Large Scale Salinity Anomaly Has Triggered the Recent Decline of Winter Convection in the Greenland Sea
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...
Published in: | Geophysical Research Letters |
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Main Authors: | , , |
Other Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2023
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Subjects: | |
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 |
Summary: | 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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