夏半年青藏高原东部大气热源异常对环流和降水的影响

THE IMPACT OF THE ANOMALOUS HEAT SOURCES OVER THE EASTERN TIBETAN PLATEAU ON THE CIRCULATION OVER EAST ASIA IN SUMMER HALF YEAR

本文利用高原23个测站探空资料，经客观分析求得的1983－1992年夏半年（5－10月）逐月青藏高原东部大气热源和水汽汇积分值，讨论了高原东部大气热源对北半球大气环流以及对我国降水的影响。月距平资料显示，高原东部大气热源在ENSO年一般有所加强，与此相应，500hPa高度场从高原到淮河流域为一低值区，蒙古一带为高压区，100hPa高度场高原上空为高压区，我国东北，朝鲜和日本一带为低值区。本文还用合成分析方法揭示了热源异常对东亚地区环流系统的影响。结果表明，高原东部热源异常增大时，低层西南季风和高层青藏高压加强。热源时间系列还与我国降水有较好关系。当高原热源加强时，长江上游和淮河流域降水增加，而我国东南地区降水减少。高原热源加强还预示淮河流域未来1－2个月的降水增加。

The impact of the anomalous heat sources over the eastern Tibetan Plateau on the circulation over East Asia and precipitation in China are studied during the period from May to october of 1983-1992. The composite method is used to see the relationship between the anomaloUs heat sources and the circulation in East Asia. When anomalous heat source is positive, the cross-equatorial low-level jet near Somali and 105°E are stronger than normal. The anomalous precipitation amounts are positive over the region of Huai River and Sichuan Basin, on the other hand, along the coast region of Southeastern China, we see the negative precipitation anomalies.The correlation maps of geopotential heights at 500hPa and 100hPa with respect to heatsource over Eastern Tibetan Plateau show the predominance of ultra-long wave with zonal wavenumber 1 or 2. We may infer from this teleconnection structure that the Stationary disturbance with zonal wavenumber 1 and 2 changes interannually, due to the changes in intensity of the heat sources over the Tibetan Plateau, but without too much changes in the heat source location.