The role of mesoscale ocean currents in the mixed-layer heat budget and air-sea coupling in the Southern Ocean
In this study, the importance of mesoscale advection in the OML heat budget and air-sea coupling is explored using a regional high-resolution atmosphere-ocean coupled model with a realistic atmospheric component and an oceanic model of a zonal flow. The results show that the OML heat budget is dominated by the heat advection by both the large-scale and mesoscale currents and by the heat exchanges at the base of OML. On average, the OML-integrated mesoscale heat advection is shown to induce SSTAs, while the large-scale heat advection acts to weaken them. The negative correlation between SSTAs and air-sea heat flux anomalies further demonstrates that these mesoscale current-induced SSTAs drive the anomalous air-sea heat exchange, with the warmer SSTAs releasing heat to the atmosphere, and vice versa. Therefore, neglecting the mesoscale currents in low-resolution climate model may lead to errors in the simulated SST variability and air-sea heat exchange.