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CR prepress abstract   -  DOI:

Daily precipitation characteristics of RegCM4 and WRF in China and their interannual variations

Xianghui Kong, Aihui Wang*, Xunqiang Bi, Jiangfeng Wei

*Corresponding author:

ABSTRACT: To evaluate and clarify the daily precipitation characteristics (i.e. amount, frequency, and intensity) of the regional climate models (RCMs) in China, long-term simulations were carried out using RegCM 4.5 and WRF-ARW 3.6, which were nested within the ECMWF’s 20th century reanalysis (ERA-20C) between 1901 and 2010. The two RCMs were initially run at a resolution of 50 km. Analyses mainly compared the model simulated climatic means and interannual variations of precipitation characteristics with those of dense and high-quality station observations (STN) from 1961 to 2010. Both models satisfactorily reproduced the seasonal mean of precipitation amount, but they overestimated its frequency and underestimated its intensity. Extreme rainfall frequency was also underestimated by both RCMs. In winter (December-January-February), the interannual variabilities in dry days, light precipitation and moderate precipitation were well represented by both models. However, they poorly reproduced the counterparts of extreme precipitation in winter. In summer (June-July-August), the two RCMs had good performance in simulating the interannual variability of extreme precipitation. Comparably, RegCM outperformed WRF in reproducing the spatial patterns of precipitation amount, interannual variations in extreme precipitation and rain events. By contrast, WRF has overall better quality for the representation of precipitation frequency in different subregions. Moreover, when the horizontal resolution of RegCM was increased from 50 km to 25 km, there was slight improvement in the precipitation amount and intensity. Our results show that RCMs generally reproduce actual climatic means and interannual variations of daily precipitation characteristics in China, and high-resolution RCM simulations could produce improved precipitation amount and intensity.