【摘要】 从预测高原不同区域春、夏季温度趋势分布的需要出发,利用聚类分析法将高原温度场分为3个区域。通过对3个区春、夏季温度指数与前期太平洋海温相关普查,定义了与高原春、夏季温度指数相关关系清晰的海温分布型指数。冬季西太平洋海温偏高(偏低)的海温分布型造成后期高原II区春季温度偏高(偏低);冬季西太平洋海温、东太平洋海温同时偏高(偏低)的海温分布型造成后期高原II区南部、III区夏季温度偏高(偏低)。进一步分析这2种海温分布型与后期春夏季500 hPa北半球高度场的相关关系,结果表明:当冬季西太平洋海温指数偏高(低)时,春季高度场高纬冷空气活动的势力弱(强)且路径偏北(南),同时高原高度场较低(高),有利于(不利于)偏南气流北上,有利于(不利于)冬季向夏季环流形势的转变,春季高原中部温度偏高(偏低);而当冬季西太平洋、东太平洋海域海温综合指数偏高(低)时,同年夏季500 hPa高度场高原北部至中西伯利亚南部脊加强(减弱),高原及北部为高值(低值)系统活动,西太平洋副高偏强(弱),夏季高原中部、南部温度偏高(偏低)。更多还原

【Abstract】 The clustering analysis method is used to divide the temperature field in spring and summer over the Qinghai-Xizang Plateau into three areas for predicting the temperature trends of different areas.Based on the correlation between the temperature indexes in spring and summer over the Plateau and the Pacific SST in the preceding season,the SST distribution index is defined.When the winter SST over the western Pacific is higher(lower) than normal,the spring 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 spring and summer in the Northern Hemisphere.The results show that when the winter western Pacific SST index is higher(lower),the cold air activities over high latitude weaken(strengthen) and its moving route northward(southward);meanwhile,the geopotential height field is lower(higher),it is advantageous(disadvantageous) to the southern air current moving northward and the circulation conversion from the winter type to the summer one,and the spring temperature over the central Plateau is higher(lower) than normal.In contrast,when the integrated index of winter SST in the western and eastern Pacific is higher(lower),the northern Plateau to southern central-Siberia ridge and the western Pacific subtropical high in summer strengthen(weaken),and the Plateau controlled by high system,the summer temperature over the central and southern Plateau is higher(lower).更多还原