Rapid subsurface warming in the subpolar North Atlantic from freshening.

Abstract

Over recent decades, the Arctic has warmed four times faster than the global average, associated with a decline in sea ice and accelerating Greenland Ice Sheet mass loss, which has contributed to episodic freshening of the subpolar North Atlantic. Here, we show that a 0.05 Sv North Atlantic meltwater flux induces  ~ 1°C subsurface warming within a decade in Baffin Bay, Hudson Strait, and along Greenland's southern and western coasts. This warming arises from enhanced stratification, weakened deep convection in the subpolar gyre, and a weaker Labrador Current. Freshening also alters horizontal density gradients, strengthening cyclonic circulation in the Nordic Seas and causing transient regio..