Responses of the Tropical Atmospheric Circulation to Climate Change and Connection to the Hydrological Cycle

Change of the position and intensity of the intertropical convergence zone (ITCZ) and the sea surface temperature (SST) warming patterns are both prevailing topics of climate change dynamics. However, their mechanisms were investigated separately, though they can be seen as two sides of a coin. In state-of-the-art climate model projections, we found that the North Pacific ITCZ and warm pool are predicted to widen with weakened horizontal SST gradient, while the South Pacific convergence zone shrinks in the southern boundary. We diagnose the thermodynamic mechanisms contributing to this change, quantifying the effects of air-sea interactions and ocean heat flux. The influence of ocean surface flux such as short- and long-wave radiation, latent and sensible heating is considered, with special interest on the surface air temperature change caused by the mean advection of stratification change effect, and the consequences on atmospheric property like relative humidity.