Contrasting Air-Sea Coupling Processes of Conventional and Unconventional Oceanic Eddies in the East China Sea during Winter

Both conventional (cold cyclonic and warm anticyclonic) and unconventional (warm cyclonic and cold anticyclonic) oceanic eddies are frequently observed near the Kuroshio axis in the East China Sea, as identified from daily oceanic reanalysis datasets during winter months since 1993. These four types of eddies exhibit remarkably different temporal evolution characteristics and spatial distribution patterns, along with contrasting 3D thermal and dynamic structures. Each eddy type demonstrates significantly varying intensities in multiple oceanic and atmospheric physical quantities, including sea surface temperature (SST) anomalies, vorticity fields, and heat flux exchanges. In particular, the air-sea coupling relationships presented by the correlations between SST and air-sea turbulent heat flux over the conventional and unconventional eddies exhibit opposite characteristics, which are likely to contribute to longer (shorter) lifespans of conventional (unconventional) eddies. In addition, the difference in air-sea heat flux anomalies associated with four eddy types determines the corresponding responses of the lower and middle atmosphere over the oceanic eddies, including the 3D air temperature, horizontal wind, vertical velocity at various pressure levels and the atmospheric boundary layer height.