Surface Heat Flux Induced by Mesoscale Eddies Cools the Kuroshio‐Oyashio Extension Region

Sea surface temperature (SST) is a key player in the air‐sea interaction, influencing storm tracks, atmospheric circulation, and climate modes. Although prevailing theories attribute variations of large‐scale SST to atmosphere forcing and ocean internal dynamics, we find that sea surface heat flux anomalies induced by mesoscale eddies exert significant influences on the upper‐ocean heat budget in the Kuroshio‐Oyashio extension region. Despite making nearly no contribution to the net heat exchange at the air‐sea interface, the eddy‐induced heat flux anomalies weaken the thermal stratification in the upper ocean and result in pronounced sea surface cooling. The underlying dynamics is the efficient dissipation of eddy potential energy by eddy‐induced heat flux anomalies. This makes the conversion of eddy potential energy to eddy kinetic energy significantly reduced, corresponding to a weaker eddy‐induced restratification flux. The finding complements the existing theories on large‐scale SST dynamics and has important implications for understanding extratropical climate variability.