Session: Cross-cutting Group 2 (Paleovar, Past to future, Data assimilation)
Author: Yong Sun / email@example.com / Institute of Atmospheric Physics, Chinese Academy of Sciences
Co-author: Gilles Ramstein, Laboratoire des Sciences du Climat et de l'Environnement;
Ning Tan, Laboratoire des Sciences du Climat et de l'Environnement;
Tianjun Zhou, Institute of Atmospheric Physics, Chinese Academy of Sciences;
In this study, moisture budget analysis and moist static energy (MSE) are applied to investigate the drivers and mechanisms of East Asian summer monsoon (EASM) precipitation in the mid-Pliocene and RCP4.5 scenario. The enhancement of EASM precipitation is a common feature in both warmer climates. By diagnosing moisture budget analysis, it was found that thermodynamic component contributes more than dynamical contribution to EASM precipitation in both warmer climates, which essentially represents the increasing response of EASM precipitation to the past and future warming.
MSE is used to reveal the dynamical mechanism responsible for the EASM precipitation enhancement. One mechanism identified by MSE is zonal thermal contrast enhancement and the other is stationary meridional velocity. The former can affect EASM precipitation via strengthening of large-scale circulation associated moisture transport into EASM domain. while the latter can exert EASM precipitation through modulating the local physical processes associated with moisture convergence in mid-Pliocene and divergence in RCP4.5 scenario, which is possible reason to explain why projected EASM precipitation with higher than mid-Pliocene CO2 level but precipitation increase less than mid-Pliocene. Nevertheless, mid-Pliocene offers an analogue to understand the EASM dynamics in the future scenario.