Further study on the effect of buffer zone size on regional climate modeling

In this study, the effect of buffer zone size on the performance of a regional climate model (RCM) was investigated. In contrast to carrying out simulations where the buffer zone expands inward, numerical experiments were performed with the buffer zone expanded outward, which ensured an objective comparison on the effect of buffer zone sizes. Case simulations on the abnormal 1998 East Asian summer monsoon demonstrated that an RCM’s performance depended on the outward expansion of the buffer zone. Moreover, a broader buffer zone is able to improve large-scale circulation simulation in the upper troposphere; however, a narrower buffer zone shows better performance in the middle and lower troposphere. Numerical experiments show that the performance of RCMs in simulating the seasonal evolution of rainbands over eastern China is not completely consistent with that of the western Pacific subtropical high (WPSH). A possible reason why the configuration with the buffer zone expanding inward can improve the extension/withdrawal of the summer monsoon and the associated precipitation evolution over eastern China is discussed.