Large Scale Salinity Anomaly Has Triggered the Recent Decline of Winter Convection in the Greenland Sea

Type Article
Date 2023-11
Language English
Author(s) Almeida LucasORCID1, Kolodziejczyk NicolasORCID1, Lique CamilleORCID2
Affiliation(s) 1 : University Brest CNRS Ifremer IRD Laboratoire d'Océanographie Physique et Spatiale (LOPS) IUEM Plouzané France
2 : University Brest CNRS Ifremer IRD Laboratoire d'Océanographie Physique et Spatiale (LOPS) IUEM Plouzané France
Source Geophysical Research Letters (0094-8276) (American Geophysical Union (AGU)), 2023-11 , Vol. 50 , N. 21 , P. e2023GL104766 (10p.)
DOI 10.1029/2023GL104766
Keyword(s) convection, physical oceanography, climate system, Nordic Seas, Greenland Sea, oceanography
Abstract

The Greenland Sea is a key region for open ocean convection and ventilation, which exhibit a large variability with periods of strong convection and shutdowns. After a long period of weak winter convection (from the 1970s to the early 1990s), a recovery has been reported, beginning in the 1990s and intensifying in the early 2000s until 2013. Using ISAS, an optimal interpolation product based on Argo observations, we document a recent significant weakening of deep convection between 2014 and 2020, accompanied by a continuous warming of the mixed layer but also a freshening after 2014. These hydrographic changes likely increase the ocean stratification and precondition the shutdown of winter convection. We suggest that these property changes result from a shift of the large scale atmospheric circulation, affecting the source of Atlantic Water to the Nordic seas, causing a freshening of about −0.1 g kg−1 that spreads into the Greenland Sea.

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