Convection-permitting regional climate simulation of warm-season precipitation over Eastern China

Yuxing Yun,Fei Chen,Roy Rasmmusen,Xudong Liang,Changhai Liu,Ling Huang,Yali Luo

doi:10.1007/s00382-019-05070-y

Abstract

Convection-permitting regional climate models have been shown to improve precipitation simulation in many aspects, such as the diurnal cycle, precipitation frequency, intensity and extremes in many studies over several geographical regions of the world, but their skill in reproducing the warm-season precipitation characteristics over the East Asia has not been robustly tested yet. Motivated by recent advances in computing power, model physics and high-resolution reanalysis, we use the convection-permitting weather research and forecasting (WRF) model configured with 3 km grid spacing to simulate the warm-season precipitation in eastern China for 10 seasons (2008–2017). The hourly 31-km-resolution ERA5 reanalysis data are used to provide initial and boundary conditions for the simulations. The objectives are (1) to evaluate the model skill in simulating warm-season precipitation climatology in the East Asian monsoon region, (2) to identify the promises and problems of the convection-permitting simulation, and (3) to investigate solutions for the model deficiencies. Results demonstrate that the 3-km-resolution WRF model reasonably reproduces the spatial characteristics of seasonal and sub-seasonal precipitation, the seasonal meridional migration associated with the summer monsoon activity, the diurnal variation phase and amplitude, and the propagating convection east of the Tibetan Plateau. The major deficiency is that the model overestimates precipitation amount, especially in the afternoon. Analysis and sensitivity experiments suggest that improved treatment of sub-grid cloud fraction and the aerosol effects may help to suppress the oft-reported high precipitation bias. These results provide useful guidance for improving the model skill at simulating warm-season precipitation in East Asia.

Highlights

China lies on the east part of the Asian continent, west coast of the Pacific
2 National Center for Atmospheric Research, Boulder, USA 3 Guangzhou Institute of Tropical and Marine Meteorology, Guangzhou, China 4 Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing, China west side of the country is the highest with the Tibetan Plateau (TP), and the topography decreases in cascades towards the east
The major model deficiency is the high bias in simulated precipitation in most regions, similar to what Li et al (2018) and Zhu et al (2018) showed in their high resolution simulations

Summary

Introduction

China lies on the east part of the Asian continent, west coast of the Pacific. Moisture in the atmosphere is mainly supplied by the moist and warm southwesterly monsoon flow. The. Guangzhou, China 4 Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing, China west side of the country is the highest with the Tibetan Plateau (TP), and the topography decreases in cascades towards the east. China 4 Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing, China west side of the country is the highest with the Tibetan Plateau (TP), and the topography decreases in cascades towards the east This specific geographical position and topographical distribution determines the general precipitation climatology in China, while the detailed features of precipitation are results of complex interactions of multiple processes. During the warm season (May–September), the East Asian summer monsoon dictates the sequential formation of three major rainy seasons in China: the early summer rainy season in southern China (May to mid-June), the Mei-yu season over the Yangtze and Huai River basins (mid-June to midJuly), and the late summer rainy season in northern China (late July and August) (Ding 2013)

Results

Discussion

Conclusion