欧亚大陆夏季地表温度的气候特征及与大气环流的联系

Climatic features of summer land surface temperature in Eurasian continent and its relationship with atmospheric circulation

采用1960-2010年NCEP/NCAR逐月再分析资料,利用经验正交函数（EOF）展开方法等,分析了欧亚大陆夏季地表温度变化特征及其与大气环流的关系.结果表明：欧亚大陆夏季地表温度的均方差在高纬度地区大于在低纬度地区.欧亚大陆夏季地表温度最主要的特征是全区一致变化,除了青藏高原东侧为降温趋势外,其他地区为变暖趋势,其中40～65°N增温明显;其次,高纬度地区表现出“-＋-”变化特征.西风环流指数的变化与地表温度的增温密切相关,而EU指数与中高纬度地区地表温度异常的分布类型密切相关.根据欧亚大陆夏季地表温度的气候特征和时空变化特征,确定了5个关键区.各关键区指数都有增温趋势,但是变化特征不同.不同关键区指数的异常所对应的环流形势异常均不相同,与不同关键区地表温度密切联系的环流因子也不相同.

Based on the NCEP/NCAR monthly reanalysis data from 1960 to 2010,this paper analyzed the variation characteristics of summer land surface temperature in Eurasian continent and its relationship with atmospheric circulation by using the empirical orthogonal function（EOF） method.Resuits show that mean square deviation of Eurasian summer land surface temperature in high latitudes is greater than that in low latitudes.The main feature of summer land surface temperature in Eurasian continent is the consistent variation pattern in the whole region.Except for cooling trend on the east side of Tibetan Plateau,warming trend exists in other areas of Eurasian continent,especially in 40-65°N.Secondly,summer land surface temperature shows ＂-＋-＂ anomalous pattern in high latitudes.Westerly circulation index closely relates to the warming temperature,while the EU index closely relates to the anomalous pattem of summer land surface temperature in middle and high latitudes.Based on the climate features and spatial-temporal features of summer land surface temperature in Eurasian continent,five key areas have been identified.The indices in the five key areas have warming trend,but their change features are different.The different abnormal circulation patterns correspond to the different indices in the five key areas,and the circulation factors which closely relate to land surface temperature in the five key areas are different.