Convection-permitting regional climate simulations over coastal regions in China

Abstract

This study investigates the regional characteristics and land/sea differences in precipitation and wind along the coast of China, utilizing the Weather Research and Forecasting (WRF) model for a continuous 10-year (2009-2018) simulation at 4km resolution. The results indicate that the WRF model, operating at convection-permitting resolution, can accurately simulate annual precipitation and the rainfall frequency, but it tends to underestimates precipitation over the ocean while overestimates frequency of drizzle rain. The study also reveals that, along the Chinese coastal region, the sub-daily scale precipitation events are most frequent in EC, and WRF tends to underestimate the frequency of events lasting longer than 3 hours. WRF simulates relatively consistent land-sea maximum precipitation between land and sea areas, with smallest deviation, below 20% observed in maximum hourly precipitation over the sea. Furthermore, observations show that the diurnal cycle of precipitation peaks at 16:00-17:00 local time over land, with most afternoon precipitation lasts approximately 1 to 6 hours. The WRF model successfully captures the observed diurnal variation of precipitation over land and sea in different regions. However, the WRF simulation indicates a shorter duration of afternoon precipitation, lasting less than 5 hours and an earlier peak. In addition, WRF adequately reproduces the annual and seasonal mean windspeeds for each region, with a slight overestimation during summer. WRF also reasonably captures the frequency distribution of windspeed and wind direction and can identify the occurrence frequency of land-sea breeze in each sub-region. Overall, the study offers valuable insights into the regional characteristics of precipitation and wind along the coast of China and highlights the WRF model’s effectiveness in accurately simulating these phenomena.