, Schemann, Vera, Schirmacher, Imke, Schlenczek, Oliver, Schmidt, Jerome, Schröder, Marcel, Schwarzenboeck, Alfons, Sealy, Andrea, Senff, Christoph J., Serikov, Ilya, Shohan, Samkeyat, Siddle, Elizabeth, Smirnov, Alexander, Späth, Florian, Spooner, Branden, Stolla, M. Katharina, Szkółka, Wojciech, de Szoeke, Simon P., Tarot, Stéphane, Tetoni, Eleni, Thompson, Elizabeth, Thomson, Jim, Tomassini, Lorenzo, Totems, Julien, Ubele, Alma Anna, Villiger, Leonie, von Arx, Jan, Wagner, Thomas, Walther, Andi, Webber, Ben, Wendisch, Manfred, Whitehall, Shanice, Wiltshire, Anton, Wing, Allison A., Wirth, Martin, Wiskandt, Jonathan, Wolf, Kevin, Worbes, Ludwig, Wright, Ethan, Wulfmeyer, Volker, Young, Shanea, Zhang, Chidong, Zhang, Dongxiao, Ziemen, Florian, Zinner, Tobias, Zöger, Martin, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Stevens, Bjorn, Bony, Sandrine, Farrell, David, Ament, Felix, Blyth, Alan, Fairall, Christopher, Karstensen, Johannes, Quinn, Patricia K., Speich, Sabrina, Acquistapace, Claudia, Aemisegger, Franziska, Albright, Anna Lea, Bellenger, Hugo, Bodenschatz, Eberhard, Caesar, Kathy-Ann, Chewitt-Lucas, Rebecca, de Boer, Gijs, Delanoë, Julien, Denby, Leif, Ewald, Florian, Fildier, Benjamin, Forde, Marvin, George, Geet, Gross, Silke, Hagen, Martin, Hausold, Andrea, Heywood, Karen J., Hirsch, Lutz, Jacob, Marek, Jansen, Friedhelm, Kinne, Stefan, Klocke, Daniel, Kölling, Tobias, Konow, Heike, Lothon, Marie, Mohr, Wiebke, Naumann, Ann Kristin, Nuijens, Louise, Olivier, Léa, Pincus, Robert, Pöhlker, Mira, Reverdin, Gilles, Roberts, Gregory, Schnitt, Sabrina, Schulz, Hauke, Siebesma, A. Pier, Stephan, Claudia Christine, Sullivan, Peter, Touzé-Peiffer, Ludovic, Vial, Jessica, Vogel, Raphaela, Zuidema, Paquita, Alexander, Nicola, Alves, Lyndon, Arixi, Sophian, Asmath, Hamish, Bagheri, Gholamhossein, Baier, Katharina, Bailey, Adriana, Baranowski, Dariusz, Baron, Alexandre, Barrau, Sébastien, Barrett, Paul A., Batier, Frédéric, Behrendt, Andreas, Bendinger, Arne, Beucher, Florent, Bigorre, Sebastien, Blades, Edmund, Blossey, Peter, Bock, Olivier, Böing, Steven, Bosser, Pierre, Bourras, Denis, Bouruet-Aubertot, Pascale, Bower, Keith, Branellec, Pierre, Branger, Hubert, Brennek, Michal, Brewer, Alan, Brilouet, Pierre-Etienne, Brügmann, Björn, Buehler, Stefan A., Burke, Elmo, Burton, Ralph, Calmer, Radiance, Canonici, Jean-Christophe, Carton, Xavier, Cato Jr., Gregory, Charles, Jude Andre, Chazette, Patrick, Chen, Yanxu, Chilinski, Michal T., Choularton, Thomas, Chuang, Patrick, Clarke, Shamal, Coe, Hugh, Cornet, Céline, Coutris, Pierre, Couvreux, Fleur, Crewell, Susanne, Cronin, Timothy, Cui, Zhiqiang, Cuypers, Yannis, Daley, Alton, Damerell, Gillian M., Dauhut, Thibaut, Deneke, Hartwig, Desbios, Jean-Philippe, Dörner, Steffen, Donner, Sebastian, Douet, Vincent, Drushka, Kyla, Dütsch, Marina, Ehrlich, André, Emanuel, Kerry, Emmanouilidis, Alexandros, Etienne, Jean-Claude, Etienne-Leblanc, Sheryl, Faure, Ghislain, Feingold, Graham, Ferrero, Luca, Fix, Andreas, Flamant, Cyrille, Flatau, Piotr Jacek, Foltz, Gregory R., Forster, Linda, Furtuna, Iulian, Gadian, Alan, Galewsky, Joseph, Gallagher, Martin, Gallimore, Peter, Gaston, Cassandra, Gentemann, Chelle, Geyskens, Nicolas, Giez, Andreas, Gollop, John, Gouirand, Isabelle, Gourbeyre, Christophe, de Graaf, Dörte, de Groot, Geiske E., Grosz, Robert, Güttler, Johannes, Gutleben, Manuel, Hall, Kashawn, Harris, George, Helfer, Kevin C., Henze, Dean, Herbert, Calvert, Holanda, Bruna, Ibanez-Landeta, Antonio, Intrieri, Janet, Iyer, Suneil, Julien, Fabrice, Kalesse, Heike, Kazil, Jan, Kellman, Alexander, Kidane, Abiel T., Kirchner, Ulrike, Klingebiel, Marcus, Körner, Mareike, Kremper, Leslie Ann, Kretzschmar, Jan, Krüger, Ovid, Kumala, Wojciech, Kurz, Armin, L'Hégaret, Pierre, Labaste, Matthieu, Lachlan-Cope, Tom, Laing, Arlene, Landschützer, Peter, Lang, Theresa, Lange, Diego, Lange, Ingo, Laplace, Clément, Lavik, Gauke, Laxenaire, Rémi, Le Bihan, Caroline, Leandro, Mason, Lefevre, Nathalie, Lena, Marius, Lenschow, Donald, Li, Qiang, Lloyd, Gary, Los, Sebastian, Losi, Niccolò, Lovell, Oscar, Luneau, Christopher, Makuch, Przemyslaw, Malinowski, Szymon, Manta, Gaston, Marinou, Eleni, Marsden, Nicholas, Masson, Sebastien, Maury, Nicolas, Mayer, Bernhard, Mayers-Als, Margarette, Mazel, Christophe, McGeary, Wayne, McWilliams, James C., Mech, Mario, Mehlmann, Melina, Meroni, Agostino Niyonkuru, Mieslinger, Theresa, Minikin, Andreas, Minnett, Peter, Möller, Gregor, Morfa Avalos, Yanmichel, Muller, Caroline, Musat, Ionela, Napoli, Anna, Neuberger, Almuth, Noisel, Christophe, Noone, David, Nordsiek, Freja, Nowak, Jakub L., Oswald, Lothar, Parker, Douglas J., Peck, Carolyn, Person, Renaud, Philippi, Miriam, Plueddemann, Albert, Pöhlker, Christopher, Pörtge, Veronika, Pöschl, Ulrich, Pologne, Lawrence, Posyniak, Michał, Prange, Marc, Quiñones Meléndez, Estefanía, Radtke, Jule, Ramage, Karim, Reimann, Jens, Renault, Lionel, Reus, Klaus, Reyes, Ashford, Ribbe, Joachim, Ringel, Maximilian, Ritschel, Markus, Rocha, Cesar B., Rochetin, Nicolas, Röttenbacher, Johannes, Rollo, Callum, Royer, Haley, Sadoulet, Pauline, Saffin, Leo, Sandiford, Sanola, Sandu, Irina, Schäfer, Michael, Schemann, Vera, Schirmacher, Imke, Schlenczek, Oliver, Schmidt, Jerome, Schröder, Marcel, Schwarzenboeck, Alfons, Sealy, Andrea, Senff, Christoph J., Serikov, Ilya, Shohan, Samkeyat, Siddle, Elizabeth, Smirnov, Alexander, Späth, Florian, Spooner, Branden, Stolla, M. Katharina, Szkółka, Wojciech, de Szoeke, Simon P., Tarot, Stéphane, Tetoni, Eleni, Thompson, Elizabeth, Thomson, Jim, Tomassini, Lorenzo, Totems, Julien, Ubele, Alma Anna, Villiger, Leonie, von Arx, Jan, Wagner, Thomas, Walther, Andi, Webber, Ben, Wendisch, Manfred, Whitehall, Shanice, Wiltshire, Anton, Wing, Allison A., Wirth, Martin, Wiskandt, Jonathan, Wolf, Kevin, Worbes, Ludwig, Wright, Ethan, Wulfmeyer, Volker, Young, Shanea, Zhang, Chidong, Zhang, Dongxiao, Ziemen, Florian, Zinner, Tobias, and Zöger, Martin

Abstract

Abstract. The science guiding the EUREC4A campaign and its measurements is presented. EUREC4A comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic – eastward and southeastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, EUREC4A marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or the life cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso- (200 km) and larger (500 km) scales, roughly 400 h of flight time by four heavily instrumented research aircraft; four global-class research vessels; an advanced ground-based cloud observatory; scores of autonomous observing platforms operating in the upper ocean (nearly 10 000 profiles), lower atmosphere (continuous profiling), and along the air–sea interface; a network of water stable isotopologue measurements; targeted tasking of satellite remote sensing; and modeling with a new generation of weather and climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that EUREC4A explored – from North Brazil Current rings to turbulence-induced clustering of cloud droplets and its influence on warm-rain formation – are presented along with an overview of EUREC4A's outreach activities, environmental impact, and guidelines for scientific practice. Track data for all platforms are standardized and accessible at https://doi.org/10.25326/165 (Stevens, 2021), and a film documenting the campaign is provided as a video supplement.

Published
2023

10. Distinct secondary ice production processes observed in radar Doppler spectra: insights from a case study.

Author

Billault-Roux, Anne-Claire, Georgakaki, Paraskevi, Gehring, Josué, Jaffeux, Louis, Schwarzenboeck, Alfons, Coutris, Pierre, Nenes, Athanasios, and Berne, Alexis

Subjects
DOPPLER radar, MANUFACTURING processes, ICE nuclei, RADAR meteorology, REMOTE sensing, ICE, ICE clouds, SUBGLACIAL lakes, ICE crystals
Abstract

Secondary ice production (SIP) has an essential role in cloud and precipitation microphysics. In recent years, substantial insights were gained into SIP by combining experimental, modeling, and observational approaches. Remote sensing instruments, among them meteorological radars, offer the possibility of studying clouds and precipitation in extended areas over long time periods and are highly valuable to understand the spatiotemporal structure of microphysical processes. Multi-modal Doppler spectra measured by vertically pointing radars reveal the coexistence, within a radar resolution volume, of hydrometeor populations with distinct properties; as such, they can provide decisive insight into precipitation microphysics. This paper leverages polarimetric radar Doppler spectra as a tool to study the microphysical processes that took place during a snowfall event on 27 January 2021 in the Swiss Jura Mountains during the ICE GENESIS campaign. A multi-layered cloud system was present, with ice particles sedimenting through a supercooled liquid water (SLW) layer in a seeder–feeder configuration. Building on a Doppler peak detection algorithm, we implement a peak labeling procedure to identify the particle type(s) that may be present within a radar resolution volume. With this approach, we can visualize spatiotemporal features in the radar time series that point to the occurrence of distinct mechanisms during different stages of the event. By focusing on three 30 min phases of the case study and by using the detailed information contained in the Doppler spectra, together with dual-frequency radar measurements, aircraft in situ images, and simulated profiles of atmospheric variables, we narrow down the possible processes that could be responsible for the observed signatures. Depending on the availability of SLW and the droplet sizes, on the temperature range, and on the interaction between the liquid and ice particles, various SIP processes are identified as plausible, with distinct fingerprints in the radar Doppler spectra. A simple modeling approach suggests that the ice crystal number concentrations likely exceed typical concentrations of ice-nucleating particles by 1 to 4 orders of magnitude. While a robust proof of occurrence of a given SIP mechanism cannot be easily established, the multi-sensor data provide various independent elements each supporting the proposed interpretations. [ABSTRACT FROM AUTHOR]

Published
2023
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12. Water isotopic characterisation of the cloud-circulation coupling in the North Atlantic trades. Part 1: A process-oriented evaluation of COSMOiso simulations with EUREC4A observations.

Author

Villiger, Leonie, Dütsch, Marina, Bony, Sandrine, Lothon, Marie, Pfahl, Stephan, Wernli, Heini, Brilouet, Pierre-Etienne, Chazette, Patrick, Coutris, Pierre, Delanoë, Julien, Flamant, Cyrille, Schwarzenboeck, Alfons, Werner, Martin, and Aemisegger, Franziska

Subjects
CUMULUS clouds, STABLE isotopes, ATMOSPHERIC circulation, STRATOCUMULUS clouds, FIELD research, REMOTE sensing, SPATIAL resolution
Abstract

Stable water isotope observations have the potential to provide information on cloud processes in the trade-wind region, in particular when combined with high-resolution model simulations. In order to evaluate this potential, nested convection-resolving COSMOiso simulations with horizontal grid spacings of 10, 5, and 1 km were carried out in this study over the tropical Atlantic for the time period of the EUREC4A field experiment. To keep the conditions in the domain as close as possible to the real meteorology, we applied a spectral nudging of horizontal winds towards reanalysis data. The comparison to airborne in situ and remote sensing observations shows that the three simulations are able to distinguish between different mesoscale cloud organisation patterns as well as between periods with comparably high and low rain rates. Precipitation, cloud fraction and liquid water content are sensitive to the grid spacing. Cloud fraction and liquid water content show a better agreement with aircraft observations with higher spatial resolution. Contrastingly, temperature, humidity, and isotopes in vapour remain fairly unaffected by the model resolution. A low-level cold-dry bias, including too depleted vapour in the subcloud and cloud layer and too enriched vapour in the free troposphere, is found in all three simulations. Furthermore, the simulated secondary isotope variable d-excess in vapour is overestimated compared to observations. Special attention is given to the cloud base level, the formation altitude of shallow cumulus clouds, which are rooted in the thermals of the subcloud layer. The temporal variability of the simulated isotope variables at cloud base agrees reasonably well with observations, with correlations of the flight-to-flight data as high as 0.69 for δ 2H and 0.74 for d-excess. A close examination of different mesoscale cloud base features, including clouds and clear-sky dry-warm patches, and their isotopic characteristics shows that i) these features are represented faithfully in the model with similar frequency of occurrence, isotope signals and specific humidity anomalies as found in the observations (+2 ‰ to +5 ‰ [+2 g kg−1] for precipitating clouds vs. −3 ‰ to −4 ‰ [−2 g kg−1] in dry-warm patches for δ 2H [ q ]) and ii) the δ 2H of cloud base vapour at the hourly time scale is mainly controlled by mesoscale transport and not by local microphysical processes while the d-excess is mainly controlled by large-scale drivers. Overall, this evaluation of COSMOiso, including the isotopic characterisation of cloud base features, suggests that the simulations can be used for investigating the role of atmospheric circulations on different scales for controlling the formation of shallow cumulus clouds in the trade-wind region, as will be done in part 2 of this study. Additionally, we provide explicit recommendations for adaptations of the modelling setup to be tested in future research. [ABSTRACT FROM AUTHOR]

Published
2023
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13. EUREC<sup>4</sup>A observations from the SAFIRE ATR42 aircraft

Author

Bony, Sandrine, primary, Lothon, Marie, additional, Delanoë, Julien, additional, Coutris, Pierre, additional, Etienne, Jean-Claude, additional, Aemisegger, Franziska, additional, Albright, Anna Lea, additional, André, Thierry, additional, Bellec, Hubert, additional, Baron, Alexandre, additional, Bourdinot, Jean-François, additional, Brilouet, Pierre-Etienne, additional, Bourdon, Aurélien, additional, Canonici, Jean-Christophe, additional, Caudoux, Christophe, additional, Chazette, Patrick, additional, Cluzeau, Michel, additional, Cornet, Céline, additional, Desbios, Jean-Philippe, additional, Duchanoy, Dominique, additional, Flamant, Cyrille, additional, Fildier, Benjamin, additional, Gourbeyre, Christophe, additional, Guiraud, Laurent, additional, Jiang, Tetyana, additional, Lainard, Claude, additional, Le Gac, Christophe, additional, Lendroit, Christian, additional, Lernould, Julien, additional, Perrin, Thierry, additional, Pouvesle, Frédéric, additional, Richard, Pascal, additional, Rochetin, Nicolas, additional, Salaün, Kevin, additional, Schwarzenboeck, Alfons, additional, Seurat, Guillaume, additional, Stevens, Bjorn, additional, Totems, Julien, additional, Touzé-Peiffer, Ludovic, additional, Vergez, Gilles, additional, Vial, Jessica, additional, Villiger, Leonie, additional, and Vogel, Raphaela, additional

Published
2022
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14. EUREC<sup>4</sup>A

Author

Stevens, Bjorn, primary, Bony, Sandrine, additional, Farrell, David, additional, Ament, Felix, additional, Blyth, Alan, additional, Fairall, Christopher, additional, Karstensen, Johannes, additional, Quinn, Patricia K., additional, Speich, Sabrina, additional, Acquistapace, Claudia, additional, Aemisegger, Franziska, additional, Albright, Anna Lea, additional, Bellenger, Hugo, additional, Bodenschatz, Eberhard, additional, Caesar, Kathy-Ann, additional, Chewitt-Lucas, Rebecca, additional, de Boer, Gijs, additional, Delanoë, Julien, additional, Denby, Leif, additional, Ewald, Florian, additional, Fildier, Benjamin, additional, Forde, Marvin, additional, George, Geet, additional, Gross, Silke, additional, Hagen, Martin, additional, Hausold, Andrea, additional, Heywood, Karen J., additional, Hirsch, Lutz, additional, Jacob, Marek, additional, Jansen, Friedhelm, additional, Kinne, Stefan, additional, Klocke, Daniel, additional, Kölling, Tobias, additional, Konow, Heike, additional, Lothon, Marie, additional, Mohr, Wiebke, additional, Naumann, Ann Kristin, additional, Nuijens, Louise, additional, Olivier, Léa, additional, Pincus, Robert, additional, Pöhlker, Mira, additional, Reverdin, Gilles, additional, Roberts, Gregory, additional, Schnitt, Sabrina, additional, Schulz, Hauke, additional, Siebesma, A. Pier, additional, Stephan, Claudia Christine, additional, Sullivan, Peter, additional, Touzé-Peiffer, Ludovic, additional, Vial, Jessica, additional, Vogel, Raphaela, additional, Zuidema, Paquita, additional, Alexander, Nicola, additional, Alves, Lyndon, additional, Arixi, Sophian, additional, Asmath, Hamish, additional, Bagheri, Gholamhossein, additional, Baier, Katharina, additional, Bailey, Adriana, additional, Baranowski, Dariusz, additional, Baron, Alexandre, additional, Barrau, Sébastien, additional, Barrett, Paul A., additional, Batier, Frédéric, additional, Behrendt, Andreas, additional, Bendinger, Arne, additional, Beucher, Florent, additional, Bigorre, Sebastien, additional, Blades, Edmund, additional, Blossey, Peter, additional, Bock, Olivier, additional, Böing, Steven, additional, Bosser, Pierre, additional, Bourras, Denis, additional, Bouruet-Aubertot, Pascale, additional, Bower, Keith, additional, Branellec, Pierre, additional, Branger, Hubert, additional, Brennek, Michal, additional, Brewer, Alan, additional, Brilouet, Pierre-Etienne, additional, Brügmann, Björn, additional, Buehler, Stefan A., additional, Burke, Elmo, additional, Burton, Ralph, additional, Calmer, Radiance, additional, Canonici, Jean-Christophe, additional, Carton, Xavier, additional, Cato Jr., Gregory, additional, Charles, Jude Andre, additional, Chazette, Patrick, additional, Chen, Yanxu, additional, Chilinski, Michal T., additional, Choularton, Thomas, additional, Chuang, Patrick, additional, Clarke, Shamal, additional, Coe, Hugh, additional, Cornet, Céline, additional, Coutris, Pierre, additional, Couvreux, Fleur, additional, Crewell, Susanne, additional, Cronin, Timothy, additional, Cui, Zhiqiang, additional, Cuypers, Yannis, additional, Daley, Alton, additional, Damerell, Gillian M., additional, Dauhut, Thibaut, additional, Deneke, Hartwig, additional, Desbios, Jean-Philippe, additional, Dörner, Steffen, additional, Donner, Sebastian, additional, Douet, Vincent, additional, Drushka, Kyla, additional, Dütsch, Marina, additional, Ehrlich, André, additional, Emanuel, Kerry, additional, Emmanouilidis, Alexandros, additional, Etienne, Jean-Claude, additional, Etienne-Leblanc, Sheryl, additional, Faure, Ghislain, additional, Feingold, Graham, additional, Ferrero, Luca, additional, Fix, Andreas, additional, Flamant, Cyrille, additional, Flatau, Piotr Jacek, additional, Foltz, Gregory R., additional, Forster, Linda, additional, Furtuna, Iulian, additional, Gadian, Alan, additional, Galewsky, Joseph, additional, Gallagher, Martin, additional, Gallimore, Peter, additional, Gaston, Cassandra, additional, Gentemann, Chelle, additional, Geyskens, Nicolas, additional, Giez, Andreas, additional, Gollop, John, additional, Gouirand, Isabelle, additional, Gourbeyre, Christophe, additional, de Graaf, Dörte, additional, de Groot, Geiske E., additional, Grosz, Robert, additional, Güttler, Johannes, additional, Gutleben, Manuel, additional, Hall, Kashawn, additional, Harris, George, additional, Helfer, Kevin C., additional, Henze, Dean, additional, Herbert, Calvert, additional, Holanda, Bruna, additional, Ibanez-Landeta, Antonio, additional, Intrieri, Janet, additional, Iyer, Suneil, additional, Julien, Fabrice, additional, Kalesse, Heike, additional, Kazil, Jan, additional, Kellman, Alexander, additional, Kidane, Abiel T., additional, Kirchner, Ulrike, additional, Klingebiel, Marcus, additional, Körner, Mareike, additional, Kremper, Leslie Ann, additional, Kretzschmar, Jan, additional, Krüger, Ovid, additional, Kumala, Wojciech, additional, Kurz, Armin, additional, L'Hégaret, Pierre, additional, Labaste, Matthieu, additional, Lachlan-Cope, Tom, additional, Laing, Arlene, additional, Landschützer, Peter, additional, Lang, Theresa, additional, Lange, Diego, additional, Lange, Ingo, additional, Laplace, Clément, additional, Lavik, Gauke, additional, Laxenaire, Rémi, additional, Le Bihan, Caroline, additional, Leandro, Mason, additional, Lefevre, Nathalie, additional, Lena, Marius, additional, Lenschow, Donald, additional, Li, Qiang, additional, Lloyd, Gary, additional, Los, Sebastian, additional, Losi, Niccolò, additional, Lovell, Oscar, additional, Luneau, Christopher, additional, Makuch, Przemyslaw, additional, Malinowski, Szymon, additional, Manta, Gaston, additional, Marinou, Eleni, additional, Marsden, Nicholas, additional, Masson, Sebastien, additional, Maury, Nicolas, additional, Mayer, Bernhard, additional, Mayers-Als, Margarette, additional, Mazel, Christophe, additional, McGeary, Wayne, additional, McWilliams, James C., additional, Mech, Mario, additional, Mehlmann, Melina, additional, Meroni, Agostino Niyonkuru, additional, Mieslinger, Theresa, additional, Minikin, Andreas, additional, Minnett, Peter, additional, Möller, Gregor, additional, Morfa Avalos, Yanmichel, additional, Muller, Caroline, additional, Musat, Ionela, additional, Napoli, Anna, additional, Neuberger, Almuth, additional, Noisel, Christophe, additional, Noone, David, additional, Nordsiek, Freja, additional, Nowak, Jakub L., additional, Oswald, Lothar, additional, Parker, Douglas J., additional, Peck, Carolyn, additional, Person, Renaud, additional, Philippi, Miriam, additional, Plueddemann, Albert, additional, Pöhlker, Christopher, additional, Pörtge, Veronika, additional, Pöschl, Ulrich, additional, Pologne, Lawrence, additional, Posyniak, Michał, additional, Prange, Marc, additional, Quiñones Meléndez, Estefanía, additional, Radtke, Jule, additional, Ramage, Karim, additional, Reimann, Jens, additional, Renault, Lionel, additional, Reus, Klaus, additional, Reyes, Ashford, additional, Ribbe, Joachim, additional, Ringel, Maximilian, additional, Ritschel, Markus, additional, Rocha, Cesar B., additional, Rochetin, Nicolas, additional, Röttenbacher, Johannes, additional, Rollo, Callum, additional, Royer, Haley, additional, Sadoulet, Pauline, additional, Saffin, Leo, additional, Sandiford, Sanola, additional, Sandu, Irina, additional, Schäfer, Michael, additional, Schemann, Vera, additional, Schirmacher, Imke, additional, Schlenczek, Oliver, additional, Schmidt, Jerome, additional, Schröder, Marcel, additional, Schwarzenboeck, Alfons, additional, Sealy, Andrea, additional, Senff, Christoph J., additional, Serikov, Ilya, additional, Shohan, Samkeyat, additional, Siddle, Elizabeth, additional, Smirnov, Alexander, additional, Späth, Florian, additional, Spooner, Branden, additional, Stolla, M. Katharina, additional, Szkółka, Wojciech, additional, de Szoeke, Simon P., additional, Tarot, Stéphane, additional, Tetoni, Eleni, additional, Thompson, Elizabeth, additional, Thomson, Jim, additional, Tomassini, Lorenzo, additional, Totems, Julien, additional, Ubele, Alma Anna, additional, Villiger, Leonie, additional, von Arx, Jan, additional, Wagner, Thomas, additional, Walther, Andi, additional, Webber, Ben, additional, Wendisch, Manfred, additional, Whitehall, Shanice, additional, Wiltshire, Anton, additional, Wing, Allison A., additional, Wirth, Martin, additional, Wiskandt, Jonathan, additional, Wolf, Kevin, additional, Worbes, Ludwig, additional, Wright, Ethan, additional, Wulfmeyer, Volker, additional, Young, Shanea, additional, Zhang, Chidong, additional, Zhang, Dongxiao, additional, Ziemen, Florian, additional, Zinner, Tobias, additional, and Zöger, Martin, additional

Published
2021
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15. EUREC4A

Author

Stevens, Bjorn, Bony, Sandrine, Farrell, David, Ament, Felix, Blyth, Alan, Fairall, Christopher, Karstensen, Johannes, Quinn, Patricia K., Speich, Sabrina, Acquistapace, Claudia, Aemisegger, Franziska, Albright, Anna Lea, Bellenger, Hugo, Bodenschatz, Eberhard, Caesar, Kathy-ann, Chewitt-lucas, Rebecca, De Boer, Gijs, Delanoe, Julien, Denby, Leif, Ewald, Florian, Fildier, Benjamin, Forde, Marvin, George, Geet, Gross, Silke, Hagen, Martin, Hausold, Andrea, Heywood, Karen J., Hirsch, Lutz, Jacob, Marek, Jansen, Friedhelm, Kinne, Stefan, Klocke, Daniel, Kolling, Tobias, Konow, Heike, Lothon, Marie, Mohr, Wiebke, Naumann, Ann Kristin, Nuijens, Louise, Olivier, Lea, Pincus, Robert, Pohlker, Mira, Reverdin, Gilles, Roberts, Gregory, Schnitt, Sabrina, Schulz, Hauke, Siebesma, A. Pier, Stephan, Claudia Christine, Sullivan, Peter, Touze-peiffer, Ludovic, Vial, Jessica, Vogel, Raphaela, Zuidema, Paquita, Alexander, Nicola, Alves, Lyndon, Arixi, Sophian, Asmath, Hamish, Bagheri, Gholamhossein, Baier, Katharina, Bailey, Adriana, Baranowski, Dariusz, Baron, Alexandre, Barrau, Sebastien, Barrett, Paul A., Batier, Frederic, Behrendt, Andreas, Bendinger, Arne, Beucher, Florent, Bigorre, Sebastien, Blades, Edmund, Blossey, Peter, Bock, Olivier, Boing, Steven, Bosser, Pierre, Bourras, Denis, Bouruet-aubertot, Pascale, Bower, Keith, Branellec, Pierre, Branger, Hubert, Brennek, Michal, Brewer, Alan, Brilouet, Pierre Etienne, Brugmann, Bjorn, Buehler, Stefan A., Burke, Elmo, Burton, Ralph, Calmer, Radiance, Canonici, Jean-christophe, Carton, Xavier, Cato, Gregory, Jr., Charles, Jude Andre, Chazette, Patrick, Chen, Yanxu, Chilinski, Michal T., Choularton, Thomas, Chuang, Patrick, Clarke, Shamal, Coe, Hugh, Cornet, Celine, Coutris, Pierre, Couvreux, Fleur, Crewell, Susanne, Cronin, Timothy, Cui, Zhiqiang, Cuypers, Yannis, Daley, Alton, Damerell, Gillian M., Dauhut, Thibaut, Deneke, Hartwig, Desbios, Jean-philippe, Dorner, Steffen, Donner, Sebastian, Douet, Vincent, Drushka, Kyla, Dutsch, Marina, Ehrlich, Andre, Emanuel, Kerry, Emmanouilidis, Alexandros, Etienne, Jean-claude, Etienne-leblanc, Sheryl, Faure, Ghislain, Feingold, Graham, Ferrero, Luca, Fix, Andreas, Flamant, Cyrille, Flatau, Piotr Jacek, Foltz, Gregory R., Forster, Linda, Furtuna, Iulian, Gadian, Alan, Galewsky, Joseph, Gallagher, Martin, Gallimore, Peter, Gaston, Cassandra, Gentemann, Chelle, Geyskens, Nicolas, Giez, Andreas, Gollop, John, Gouirand, Isabelle, Gourbeyre, Christophe, De Graaf, Dorte, De Groot, Geiske E., Grosz, Robert, Guttler, Johannes, Gutleben, Manuel, Hall, Kashawn, Harris, George, Helfer, Kevin C., Henze, Dean, Herbert, Calvert, Holanda, Bruna, Ibanez-landeta, Antonio, Intrieri, Janet, Iyer, Suneil, Julien, Fabrice, Kalesse, Heike, Kazil, Jan, Kellman, Alexander, Kidane, Abiel T., Kirchner, Ulrike, Klingebiel, Marcus, Korner, Mareike, Kremper, Leslie Ann, Kretzschmar, Jan, Kruger, Ovid, Kumala, Wojciech, Kurz, Armin, L'Hegaret, Pierre, Labaste, Matthieu, Lachlan-cope, Tom, Laing, Arlene, Landschutzer, Peter, Lang, Theresa, Lange, Diego, Lange, Ingo, Laplace, Clement, Lavik, Gauke, Laxenaire, Remi, Le Bihan, Caroline, Leandro, Mason, Lefevre, Nathalie, Lena, Marius, Lenschow, Donald, Li, Qiang, Lloyd, Gary, Los, Sebastian, Losi, Niccolo, Lovell, Oscar, Luneau, Christopher, Makuch, Przemyslaw, Malinowski, Szymon, Manta, Gaston, Marinou, Eleni, Marsden, Nicholas, Masson, Sebastien, Maury, Nicolas, Mayer, Bernhard, Mayers-als, Margarette, Mazel, Christophe, Mcgeary, Wayne, Mcwilliams, James C., Mech, Mario, Mehlmann, Melina, Meroni, Agostino Niyonkuru, Mieslinger, Theresa, Minikin, Andreas, Minnett, Peter, Moller, Gregor, Avalos, Yanmichel Morfa, Muller, Caroline, Musat, Ionela, Napoli, Anna, Neuberger, Almuth, Noisel, Christophe, Noone, David, Nordsiek, Freja, Nowak, Jakub L., Oswald, Lothar, Parker, Douglas J., Peck, Carolyn, Person, Renaud, Philippi, Miriam, Plueddemann, Albert, Pohlker, Christopher, Portge, Veronika, Poschl, Ulrich, Pologne, Lawrence, Posyniak, Michal, Prange, Marc, Melendez, Estefania Quinones, Radtke, Jule, Ramage, Karim, Reimann, Jens, Renault, Lionel, Reus, Klaus, Reyes, Ashford, Ribbe, Joachim, Ringel, Maximilian, Ritschel, Markus, Rocha, Cesar B., Rochetin, Nicolas, Rottenbacher, Johannes, Rollo, Callum, Royer, Haley, Sadoulet, Pauline, Saffin, Leo, Sandiford, Sanola, Sandu, Irina, Schafer, Michael, Schemann, Vera, Schirmacher, Imke, Schlenczek, Oliver, Schmidt, Jerome, Schroder, Marcel, Schwarzenboeck, Alfons, Sealy, Andrea, Senff, Christoph J., Serikov, Ilya, Shohan, Samkeyat, Siddle, Elizabeth, Smirnov, Alexander, Spath, Florian, Spooner, Branden, Stolla, M. Katharina, Szkolka, Wojciech, De Szoeke, Simon P., Tarot, Stephane, Tetoni, Eleni, Thompson, Elizabeth, Thomson, Jim, Tomassini, Lorenzo, Totems, Julien, Ubele, Alma Anna, Villiger, Leonie, Von Arx, Jan, Wagner, Thomas, Walther, Andi, Webber, Ben, Wendisch, Manfred, Whitehall, Shanice, Wiltshire, Anton, Wing, Allison A., Wirth, Martin, Wiskandt, Jonathan, Wolf, Kevin, Worbes, Ludwig, Wright, Ethan, Wulfmeyer, Volker, Young, Shanea, Zhang, Chidong, Zhang, Dongxiao, Ziemen, Florian, Zinner, Tobias, Zoger, Martin, Stevens, Bjorn, Bony, Sandrine, Farrell, David, Ament, Felix, Blyth, Alan, Fairall, Christopher, Karstensen, Johannes, Quinn, Patricia K., Speich, Sabrina, Acquistapace, Claudia, Aemisegger, Franziska, Albright, Anna Lea, Bellenger, Hugo, Bodenschatz, Eberhard, Caesar, Kathy-ann, Chewitt-lucas, Rebecca, De Boer, Gijs, Delanoe, Julien, Denby, Leif, Ewald, Florian, Fildier, Benjamin, Forde, Marvin, George, Geet, Gross, Silke, Hagen, Martin, Hausold, Andrea, Heywood, Karen J., Hirsch, Lutz, Jacob, Marek, Jansen, Friedhelm, Kinne, Stefan, Klocke, Daniel, Kolling, Tobias, Konow, Heike, Lothon, Marie, Mohr, Wiebke, Naumann, Ann Kristin, Nuijens, Louise, Olivier, Lea, Pincus, Robert, Pohlker, Mira, Reverdin, Gilles, Roberts, Gregory, Schnitt, Sabrina, Schulz, Hauke, Siebesma, A. Pier, Stephan, Claudia Christine, Sullivan, Peter, Touze-peiffer, Ludovic, Vial, Jessica, Vogel, Raphaela, Zuidema, Paquita, Alexander, Nicola, Alves, Lyndon, Arixi, Sophian, Asmath, Hamish, Bagheri, Gholamhossein, Baier, Katharina, Bailey, Adriana, Baranowski, Dariusz, Baron, Alexandre, Barrau, Sebastien, Barrett, Paul A., Batier, Frederic, Behrendt, Andreas, Bendinger, Arne, Beucher, Florent, Bigorre, Sebastien, Blades, Edmund, Blossey, Peter, Bock, Olivier, Boing, Steven, Bosser, Pierre, Bourras, Denis, Bouruet-aubertot, Pascale, Bower, Keith, Branellec, Pierre, Branger, Hubert, Brennek, Michal, Brewer, Alan, Brilouet, Pierre Etienne, Brugmann, Bjorn, Buehler, Stefan A., Burke, Elmo, Burton, Ralph, Calmer, Radiance, Canonici, Jean-christophe, Carton, Xavier, Cato, Gregory, Jr., Charles, Jude Andre, Chazette, Patrick, Chen, Yanxu, Chilinski, Michal T., Choularton, Thomas, Chuang, Patrick, Clarke, Shamal, Coe, Hugh, Cornet, Celine, Coutris, Pierre, Couvreux, Fleur, Crewell, Susanne, Cronin, Timothy, Cui, Zhiqiang, Cuypers, Yannis, Daley, Alton, Damerell, Gillian M., Dauhut, Thibaut, Deneke, Hartwig, Desbios, Jean-philippe, Dorner, Steffen, Donner, Sebastian, Douet, Vincent, Drushka, Kyla, Dutsch, Marina, Ehrlich, Andre, Emanuel, Kerry, Emmanouilidis, Alexandros, Etienne, Jean-claude, Etienne-leblanc, Sheryl, Faure, Ghislain, Feingold, Graham, Ferrero, Luca, Fix, Andreas, Flamant, Cyrille, Flatau, Piotr Jacek, Foltz, Gregory R., Forster, Linda, Furtuna, Iulian, Gadian, Alan, Galewsky, Joseph, Gallagher, Martin, Gallimore, Peter, Gaston, Cassandra, Gentemann, Chelle, Geyskens, Nicolas, Giez, Andreas, Gollop, John, Gouirand, Isabelle, Gourbeyre, Christophe, De Graaf, Dorte, De Groot, Geiske E., Grosz, Robert, Guttler, Johannes, Gutleben, Manuel, Hall, Kashawn, Harris, George, Helfer, Kevin C., Henze, Dean, Herbert, Calvert, Holanda, Bruna, Ibanez-landeta, Antonio, Intrieri, Janet, Iyer, Suneil, Julien, Fabrice, Kalesse, Heike, Kazil, Jan, Kellman, Alexander, Kidane, Abiel T., Kirchner, Ulrike, Klingebiel, Marcus, Korner, Mareike, Kremper, Leslie Ann, Kretzschmar, Jan, Kruger, Ovid, Kumala, Wojciech, Kurz, Armin, L'Hegaret, Pierre, Labaste, Matthieu, Lachlan-cope, Tom, Laing, Arlene, Landschutzer, Peter, Lang, Theresa, Lange, Diego, Lange, Ingo, Laplace, Clement, Lavik, Gauke, Laxenaire, Remi, Le Bihan, Caroline, Leandro, Mason, Lefevre, Nathalie, Lena, Marius, Lenschow, Donald, Li, Qiang, Lloyd, Gary, Los, Sebastian, Losi, Niccolo, Lovell, Oscar, Luneau, Christopher, Makuch, Przemyslaw, Malinowski, Szymon, Manta, Gaston, Marinou, Eleni, Marsden, Nicholas, Masson, Sebastien, Maury, Nicolas, Mayer, Bernhard, Mayers-als, Margarette, Mazel, Christophe, Mcgeary, Wayne, Mcwilliams, James C., Mech, Mario, Mehlmann, Melina, Meroni, Agostino Niyonkuru, Mieslinger, Theresa, Minikin, Andreas, Minnett, Peter, Moller, Gregor, Avalos, Yanmichel Morfa, Muller, Caroline, Musat, Ionela, Napoli, Anna, Neuberger, Almuth, Noisel, Christophe, Noone, David, Nordsiek, Freja, Nowak, Jakub L., Oswald, Lothar, Parker, Douglas J., Peck, Carolyn, Person, Renaud, Philippi, Miriam, Plueddemann, Albert, Pohlker, Christopher, Portge, Veronika, Poschl, Ulrich, Pologne, Lawrence, Posyniak, Michal, Prange, Marc, Melendez, Estefania Quinones, Radtke, Jule, Ramage, Karim, Reimann, Jens, Renault, Lionel, Reus, Klaus, Reyes, Ashford, Ribbe, Joachim, Ringel, Maximilian, Ritschel, Markus, Rocha, Cesar B., Rochetin, Nicolas, Rottenbacher, Johannes, Rollo, Callum, Royer, Haley, Sadoulet, Pauline, Saffin, Leo, Sandiford, Sanola, Sandu, Irina, Schafer, Michael, Schemann, Vera, Schirmacher, Imke, Schlenczek, Oliver, Schmidt, Jerome, Schroder, Marcel, Schwarzenboeck, Alfons, Sealy, Andrea, Senff, Christoph J., Serikov, Ilya, Shohan, Samkeyat, Siddle, Elizabeth, Smirnov, Alexander, Spath, Florian, Spooner, Branden, Stolla, M. Katharina, Szkolka, Wojciech, De Szoeke, Simon P., Tarot, Stephane, Tetoni, Eleni, Thompson, Elizabeth, Thomson, Jim, Tomassini, Lorenzo, Totems, Julien, Ubele, Alma Anna, Villiger, Leonie, Von Arx, Jan, Wagner, Thomas, Walther, Andi, Webber, Ben, Wendisch, Manfred, Whitehall, Shanice, Wiltshire, Anton, Wing, Allison A., Wirth, Martin, Wiskandt, Jonathan, Wolf, Kevin, Worbes, Ludwig, Wright, Ethan, Wulfmeyer, Volker, Young, Shanea, Zhang, Chidong, Zhang, Dongxiao, Ziemen, Florian, Zinner, Tobias, and Zoger, Martin

Abstract

The science guiding the \EURECA campaign and its measurements are presented. \EURECA comprised roughly five weeks of measurements in the downstream winter trades of the North Atlantic — eastward and south-eastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, \EURECA marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or, or the life-cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso (200 km) and larger (500 km) scales, roughly four hundred hours of flight time by four heavily instrumented research aircraft, four global-ocean class research vessels, an advanced ground-based cloud observatory, a flotilla of autonomous or tethered measurement devices operating in the upper ocean (nearly 10000 profiles), lower atmosphere (continuous profiling), and along the air-sea interface, a network of water stable isotopologue measurements, complemented by special programmes of satellite remote sensing and modeling with a new generation of weather/climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that \EURECA explored — from Brazil Ring Current Eddies to turbulence induced clustering of cloud droplets and its influence on warm-rain formation — are presented along with an overview \EURECA’s outreach activities, environmental impact, and guidelines for scientific practice.

Published
2021
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17. EUREC4A

Author

Stevens, Bjorn, primary, Bony, Sandrine, additional, Farrell, David, additional, Ament, Felix, additional, Blyth, Alan M., additional, Fairall, Christopher W., additional, Karstensen, Johannes, additional, Quinn, Patricia K., additional, Speich, Sabrina, additional, Acquistapace, Claudia, additional, Aemisegger, Franziska, additional, Albright, Anna Lea, additional, Bellenger, Hugo, additional, Bodenschatz, Eberhard, additional, Caesar, Kathy-Ann, additional, Chewitt-Lucas, Rebecca, additional, de Boer, Gijs, additional, Delanoë, Julien, additional, Denby, Leif Christopher, additional, Ewald, Florian, additional, Fildier, Benjamin, additional, Forde, Marvin, additional, George, Geet, additional, Gross, Silke, additional, Hagen, Martin, additional, Hausold, Andrea, additional, Heywood, Karen J., additional, Hirsch, Lutz, additional, Jacob, Marek, additional, Jansen, Friedhelm, additional, Kinne, Stefan, additional, Klocke, Daniel, additional, Kölling, Tobias, additional, Konow, Heike, additional, Lothon, Marie, additional, Mohr, Wiebke, additional, Naumann, Ann Kristin, additional, Nuijens, Louise, additional, Olivier, Léa, additional, Pincus, Robert, additional, Pöhlker, Mira L., additional, Reverdin, Gilles, additional, Roberts, Gregory, additional, Schnitt, Sabrina, additional, Schulz, Hauke, additional, Siebesma, Pier, additional, Stephan, Claudia Christine, additional, Sullivan, Peter P, additional, Touzé-Peiffer, Ludovic, additional, Vial, Jessica, additional, Vogel, Raphaela, additional, Zuidema, Paquita, additional, Alexander, Nicola, additional, Alves, Lyndon, additional, Arixi, Sophian, additional, Asmath, Hamish, additional, Bagheri, Gholamhossein, additional, Baier, Katharina, additional, Bailey, Adriana, additional, Baranowski, Dariusz B., additional, Baron, Alexandre, additional, Barrau, Sébastien, additional, Barrett, Paul Alan, additional, Batier, Frédéric, additional, Behrendt, Andreas, additional, Bendinger, Arne, additional, Beucher, Florent, additional, Bigorre, Sebastien, additional, Blades, Edmund, additional, Bock, Olivier, additional, Boeing, Steven J, additional, Bosser, Pierre, additional, Bourras, Denis, additional, Bouruet-Aubertot, Pascale, additional, Bower, Keith, additional, Branellec, Pierre, additional, Branger, Hubert, additional, Brennek, Michal, additional, Brewer, Alan, additional, Brilouet, Pierre-Etienne, additional, Brügmann, Björn, additional, Buehler, Stefan Alexander, additional, Burke, Elmo, additional, Burton, Ralph, additional, Calmer, Radiance, additional, Canonici, Jean-Christophe, additional, Carton, Xavier J., additional, Cato, Gregory, additional, Charles, Jude Andre, additional, Chazette, Patrick, additional, Chen, Yanxu, additional, Chiliński, Michał T, additional, Choularton, Tom, additional, Chuang, Patrick Y., additional, Clarke, Shamal, additional, Coe, Hugh, additional, Cornet, Céline, additional, Coutris, Pierre, additional, Couvreux, Fleur, additional, Crewell, Susanne, additional, Cronin, Timothy Wallace, additional, Cui, Zhiqiang, additional, Cuypers, Yannis, additional, Daley, Alton, additional, Damerell, Gillian Mary, additional, Dauhut, Thibaut, additional, Deneke, Hartwig M, additional, Desbios, Jean-Philippe, additional, Dörner, Steffen, additional, Donner, Sebastian, additional, Douet, Vincent, additional, Drushka, Kyla, additional, Dütsch, Marina, additional, Ehrlich, André, additional, Emanual, Kerry, additional, Emmanouilidis, Alexandros, additional, Etienne, Jean-Claude, additional, Etienne-Leblanc, Sheryl, additional, Faure, Ghislain, additional, Feingold, Graham, additional, Ferrero, Luca, additional, Fix, Andreas, additional, Flamant, Cyrille, additional, Flatau, Piotr J., additional, Foltz, Gregory R., additional, Forster, Linda, additional, Furtuna, Iulian, additional, Gadian, Alan, additional, Galewsky, Joseph, additional, Gallagher, Martin, additional, Gallimore, Peter, additional, Gaston, Cassandra J., additional, Gentemann, Chelle, additional, Geyskens, Nicolas, additional, Giez, Andreas, additional, Gollop, John, additional, Gouirand, Isabelle, additional, Gourbeyre, Christophe, additional, de Graaf, Dörte, additional, de Groot, Geiske E., additional, Grosz, Robert, additional, Güttler, Johannes, additional, Gutleben, Manuel, additional, Hall, Kashawn, additional, Harris, George, additional, Helfer, Kevin Christopher, additional, Henze, Dean, additional, Herbert, Calvert, additional, Holanda, Bruna, additional, Ibanez-Landeta, Antonio, additional, Intrieri, Janet M., additional, Iyer, Suneil, additional, Julien, Fabrice, additional, Kalesse, Heike, additional, Kazil, Jan, additional, Kellman, Alexander, additional, Kidane, Abiel T., additional, Kirchner, Ulrike, additional, Klingebiel, Marcus, additional, Körner, Mareike, additional, Kremper, Leslie Ann, additional, Kretzschmar, Jan, additional, Krüger, Ovid, additional, Kumala, Wojciech, additional, Kurz, Armin, additional, L'Hégaret, Pierre, additional, Labaste, Matthieu, additional, Lachlan-Cope, Tom A., additional, Laing, Arlene, additional, Landschützer, Peter, additional, Lang, Theresa, additional, Lange Vega, Diego, additional, Lange, Ingo, additional, Laplace, Clément, additional, Lavik, Gaute, additional, LAXENAIRE, Rémi, additional, Le Bihan, Caroline, additional, Leandro, Mason, additional, Lefèvre, Nathalie, additional, Lena, Marius, additional, Leschow, Donald, additional, Li, Qiang, additional, Lloyd, Gary, additional, Los, Sebastian, additional, Losi, Niccolò, additional, Lovell, Oscar, additional, Luneau, Christopher, additional, Makuch, Przemysław, additional, Malinowski, Szymon P, additional, Manta, Gaston, additional, Marinou, Eleni, additional, Marsden, Nicholas, additional, Masson, Sebastien, additional, Maury, Nicolas, additional, Mayer, Bernhard, additional, Mayers-Als, Margarette, additional, Mazel, Christophe, additional, McGeary, Wayne, additional, McWilliams, James C., additional, Mech, Mario, additional, Mehlmann, Melina, additional, Meroni, Agostino Niyonkuru, additional, Mieslinger, Theresa, additional, Minikin, Andreas, additional, Minnett, Peter, additional, Möller, Gregor, additional, Morfa Avalos, Yanmichel, additional, Muller, Caroline, additional, Musat, Ionela, additional, Napoli, Anna, additional, Neuberger, Almuth, additional, Noisel, Christophe, additional, Noone, David C, additional, Nordsiek, Freja, additional, Nowak, Jakub L, additional, Oswald, Lothar, additional, Parker, Douglas J., additional, Peck, Carolyn, additional, Person, Renaud, additional, Philippi, Miriam, additional, Plueddemann, Albert J., additional, Pöhlker, Christopher, additional, Pörtge, Veronika, additional, Pöschl, Ulrich, additional, Pologne, Lawrence, additional, Posyniak, Michal, additional, Prange, Marc, additional, Quiñones Meléndez, Estefanía, additional, Radtke, Jule, additional, Ramage, Karim, additional, Reimann, Jens, additional, Renault, Lionel, additional, Reus, Klaus, additional, Reyes, Ashford, additional, Ribbe, Joachim, additional, Ringel, Maximilian, additional, Ritschel, Markus, additional, Rocha, Cesar Barbedo, additional, Rochetin, Nicolas, additional, Röttenbacher, Johannes, additional, Rollo, Callum, additional, Royer, Haley, additional, Sadoulet, Pauline, additional, Saffin, Leo, additional, Sandiford, Sanola, additional, Sandu, Irina, additional, Schäfer, Michael, additional, Schemann, Vera, additional, Schirmacher, Imke, additional, Schlenczek, Oliver, additional, Schmidt, Jerome, additional, Schröder, Marcel, additional, Schwarzenboeck, Alfons, additional, Sealy, Andrea, additional, Senff, Christoph J, additional, Serikov, Ilya, additional, Shohan, Samkeyat, additional, Siddle, Elizabeth, additional, Smirnov, Alexander, additional, Späth, Florian, additional, Spooner, Branden, additional, Stolla, M. Katharina, additional, Szkółka, Wojciech, additional, de Szoeke, Simon P., additional, Tarot, Stéphane, additional, Tetoni, Eleni, additional, Thompson, Elizabeth J, additional, Thomson, Jim, additional, Tomassini, Lorenzo, additional, Totems, Julien, additional, Ubele, Alma Anna, additional, Villiger, Leonie, additional, von Arx, Jan, additional, Wagner, Thomas, additional, Walther, Andi, additional, Webber, Benjamin G. M., additional, Wendisch, Manfred, additional, Whitehall, Shanice, additional, Wiltshire, Anton, additional, Wing, Allison A., additional, Wirth, Martin, additional, Wiskandt, Jonathan, additional, Wolf, Kevin, additional, Worbes, Ludwig, additional, Wright, Ethan, additional, Wulfmeyer, Volker, additional, Young, Shanea, additional, Zhang, Chidong, additional, Zhang, Dongxiao, additional, Ziemen, Florian, additional, Zinner, Tobias, additional, and Zöger, Martin, additional

Published
2020
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18. EUREC4A observations from the SAFIRE ATR42 aircraft.

Author

Bony, Sandrine, Lothon, Marie, Delanoë, Julien, Coutris, Pierre, Etienne, Jean-Claude, Aemisegger, Franziska, Albright, Anna Lea, André, Thierry, Bellec, Hubert, Baron, Alexandre, Bourdinot, Jean-François, Brilouet, Pierre-Etienne, Bourdon, Aurélien, Canonici, Jean-Christophe, Caudoux, Christophe, Chazette, Patrick, Cluzeau, Michel, Cornet, Céline, Desbios, Jean-Philippe, and Duchanoy, Dominique

Subjects
MICROWAVE radiometers, DOPPLER radar, DOPPLER lidar, HYGROMETRY, RADIOMETERS, RESEARCH aircraft, HUMIDITY, FREE surfaces
Abstract

As part of the EUREC4A (Elucidating the role of cloud-circulation coupling in climate) field campaign, which took place in January and February 2020 over the western tropical Atlantic near Barbados, the French SAFIRE ATR42 research aircraft conducted 19 flights in the lower troposphere. Each flight followed a common flight pattern that sampled the atmosphere around the cloud-base level, at different heights of the subcloud layer, near the sea surface and in the lower free troposphere. The aircraft's payload included a backscatter lidar and a Doppler cloud radar that were both horizontally oriented, a Doppler cloud radar looking upward, microphysical probes, a cavity ring-down spectrometer for water isotopes, a multiwavelength radiometer, a visible camera and multiple meteorological sensors, including fast rate sensors for turbulence measurements. With this instrumentation, the ATR characterized the macrophysical and microphysical properties of trade-wind clouds together with their thermodynamical, turbulent and radiative environment. This paper presents the airborne operations, the flight segmentation, the instrumentation, the data processing and the EUREC4A datasets produced from the ATR measurements. It shows that the ATR measurements of humidity, wind and cloud-base cloud fraction measured with different techniques and samplings are internally consistent, that meteorological measurements are consistent with estimates from dropsondes launched from an overflying aircraft (HALO), and that water isotopic measurements are well correlated with data from the Barbados Cloud Observatory. This consistency demonstrates the robustness of the ATR measurements of humidity, wind, cloud-base cloud fraction and water isotopic composition during EUREC4A. It also confirms that through their repeated flight patterns, the ATR and HALO measurements provided a statistically consistent sampling of trade-wind clouds and of their environment. The ATR datasets are freely available at the locations specified in Table 11. [ABSTRACT FROM AUTHOR]

Published
2022
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19. Analysis of the size and mass properties of ice particules and study of the microphysical processes occuring in Mesoscale Convective Systems

Author

Coutris, Pierre, 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), Université Clermont Auvergne [2017-2020], Alfons Schwarzenböeck, and STAR, ABES

Subjects
Zones à fort contenu en glace, Relation masse-diamètre, Cloud microphysics, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, Hydrométéores glacés, Ice crystals, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Mesoscale convective system, Microphysique du nuage, High ice water content area, Système convectif à méso-échelle, Masssize relationship
Abstract

The detailed characterization of ice cloud microphysics is key to understand their role in theEarth’s hydrological cycle and radiation budget. The developement of atmospheric models and remote sensingalgorithms relies on parametrisations derived from in situ measurements. These measurements are also usedby the aviation industry to handle the problem of ice crystal icing. This PhD work presents an analysis of themass and size properties of ice crystals observed in high ice water content areas embedded in tropical mesoscaleconvective systems (MCS) during two airborne field campaigns of the HAIC-HIWC international project.A new approach is developped to derive mass-size relationships (m - D) from size distributions and icewater contents. The retrieval is formulated as an inverse problem which waives the power law constraint, aclassical assumption that proves to be an oversimplification when applied to heterogeneous populations of iceparticules typical of MCS anvils.The horizontal variability of size distributions and the aging of MCS anvils is described in terms of microphysicalprocesses. The importance of the aggregation growth process is emphasized as it efficiently removessmall ice particles brought into the upper troposphere by deep convection and significantly contributes to theformation of large agregates, precusor of the stratiform precipitations. The analysis of mass properties revealsthat distinctive microphysical regimes may be identified from the m-D relationship retrieved in various conditions.It paves the way toward a statistical model of the effective density of ice particles as a function of environmentalparameters., L’étude des propriétés et processus microphysiques caractérisant la phase glace permet de mieux définir le rôle des nuages dans le cycle de l’eau et sur bilan radiatif de l’atmosphère. Les modèles atmosphériques et les codes d’inversion des données de télédétection utilisent des paramétrisations établies à partir de mesures in situ. Ces mesures servent également des besoins industriels en lien avec la problématique du givrage en aéronautique. L’étude présentée se base sur les données de deux campagnes aéroportées réalisées dans le cadre de la collaboration internationale HAIC-HIWC, ciblant les zones à fort contenu en glace que l’on peut observe rau sein des systèmes convectifs à méso-échelle (MCS) tropicaux. Sur la question des relations « masse-diamètre » (m - D) d’abord, une nouvelle approche est présentée. Basée sur la résolution d’un problème inverse, elle permet de restituer la masse des cristaux à partir de mesures colocalisées classiques en s’affranchissant de la traditionnelle hypothèse de loi puissance, et montre que cette dernière ne permet pas de représenter correctement les propriétés massiques de populations de cristaux hétérogènes (morphologie et tailles différentes) typiques des MCS. La variabilité horizontale des distributions de tailles permet d’étudier le vieillissement de l’enclume d’un point de vue microphysique et de souligner le rôle essentiel du processus d’agrégation dans l’élimination des petits cristaux apportés dans la haute troposphère par la convection profonde et dans la formation d’agrégats supra-millimétriques, précurseurs glacés des précipitations stratiformes. Les relations m - D restituées permettent d’identifier des régimes microphysiques distincts et ouvre la voie aux développement d’une paramétrisation de la masse volumique des hydrométéores en fonction de critères environnementaux.

Published
2019

24. Cloud Microphysical Properties in Mesoscale Convective Systems: An Intercomparison of Three Tropical Locations

Author

Schwarzenboeck, Alfons, Coutris, Pierre, Delanoë, Julien, Protat, Alain, Dezitter, Fabien, Grandin, Alice, Strapp, John W., Lilie, Lyle E., 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), Australian Bureau of Meteorology [Melbourne] (BoM), Australian Government, Airbus [France], Met Analytics Inc. [Toronto], and Cardon, Catherine

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

International audience; Mesoscale Convective Systems are complex cloud systems which are primarily the result of specific synoptic conditions associated with mesoscale instabilities leading to the development of cumulonimbus type clouds (Houze, 2004). These systems can last several hours and can affect human societies in various ways. In general, weather and climate models use simplistic schemes to describe ice hydrometeors' properties. However, MCS are complex cloud systems where the dynamic, radiative and precipitation processes depend on spatiotemporal location in the MCS (Houze, 2004). As a consequence, hydrometeor growth processes in MCS vary in space and time, thereby impacting shape and concentration of ice crystals and finally CWC. As a consequence, differences in the representation of ice properties in models (Li et al., 2007, 2005) lead to significant disagreements in the quantification of ice cloud effects on climate evolution (Intergovernmental Panel on Climate Change Fourth Assessment Report). An accurate estimation of the spatiotemporal CWC distribution is therefore a key parameter for evaluating and improving numerical weather prediction (Stephens et al., 2002). The main purpose of this study is to show ice microphysical properties of MCS observed in three different locations in the tropical atmosphere: West-African continent, Indian Ocean, and Northern Australia. An intercomparison study is performed in order to quantify how similar or different are the ice hydrometeors' properties in these three regions related to radar reflectivity factors and temperatures observed in respective MCS.

Published
2017

26. Variations of Ice Microphysical Properties in Tropical MCS Using Cloud In-Situ Data and Corresponding Radar Reflectivity Profiles

Author

Fontaine, Emmanuel, Leroy, Delphine, Schwarzenboeck, Alfons, Coutris, Pierre, Delanoë, Julien, Protat, Alain, Dezitter, Fabien, Calmels, Alice, Strapp, John Walter, Lilie, Lyle, Minnis, Patrick, Yost, Christopher R., 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), Australian Bureau of Meteorology [Melbourne] (BoM), Australian Government, Airbus [France], Met Analytics Inc. [Toronto], Science Engineering Associates Inc., NASA Langley Research Center [Hampton] (LaRC), Science Systems and Applications, Inc. [Lanham] (SSAI), Cardon, Catherine, and Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

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

International audience; Mesoscale convective systems (MCS) can last several hours or more and affect human societies in different ways. In order to predict and identify hazardous weather (e. g. in view of aviation safety) linked to MCS, numerical weather forecast and active/passive remote sensing products are currently the most useful tools. A major obstacle to increasing the accuracy of those tools is the fact that cumulonimbus clouds in MCS are composed of liquid droplets and ice hydrometeors (ice crystals); the latter have complex shapes based on diffusional growth, aggregation, and riming, which complicates the interpretation of remote sensing products and increases the uncertainties in numerical weather forecast. In this context, the study presented here investigates the properties of ice hydrometeors in MCS as a function of temperature and horizontal distance from the convective core. For this purpose, ice hydrometeor images, bulk TWC, and simultaneously measured radar reflectivity factors from three airborne campaigns in tropical MCS have been used. The underlying scope of producing these results is to improve the retrieval of MCS microphysical properties from satellite products and also improve cloud parameterizations in numerical weather prediction models.

Published
2016

27. Simulations of Radar Reflectivity Factors at 94GHz: Ice Crystal Approximation with Oblate Spheroids

Author

Fontaine, Emmanuel, Leroy, Delphine, Schwarzenboeck, Alfons, Coutris, Pierre, Delanoë, Julien, Protat, Alain, Dezitter, Fabien, Calmels, Alice, Strapp, John Walter, Lilie, Lyle, 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), Australian Bureau of Meteorology [Melbourne] (BoM), Australian Government, Airbus [France], Met Analytics Inc. [Toronto], Science Engineering Associates Inc., 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
[SDU.STU.ME] Sciences of the Universe [physics]/Earth Sciences/Meteorology, Astrophysics::Earth and Planetary Astrophysics, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, Physics::Atmospheric and Oceanic Physics
Abstract

International audience; This study explores the potential of simulating cloud radar reflectivity factors (RRF) at 94GHz from a combination of cloud particle 2D images from optical array probes and bulk condensed water content, simultaneously measured during the first aircraft field campaign of the High Altitude Ice Crystals (HAIC) / High Ice Water Content (HIWC) international project performed out of Darwin in 2014. Within these simulations, ice crystals are approximated by oblate spheroids without à priori assumptions on mass-size relationships of ice crystals. The method allows calculating time dependent ranges of radar reflectivity factors deduced for given size distributions of hydrometeors, averaged over 5 seconds. Ice hydrometeor size distributions and shapes (flattening parameter for oblate spheroids) are deduced from 2D images, and are subsequently used to constrain the ice particle density (thereby matching simulated and corresponding measured radar reflectivity factors). Finally, uncertainties in oblate spheroid approximations are studied in order to demonstrate some limitations of this method.

Published
2016

29. 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
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