Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Oceanстатья
Статья опубликована в высокорейтинговом журнале
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 20 января 2021 г.
Аннотация:A 15-yr duration record of mooring observations from the eastern (.708E) Eurasian Basin (EB) of theArctic Ocean is used to show and quantify the recently increased oceanic heat flux from intermediate-depth(;150–900 m) warm Atlantic Water (AW) to the surface mixed layer and sea ice. The upward release of AW heat isregulated by the stability of the overlying halocline, which we show has weakened substantially in recent years.Shoaling of the AW has also contributed, with observations in winter 2017–18 showing AW at only 80 m depth, justbelow the wintertime surface mixed layer, the shallowest in our mooring records. The weakening of the halocline forseveral months at this time implies that AW heat was linked to winter convection associated with brine rejectionduring sea ice formation. This resulted in a substantial increase of upward oceanic heat flux during the winter season,from an average of 3–4W m22 in 2007–08 to .10W m22 in 2016–18. This seasonal AW heat loss in the eastern EB isequivalent to a more than a twofold reduction of winter ice growth. These changes imply a positive feedback asreduced sea ice cover permits increased mixing, augmenting the summer-dominated ice-albedo feedback.