Ocean-atmosphere coupling regimes in the tropical area

Tropical ocean-atmosphere coupling plays a pivotal role in regulating the global climate system. Variability and mechanisms of the coupling exhibit significant regional differences due to variations in the background states and thermodynamic processes across the tropical basins. While previous studies mostly focused on the specific time scales and localized regions, a broader view of the tropical air-sea coupling “picture” remains incomplete. This project first utilizes an energy balance model of the coupled ocean-atmosphere system to diagnose the coupling characteristics for each tropical grid point across timescales through the “heat flux—sea surface temperature” relationship. Subsequently, a clustering algorithm is used to classify spatial differences into distinct coupling regimes. Finally, decomposition of the flux calculation is applied to identify critical variables and processes underlying each regime. This approach progressively reveals the mechanisms behind the regional differences in tropical ocean-atmosphere coupling features. Our findings also highlight that current high-resolution climate models still face challenges in accurately reproducing the coupling characteristics of some regimes, which would further limit the accuracy of climate simulation and prediction.