Exceptional Air Mass Transport and Dynamical Drivers of an Extreme Wintertime Arctic Warm Event

• Published in: Geophysical Research Letters
• Main Authors: Binder, Hanin, Boettcher, Maxi, Grams, Christian M., Joos, Hanna, Pfahl, Stephan, Wernli, Heini
• Other Authors: Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), 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)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: extreme weather; sea ice melt; Lagrangian perspective; Arctic; dynamics; diabatic processes; [SDU]Sciences of the Universe [physics]; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Sea ice
• Online Access: https://hal-insu.archives-ouvertes.fr/insu-03727036; https://hal-insu.archives-ouvertes.fr/insu-03727036/document; https://hal-insu.archives-ouvertes.fr/insu-03727036/file/Geophysical%20Research%20Letters%20-%202017%20-%20Binder%20-%20Exceptional%20Air%20Mass%20Transport%20and%20Dynamical%20Drivers%20of%20an%20Extreme.pdf; https://doi.org/10.1002/2017GL075841

International audience At the turn of the years 2015/2016, maximum surface temperature in the Arctic reached record-high values, exceeding the melting point, which led to a strong reduction of the Arctic sea ice extent in the middle of the cold season. Here we show, using a Lagrangian method, that a combination of very different airstreams contributed to this event: (i) warm low-level air of subtropical origin, (ii) initially cold low-level air of polar origin heated by surface fluxes, and (iii) strongly descending air heated by adiabatic compression. The poleward transport of these warm airstreams occurred along an intense low-level jet between a series of cyclones and a quasi-stationary anticyclone. The complex 3-D configuration that enabled this transport was facilitated by continuous warm conveyor belt ascent into the upper part of the anticyclone. This study emphasizes the combined role of multiple transport processes and transient synoptic-scale dynamics for establishing an extreme Arctic warm event.