Spatiotemporally unified air-sea interaction in tropical oceans

The spatiotemporal variation in tropical air-sea interaction is investigated by applying a simple model that considers the fundamental dynamics in tropical oceans. The model decomposes sea surface temperature anomaly (SSTA) variation into a series of spatial modes that oscillates with their natural frequencies. The results suggest that the first mode associates with the dipole-like SSTA variation between the western and the eastern coast, such as EP El Niño, the Atlantic Niño, and IOD; whereas the second mode associates with the tripole-like SSTA pattern among the central and eastern, western coast, such as CP El Niño and minor SSTA variations in the tropical Atlantic and Indian Ocean. Each mode oscillates with its natural frequency that depends on the strength of air-sea coupling and the basin size. The model provides a systematic framework for the comprehensive understanding of the complex air-sea interaction in tropical oceans.