Cooling and Sinking of the Atlantic Water in the Eurasian Basin Since 1990s

Abstract Atlantic Water (AW) is the primary oceanic heat source for the Arctic Ocean and provides significant heat for sea ice melting. Despite recent Arctic Ocean warming being a hot topic of discussion, we find that the AW core has been cooling and sinking in the Eurasian Basin according to observational data from the past three decades. This phenomenon can be attributed to the volume decrease and salinity increase of the Fram Strait inflow. Specifically, the Fram Strait inflow has decreased in volume by 28% (0.32 Sv/decade, responsible for AW cooling), while its salinity has increased (∼0.1 psu, resulting in the AW sinking by several tens of meters) over recent decades. Diminished Fram Strait inflow reduced the oceanic heat entering the Eurasian Basin, resulting in a lower heat content in the AW layer and potentially reducing upward heat transport, thereby contributing to the recent moderation of sea ice melting.