Coupled atmosphere–ocean observations of a cold-air outbreak and its impact on the Iceland Sea
| Autor: | Ian A. Renfrew, Jie Huang, Stefanie Semper, Christopher Barrell, Annick Terpstra, Robert S. Pickart, Kjetil Våge, Andrew D. Elvidge, Thomas Spengler, Anna‐Marie Strehl, Alexandra Weiss |
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| Jazyk: | angličtina |
| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) Quarterly Journal of the Royal Meteorological Society |
| Popis: | Marine cold-air outbreaks (CAO) are vigorous equatorward excursions of coldair over the ocean, responsible for the majority of wintertime oceanic heat lossfrom the subpolar seas of the North Atlantic. However, the impact of individualCAO events on the ocean is poorly understood. Here we present the first coupledobservations of the atmosphere and ocean during a wintertime CAO event,between 28 February and 13 March 2018, in the subpolar North Atlantic region.Comprehensive observations are presented from five aircraft flights, a researchvessel, a meteorological buoy, a subsurface mooring, an ocean glider, and anArgo float. The CAO event starts abruptly with substantial changes in temperature,humidity and wind throughout the atmospheric boundary layer. The CAOiswell mixed vertically and, away from the sea-ice edge, relatively homogeneousspatially. During the CAO peak, higher sensible heat fluxes occupy at least thelowest 200m of the atmospheric boundary layer, while higher latent heat fluxesare confined to the surface layer. The response of the ocean to the CAO is spatiallydependent. In the interior of the Iceland Sea the mixed layer cools, while inthe boundary current region itwarms. In both locations, the mixed layer deepensand becomes more saline. Combining our observations with one-dimensionalmixed-layer modelling, we show that in the interior of the Iceland Sea, atmosphericforcing dominates the ocean response. In contrast, in the boundarycurrent region lateral advection and mixing counteract the short-term impact ofthe atmospheric forcing. Timeseries observations of the late-winter period illustratea highly variable ocean mixed layer, with lateral advection and mixing oftenmasking the ocean’s general cooling and deepening response to individual CAOevents. The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) |
| Databáze: | OpenAIRE |
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