Combined impacts of convection and microphysics parameterizations on the simulations of precipitation and cloud properties over Asia

Abstract

Convection and microphysics parameterization schemes (i.e. CPS and MPS) are two important components related to the precipitation and cloud simulations in climate models, and one parameterization's impacts on the results can be dependent on the treatments in the other one. This study investigates the individual and combined impacts of CPS and MPS on the precipitation and cloud simulations over Asia based on nine regional model experiments using combinations of three CPSs of the Kain–Fritsch (KF), Zhang–McFarlane (ZM), and Grell 3D ensemble (G3), and three MPSs of the WRF double-moment 5-class (WDM5), WRF double-moment 6-class (WDM6), and Morrison double-moment (MORR). We first evaluate the simulated precipitation and find the experiment configured with the ZM CPS and MORR MPS performs the best when considering both the precipitation mean magnitude and spatial pattern. The sensitivity analysis results show that enhanced convection due to changing the CPS can cause strengthened or weakened stratiform processes, depending on the height of convective detrainments relative to that of convective drying, which is different among CPSs. In general, the CPS impacts on precipitation and clouds are larger when associating with the MORR MPS than with the other two MPSs as the former simulates more clouds and exhibits larger sensitivity of stratiform-type drying to convective detrainments. The MPS impacts on the precipitation and cloud simulations are also highly related to the CPS's behavior in simulating ice detrainments. Compared to the sum of the individual effects of CPS and MPS, simultaneously changing the two parameterizations causes considerably larger impacts on the precipitation and cloud simulations, suggesting the strong nonlinear interaction between the CPS and MPS.