Testing the influence of western Pacific subtropical high...

Abstract

In this paper, two seasonal scale simulations were conducted for the abnormal climate event in China in the summer of 1998 using a regional climate model (RegCM3). One is the control run, the other is nudging run, which was performed for zonal and meridional wind components, temperature, and humidity data for the region east of 120° E in the model domain to ensure that the simulated activity of western Pacific subtropical high (WPSH) in summer followed those of reanalysis data, while the interaction between the WPSH and the surrounding circulation systems was still maintained partially. Comparisons between the simulated regional circulation systems and the extension/withdrawal of the rain belt over eastern China as well as the activity of the WPSH were carried out. The results show that the relationship between the precipitation over eastern China and WPSH can be reproduced well in the nudging run. However, though the extension/withdrawal of the rain belt over eastern China is mainly dominated by that of WPSH, as pointed out by so many research works, the detailed precipitation scenario is not solely determined by the intensity and position of WPSH, and the precipitation discrepancy between simulation and observation is significant to some extent, which suggests that it is important to improve the precipitation physical process of the model in simulating the detailed precipitation scenario over eastern China.