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
• Other Authors: Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: [SDU]Sciences of the Universe [physics]; Greenland; Greenland Sea; Nordic Seas
• Online Access: https://hal.science/hal-04334640; https://hal.science/hal-04334640/document; https://hal.science/hal-04334640/file/Geophysical%20Research%20Letters%20-%202023%20-%20Almeida%20-%20Large%20Scale%20Salinity%20Anomaly%20Has%20Triggered%20the%20Recent%20Decline%20of%20Winter.pdf; https://doi.org/10.1029/2023GL104766

International audience 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.