Bias Analysis Of RegCM4 Simulated Future Climate Change Of China

This study adopts RegCM-4.4-rc8 released on May 7,2013, and simulated Chinese climate of recent years. Compare simulated and observed data, and calculate their difference with series of mathematic methods as the simulation deviation of RegCM4. Then simulate the Chinese climate in future decades, obtain a more accurate forecast with the RegCM4 simulation deviation to discuss the climate change trend in China. The major work and conclusions are follows:1. By testing the simulation results from different lateral boundary schemes, cumulus convection parameterization schemes and land surface schemes of RegCM4 in China, and choose a better physical parameterization scheme for the following long-term climate simulation. After a series of comprehensive comparison, it showed that the relaxation scheme, Emanuel scheme and Biosphere Atmosphere Transfer Scheme have a better performance in RegCM4.2. Simulate the climate during Dec.1950-Dec.1980, Dec.1960-Dec.1990 and Dec.1970-Dec.2000, compare the simulated temperature and precipitation with CRU observation, and calculate their differences. The mean deviation values in the 3 periods are considered to be the simulation bias of RegCM4.3 Simulate the future climate of China from 2030 to 2060, then add the simulation bias to the simulation to improve the simulation accuracy of RegCM4 over China, and analyze the trend of climate change based on the results. The study show that:the land temperature in China will keep a rising trend, and the annual temperature over most part of China will rise by about 1-2℃. The precipitation doesn’t have an obvious trend, with the same spatial distribution as current, the precipitation decrease from south-east to north-wes However, the precipitation decreases by 0-0.5 mm/day in the south, increase by 0-0.5mm/day in the north.