Evaluation of Precipitation Simulation in East Asian Monsoon Areas by Coupled Ocean-Atmosphere General Circulation Models
全球海气耦合模式对东亚季风降水模拟的检验

Based on the monthly precipitation data of Climate Prediction Center Merged Analysis of Precipitation(CMAP) and European Center for Medium range Weather Forecasting(ECMWF) 40-year reanalysis data(ERA40),the abilities of 17 Coupled Ocean-Atmosphere General Circulation Models(CGCMs) from Intergovernmental Panel on Climate Change(IPCC) Fourth Assessment Report(AR4) to simulate precipitation and circulation in East Asian summer monsoon regions are evaluated.The results show that(1) most of the models can reproduce the basic precipitation pattern that precipitation decreases from the ocean in the southeastern part of East Asia to the inland of China in the northwestern part of East Asia;(2) most of the models also can generally capture the advance of rain belt in eastern China.However,there are still considerable differences,which are(1) the climatic mean values and variability of rainfall in most models are much less than observation;(2) there is bias in the simulation of advance and retreat of rain belt,especially over the ocean,and some models even cannot capture the basic seasonal progress over the eastern ocean.Therefore,the current CGCMs have limited capability to simulate precipitation in East Asian monsoon areas,and need to be further improved.The multi-model ensemble shows that the simulated circulation intensity in summer is weaker than observation,which may restrain the development of deep convection and be unfavorable for the occurrence of precipitation,especially in the eastern part of China.Furthermore,low moisture content and related weak moisture transport may be one reason that results in the underestimate of summer precipitation in East Asian monsoon areas in the models.