利用IPCCAR4中8个气候系统模式的环流、对流和降水资料,结合实际的观测及再分析资料,从年际尺度上比较分析了这些气候系统模式对夏季西太平洋副热带高压南北位置、暖池对流和江淮降水关系的模拟能力,结果表明在西太平洋副热带高压随纬度分布的模拟中,经向分辨率高的模式存在一定的优势。在夏季西太平洋副热带高压的南北位置、暖池对流和江淮降水关系的模拟上,GFDL-CM2.1能合理地表征三者之间的关系;在影响东亚夏季风年际变化的东亚太平洋遥相关型的模拟上,GFDL-CM2.1和ECHAM5_MPI/OM能够较好地模拟出其特征,其中前者模拟结果要明显好于后者。同时利用GFDL-CM2.1在SRES A1B情景下的试验结果,EAP(East Asia/Pacific)指数与中国东部降水的变化关系得出,随着大气中二氧化碳浓度增加,在21世纪前期,江淮偏旱的概率较高;21世纪后期,江淮降水可能偏多。
Interannual variability is a prominent character of East Asia summer monsoon, and to what extent state-of-the-art climate system models can simulate its characters draws the attention of researchers of East Asia Monsoon. The relationships among meridional location of West Pacific Subtropical High( WPSH), convection above warmpool and precipitation in the Yangtze and Huaihe River Valley in summer in interannual scale are investigated by using the eight IPCC AR4 simulations in 20 century, observations and reanalysis data. It is revealed that, of the eight climate system models, GFDL-CM2.1 can realistically represent the relationships, and GFDL-CM2.1 and ECHAM5_MPI/OM can significantly simulate East Asia/Pacific(EAP) teleconnection while the result of GFDL-CM2.1 shows nearly the same as that of reanalysis. It is also found that, in order to well simulate the merdional location of EAP teleconnection, it is a prerequisite that the model can well reflect the climatoligical merdional location of WPSH. When come to the simulation of the continual distribution of WPSH merdional location, models with higher merdional resolution tend to have better results. By analyzing the experiment results of GFDL-CM2.1 in scenario SRES AI B,it is found that, as the CO2 concentration in atmosphere increases,during first several decades in 21 st century, summer precipitation in the Yangtze and Huaihe River Valley tends to be below normal;while during last few decades in 21st century, the rainfall may be above average.