长江中下游夏季雨带分型及其年代际变化Ⅱ：数值模拟

在对长江中下游夏季降水进行分型的基础上,分析了长江流域南北两支雨带与春季太平洋海温的相关关系,并采用NCAR/CAM 3.0大气环流模式对前期海温进行了敏感性试验,结果表明：赤道东太平洋区域（150～90°W,5°S～5°N）的海温异常对两支雨带夏季降水有重要影响,海温正异常时南支雨带旱、北支雨带不明显,海温负异常时南支雨带涝、北支雨带旱;前期赤道东太平洋海温强迫可以在北半球对流层激发出遥相关波列,并影响长江流域南北两支雨带的旱涝分布,前期赤道东太平洋海温对南支雨带的影响比北支雨带大。

Summer Rain Band Pattern in Mid-Lower Reaches of Yangtze River and Its Interdecadal Variability Ⅱ:Numerical Simulations

The relation between summer south and north branch rainbands over the Changjiang River basin and spring Pacific sea surface temperature（SST） is numerically investigated using the NCAR/CAM 3.0 global atmospheric circulation model. The results show that spring （MAM） SST anomaly in the eastern equatorial Pacific（EEP;5°S-5°N, 150-90°W） has important impact on summer（JJA） precipitation over the two branch rainbands：when spring SST anomaly in the EEP is positive, summer rainfall of south branch rainband is deficit, and that of north branch raindand is not obvious affected; and when the spring SST anomaly is negative, summer rainfall of south branch rainband is excessive, and that of north branch rainband is deficit. Anomalous spring SST forcing can trigger teleconnection wavetrains in the troposphere of Northern Hemisphere, which affect summer precipitation of both south and north branch rainbands in the Changjiang River basin,but with more obvious influence on the precipitation of the former.