CAM6 Simulation of Mean and Extreme Precipitation Over Asia: Sensitivity to Upgraded Physical Parameterizations and Higher Horizontal Resolution
Because CESM2/CAM6 is participating in the CMIP6 and is likely to be adopted in many future studies, its simulation fidelity needed to be thoroughly examined. This study evaluates the performance of CAM6 in both low (1°) and high (0.25°) resolution configurations compared to various observational and reanalysis datasets of precipitation over Asia.
Prognostic treatment of precipitation processes and the new microphysics module lead to a better representation of climatological mean and extreme precipitation over Asia, heaviest precipitation events, diurnal cycle of precipitation rates over most of Asia, and probability density distributions of daily precipitation over Tibet, Korea, Japan, and Northern China. Higher horizontal resolution leads to better representation of mean and extreme precipitation over Northern China. Impacts of both new physics and parameterizations and higher resolution are regionally dependent with improvement in some regions and degradation in others.
CAM6 is found to better represent many aspects of precipitation over Asia compared to CAM5. These results can be used as a baseline analysis for future studies using the CAM6 (CMIP6) version of the CESM.