Atmospheric and Surface Processes, and Feedback Mechanisms Determining Arctic Amplification: A Review of First Results and Prospects of the (AC)3 Project
Manfred Wendisch, Marlen Brückner, Susanne Crewell, Angela Ehrlich, Justus Notholt, Christof Lüpkes, Andreas Macke, John P. Burrows, Annette Rinke, Johannes Quaas, Marion Maturilli, Vera Schemann, Matthew D. Shupe, Elisa F. Akansu, Carola Barrientos Velasco, Konrad Bärfuss, Anne‐Marlene Blechschmidt, Karoline Block, Ilias Bougoudis, Heiko Bozem, Christine Böckmann, Astrid Bracher, Hélène Bresson, Lutz Bretschneider, Matthias Buschmann, Dmitry Chechin, Jan Chylik, Sandro Dahlke, Hartwig Deneke, Klaus Dethloff, Tobias Donth, Wolfgang Dorn, Régis Dupuy, Kerstin Ebell, Ulrike Egerer, Ronny Engelmann, Oliver Eppers, R. Gerdes, Rosa Gierens, Irina Gorodetskaya, Matthias Gottschalk, Hannes Griesche, Vladimir M. Gryanik, Dörthe Handorf, Barbara Altstädter, Jörg Hartmann, Markus Hartmann, Bernd Heinold, Andreas Herber, Hartmut Herrmann, Georg Heygster, Ines Höschel, Zerlina Hofmann, Jens Hölemann, Anja Hünerbein, Soheila Jafariserajehlou, Evelyn Jäkel, Christoph Jacobi, Markus Janout, Friedhelm Jansen, Olivier Jourdan, Zsófia Jurányi, Heike Kalesse‐Los, Torsten Kanzow, R. Käthner, Leif-Leonard Kliesch, Marcus Klingebiel, Erlend M. Knudsen, T. Kovács, W. Körtke, Daniela Krampe, Jonas Kretzschmar, Daniel Kreyling, Birte Solveig Kulla, Daniel Kunkel, Astrid Lampert, Melanie Lauer, Luca Lelli, Annakaisa von Lerber, Olivia Linke, Ulrich Löhnert, Michael Lonardi, S. N. Losa, Martin Lösch, Maximilian Maahn, Mario Mech, Linlu Mei, Stephan Mertes, Enrico P. Metzner, Daniel Mewes, Janosch Michaelis, Guillaume Mioche, Massimo Moser, Konstantina Nakoudi, Roel Neggers, Roland Neuber, Tatiana Nomokonova, Julia Oelker, Iris Papakonstantinou Presvelou, Falk Pätzold
Abstract
Abstract Mechanisms behind the phenomenon of Arctic amplification are widely discussed. To contribute to this debate, the (AC) 3 project was established in 2016 ( www.ac3-tr.de/ ). It comprises modeling and data analysis efforts as well as observational elements. The project has assembled a wealth of ground-based, airborne, shipborne, and satellite data of physical, chemical, and meteorological properties of the Arctic atmosphere, cryosphere, and upper ocean that are available for the Arctic climate research community. Short-term changes and indications of long-term trends in Arctic climate parameters have been detected using existing and new data. For example, a distinct atmospheric moistening, an increase of regional storm activities, an amplified winter warming in the Svalbard and North Pole regions, and a decrease of sea ice thickness in the Fram Strait and of snow depth on sea ice have been identified. A positive trend of tropospheric bromine monoxide (BrO) column densities during polar spring was verified. Local marine/biogenic sources for cloud condensation nuclei and ice nucleating particles were found. Atmospheric–ocean and radiative transfer models were advanced by applying new parameterizations of surface albedo, cloud droplet activation, convective plumes and related processes over leads, and turbulent transfer coefficients for stable surface layers. Four modes of the surface radiative energy budget were explored and reproduced by simulations. To advance the future synthesis of the results, cross-cutting activities are being developed aiming to answer key questions in four focus areas: lapse rate feedback, surface processes, Arctic mixed-phase clouds, and airmass transport and transformation.