Summer Prediction of Moisture Transport in the Middle and Lower Reaches of the Yangtze River in BCC_CSM Mode
Based on hindcast datasets of the Beijing Climate Centre climate system model and NCEP reanalysis datasets,using correlation analysis,composite analysis and others,firstly,the summer atmospheric moisture content and the characteristics of moisture transport in the middle and lower reaches of the Yangtze River are analyzed,and the relationship between rainfall and the summer monsoon are discussed.Secondly,the pattem of moisture transport simulation capabilities are evaluated,and possible reasons for the model error are analyzed.Results shows that:(1) summer precipitation in the Yangtze River has a close relationship with the East Asian summer monsoon,and the East Asian summer monsoon affects mainly through the moisture transport in Yangtze River to influence precipitation,moisture transport is therefore an important hub contact between precipitation and water origin;(2) there is a cyclonic bias of atmospheric water vapor transportation in low latitude of Yangtze River,which led to atmospheric moisture content of the Yangtze River decrease,this is an important reason for the precipitation simulation of below normal level in this region,negative biases simulation centers distributed between 20°N-40°N,while low latitudes is a positive deviation distribution.Further studies shows that the simulation of the deviation of the Yangtze River moisture transport mainly caused by an analog deviation the summer monsoon,and the simulation of the weak monsoon is better than the simulation of strong monsoon.