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

• Published in: Geophysical Research Letters
• Main Authors: Almeida, Lucas, Kolodziejczyk, Nicolas, Lique, Camille
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union (AGU) 2023
• Subjects: convection; physical oceanography; climate system; Nordic Seas; Greenland Sea; oceanography; Greenland
• Online Access: https://archimer.ifremer.fr/doc/00859/97063/105818.pdf; https://doi.org/10.1029/2023GL104766; https://archimer.ifremer.fr/doc/00859/97063/

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.