太平洋海温与嘉兴夏季降水年代际变化关系

Sea Surface Temperature Anomalies over the Pacific and Its Interdecadal Correlations with Summer Precipitation in Jiaxing

用1953-2003年的51a嘉兴地区降水资料及同期NCAR的5°×5°海温(10°S～50°N,120°E～80°W)再分析资料作相关,结果得出太平洋海温与嘉兴夏季降水在20世纪70年代末发生了一次同期的年代际跃变。不同海区的海温异常对嘉兴夏季降水都有一定影响。在年代际尺度上,降水与西太平洋暖池区、赤道东太平洋的海温有明显的正相关,与西风漂流区及其以南的中太平洋海温则呈现反相关。在丰水期与枯水期,西风漂流区的海温春夏秋冬无论哪个季节都存在与降水反向的显著距平,该区海温是影响嘉兴夏季降水的一个强信号。而降水多寡不同时段,西太平洋暖池的海温在前冬和当年春季有较明显的距平,其他季节则无显著变化,降水变化滞后1～2个季度。赤道中东太平洋则在春夏季会有一个较大幅度的海温距平,夏季降水与之呈现同期或滞后一个季度相关。可见作该地区长期预报时,不同时段应着重关注不同海区的海温状况。

In this paper,Studies show that interdecadal variations of summer precipitation in Jixing and sea surface temperature over the Pacific happened simultaneously at the end of 1970s.In view of the interdecadal time scale, the summer precipitation has obviously positive correlations with SST in west Pacific warm pool and equatorial eastern Pacific,while has negative correlations with SST in west wind drift and the area south to it.As the SST in west wind drift which have remarkably positive or negative anomalies opposite to the precipitation ones regardless of plentiful or low precipitation years all year round,is a strong signal to summer precipitation of Jiaxing. The SST in west Pacific warm pool in spring and previous winter has obvious 1-to-2-season leading correlations with the precipitation in summer,while the precipitation in summer has a simultaneous and one-season lagging correlations with the SST in equatorial central and eastern Pacific.