川渝地区主汛期降水的年代际变化与短期气候预测模型的建立

Interdecadal Variations of Summer Precipitation and a Short-Term Climate Prediction Model in Flood Period of Sichuan and Chongqing

利用1951—2007年川渝地区20个代表站主汛期的降雨量资料、太平洋逐月海温资料和NCAR/NCEP逐月再分析资料,通过EOF等方法,研究了川渝地区主汛期降水的年代际变化,并建立了短期气候预测模型。结果表明,川渝地区主汛期降水主要模态存在明显的年代际变化,不同时段降水异常最主要的模态存在差异,从20世纪90年代初开始,全盆地降水异常一致型是最主要的模态。用前期赤道中东太平洋的海表温度、北大西洋地区的西风强度、西北太平洋极涡强度和东亚大槽强度作为预测因子,建立的降水预测模型对近年川渝地区汛期降水有较强的预测能力。降水主要模态的年代际变化及其所对应的前期预测因子的变化是影响模型预测能力的关键因素。

Using the observed monthly precipitation and Sea Surface Temperature（SST） and NCEP/NCAR reanalysis value data,the interdecadal variations of summer precipitation in the flood period of Sichuan and Chongqing was investigated,and a short-term climate prediction model was built.The results indicate that the principal modes of summer precipitation are different during the different periods.The homogenous of precipitation anomalies is the most important mode since early 1990s.A short-term climate prediction model was built by using the prediction factors： SST in equator center-east Pacific,magnitude of zonal wind in North Atlantic,intensity of Polar Vortex in Northwest Pacific and intensity of East-Asian trough.The performance of the model is better based on the test from 2002 to 2007.The interdecadal variations of principal modes of summer precipitation and its predicting factors contribute to the variation of the model prediction abilities.