关键词: 高原春夏季温度, 太平洋海温, 高度场

Abstract:

The clustering analysismethod is used to divide the temperature field in sp ring and summer over the Qinghai - Xizang Plateau into three areas for p redicting the temperature trends of different areas. Based on the correlation between the temperature indexes in sp ring and summer over the Plateau and the Pacific SST in the p receding season, the SST distribution index is defined. When the winter SST over the western Pacific is higher ( lower) than normal, the sp ring temperature in Areas II of the Plateau is higher ( lower) ; while the winter SST in the western and eastern Pacific is higher ( lower) than normal, the summer temperature over southern Areas II and Areas III of the Plateau is higher ( lower) . Further analysis are conducted about the correlation between these two SST distributions and the 500 hPa geopotential height field in sp ring and summer in the Northern Hemisphere. The results show thatwhen the winterwestern Pacific SST index is higher ( lower) , the cold air activities over high latitude weaken ( strengthen) and itsmoving route northward ( southward) ; meanwhile, the geopotential height field is lower ( higher) , it is advantageous ( disadvantageous) to the southern air currentmoving northward and the circulation conversion from the winter type to the summer one, and the sp ring temperature over the central Plateau is higher ( lower) than normal. In contrast, when the integrated index ofwinter SST in the western and eastern Pacific is higher ( lower) , the northern Plateau to southern central - Siberia ridge and the western Pacific subtrop ical high in summer strengthen (weaken) , and the Plateau controlled by high system, the summer temperature over the central and southern Plateau is higher ( lower) .

Key words: sp ring and summer temperature over the Plateau, Pacific SST, geopotential height field