西南地区冬季气温时空特征分析

Analysis of Spatial-Temporal Features of Winter Temperature in Southwestern China

利用西南地区五省市区83个测站1961-2008年历年12月至次年2月月气温资料,采用EOF和REOF方法对冬季气温的空间异常特征、时间变化规律以及冬季气温对ENSO循环的响应进行了诊断分析研究.结果表明:西南地区冬季气温的主要异常模态表现为一致偏冷或偏暖型、东西反向型.西南地区冬季气温的异常敏感区域为盆地丘陵区、高原区、藏南区和高原东北区.20世纪60年代以来,西南地区冬季气温呈一致上升趋势,高原地区增温显著,盆地丘陵地区增温缓慢.西南地区冬季气温异常对ENSO循环不同位相的响应有一定的差别,El nino年,西南地区冬季气温东部偏高,高原地区偏低,东西响应呈反位相.La nina年,西南地区冬季气温以偏冷为主.

The data of winter temperature at 83 observational stations from 1961 to 2008 in Southwestern China are used to diagnose and analyze its spatial anomaly features,time evolution patterns and response to ENSO（El Nino-southern oscillation circulation） with EOF（empirical orthogonal function） and REOF（rotated empirical orthogonal function） methods.The results indicate that the main anomaly structures of winter temperature in Southwestern China present a cold or warm type in all the areas,and its spatial changes exhibit an opposite pattern from the west to the east.The anomaly sensitive areas are the plateau region,the hilly regions of the Sichuan Basin,Southern Tibet and the northeast of the plateau.The winter temperature in Southwestern China from 1960 to 2009 shows a rising trend,the increase being remarkable in the plateau region and slow in the hilly regions of the basin.There are differences in the response of winter temperature in Southwestern China to ENSO circulation in different phases.With El Nino phenomenon,the east of Southwestern China is relatively warm in winter and relatively cool on the plateau,an opposite phase from west to east.With La Nina phenomenon,the winter temperature throughout Southwestern China is comparatively cold.