Interdecadal Change of the Winter-Spring Tropospheric Temperature Over Asia and its Impact on the South China Sea Summer Monsoon Onset

The interdecadal change of the winter-spring tropospheric temperature over Asia and its impact on South China Sea summer monsoon (SCSSM) onset are investigated in this study. SCSSM experiences a significant advance around mid-1990s, which is attributed to positive anomaly meridional gradient mid-upper troposphere May region. This can be traced back previous winter spring, mainly associated with warming East Asian subtropics. During anomalous seasonal evolution subtropical temperature, advection warm by climatological mean wind overtakes effects adiabatic cooling diabatic cooling, leading net winter. In heating caused subsidence flow cannot offset cold resulting cooling. However, spring not strong enough winter, preserving an late spring. provides favorable condition for onset. Both observational analyses numerical experiments suggest that atmospheric thermodynamic processes winter−spring related tropical western Pacific. enhanced convection condensation regions from Philippines, forced Pacific warming, stimulates anticyclone upper whole Asia.