Overview: quasi-Lagrangian observations of Arctic airmass transformations – introduction and initial results ofthe HALO–(AC)3 aircraft campaign

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Wendisch, Manfred, Crewell, Susanne, Ehrlich, André, Herber, Andreas, Kirbus, Benjamin, Lüpkes, Christof, Mech, Mario, Abel, Steven, J, Akansu, Elisa, F, Ament, Felix, Aubry, Clémantyne, Becker, Sebastian, Borrmann, Stephan, Bozem, Heiko, Brückner, Marlen, Clemen, Hans-Christian, Dahlke, Sandro, Dekoutsidis, Georgios, Delanoë, Julien, De La Torre Castro, Elena, Dorff, Henning, Dupuy, Regis, Eppers, Oliver, Ewald, Florian, George, Geet, Gorodetskaya, Irina, V, Grawe, Sarah, Groß, Silke, Hartmann, Jörg, Henning, Silvia, Hirsch, Lutz, Jäkel, Evelyn, Joppe, Philipp, Jourdan, Olivier, Jurányi, Zsofia, Karalis, Michail, Kellermann, Mona, Klingebiel, Marcus, Lonardi, Michael, Lucke, Johannes, Luebke, Anna, Maahn, Maximilian, Maherndl, Nina, Maturilli, Marion, Mayer, Bernhard, Mayer, Johanna, Mertes, Stephan, Michaelis, Janosch, Michalkov, Michel, Mioche, Guillaume, Moser, Manuel, Müller, Hanno, Neggers, Roel, Ori, Davide, Paul, Daria, Paulus, Fiona, Pilz, Christian, Pithan, Felix, Pöhlker, Mira, Pörtge, Veronika, Ringel, Maximilian, Risse, Nils, Roberts, Gregory, C, Rosenburg, Sophie, Röttenbacher, Johannes, Rückert, Janna, Schäfer, Michael, Schaefer, Jonas, Schemann, Vera, Schirmacher, Imke, Schmidt, Jörg, Schmidt, Sebastian, Schneider, Johannes, Schnitt, Sabrina, Schwarz, Anja, Siebert, Holger, Sodemann, Harald, Sperzel, Tim, Spreen, Gunnar, Stevens, Bjorn, Stratmann, Frank, Svensson, Gunilla, Tatzelt, Christian, Tuch, Thomas, Vihma, Timo, Voigt, Christiane, Volkmer, Lea, Walbröl, Andreas, Weber, Anna, Wehner, Birgit, Wetzel, Bruno, Wirth, Martin, Zinner, Tobias
• Other Authors: Leipziger Institut für Meteorologie (LIM), Leipzig University / Universität Leipzig, Institut für Geophysik und Meteorologie Köln (IGN), Universität zu Köln = University of Cologne, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine (AWI), Helmholtz-Gemeinschaft = Helmholtz Association, United Kingdom Met Office Exeter, Leibniz-Institut für Troposphärenforschung (TROPOS), Meteorologisches Institut Hamburg, Universität Hamburg (UHH), 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), DLR Institut für Physik der Atmosphäre = DLR Institute of Atmospheric Physics (IPA), Deutsches Zentrum für Luft- und Raumfahrt Oberpfaffenhofen-Wessling (DLR), Abteilung für Partikelchemie Mainz, Max-Planck-Institut für Chemie (MPIC), Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Institut für Physik der Atmosphäre Mainz (IPA), Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Faculty of Aerospace Engineering Delft, Delft University of Technology (TU Delft), 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), Max-Planck-Institut für Meteorologie (MPI-M), Max-Planck-Gesellschaft, Centro de Estudos do Ambiente e do Mar (CESAM), Universidade de Aveiro, Department of Meteorology Stockholm (MISU), Stockholm University, Bolin Centre for Climate Research, Extreme Environments Research Laboratory (EERL), Ecole Polytechnique Fédérale de Lausanne (EPFL), Meteorologisches Institut München (MIM), Ludwig Maximilian University Munich = Ludwig Maximilians Universität München (LMU), Deutscher Wetterdienst Hamburg (DWD), Scripps Institution of Oceanography (SIO - UC San Diego), University of California San Diego (UC San Diego), University of California (UC)-University of California (UC), Institut für Umweltphysik Bremen (IUP), Universität Bremen, Laboratory for Atmospheric and Space Physics Boulder (LASP), University of Colorado Boulder, Geophysical Institute Bergen (GFI / BiU), University of Bergen (UiB), Bjerknes Centre for Climate Research (BCCR), Department of Biological Sciences Bergen (BIO / UiB), University of Bergen (UiB)-University of Bergen (UiB), Finnish Meteorological Institute (FMI)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2024
• Subjects: [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Arctic; Greenland; Fram Strait; Global warming; Sea ice
• Online Access: https://insu.hal.science/insu-04522598; https://insu.hal.science/insu-04522598v2/document; https://insu.hal.science/insu-04522598v2/file/acp-24-8865-2024.pdf; https://doi.org/10.5194/acp-24-8865-2024

International audience Global warming is amplified in the Arctic. However, numerical models struggle to represent key pro-cesses that determine Arctic weather and climate. To collect data that help to constrain the models, the HALO–(AC)3 aircraft campaign was conducted over the Norwegian and Greenland seas, the Fram Strait, and the centralArctic Ocean in March and April 2022. The campaign focused on one specific challenge posed by the models,namely the reasonable representation of transformations of air masses during their meridional transport into andout of the Arctic via northward moist- and warm-air intrusions (WAIs) and southward marine cold-air outbreaks(CAOs). Observations were made over areas of open ocean, the marginal sea ice zone, and the central Arcticsea ice. Two low-flying and one long-range, high-altitude research aircraft were flown in colocated formationwhenever possible. To follow the air mass transformations, a quasi-Lagrangian flight strategy using trajectorycalculations was realized, enabling us to sample the same moving-air parcels twice along their trajectories. Sevendistinct WAI and 12 CAO cases were probed. From the quasi-Lagrangian measurements, we have quantified thediabatic heating/cooling and moistening/drying of the transported air masses. During CAOs, maximum valuesof 3 K h−1 warming and 0.3 g kg−1 h−1 moistening were obtained below 1 km altitude. From the observations ofWAIs, diabatic cooling rates of up to 0.4 K h−1 and a moisture loss of up to 0.1 g kg−1 h−1 from the ground toabout 5.5 km altitude were derived. Furthermore, the development of cloud macrophysical (cloud-top height andhorizontal cloud cover) and microphysical (liquid water path, precipitation, and ice index) properties along thesouthward pathways of the air masses were documented during CAOs, and the moisture budget during a specificWAI event was estimated. In addition, we discuss the statistical frequency of occurrence of the different thermo-dynamic phases of Arctic low-level clouds, the interaction of Arctic ...