What causes the location of the air-sea turbulent heat flux maximum over the Labrador Sea?

The Labrador Sea is a region of climatic importance as a result of the occurrence of oceanic wintertime convection, a process that is integral to the Atlantic Meridional Overturning Circulation. This process requires large air-sea heat fluxes that result in a loss of surface buoyancy, triggering convective overturning of the water column. The Labrador Sea wintertime turbulent heat flux maximum is situated downstream of the ice edge, a location previously thought to be causal. Here we show that there is considerable similarity in the characteristics of the regional mean atmospheric circulation and high heat flux events over the Labrador Sea during early winter, when the ice is situated to the north, and midwinter, when it is near the region of maximum heat loss. This suggests that other factors, including the topography of the nearby upstream and downstream landmasses, contribute to the location of the heat flux maximum.