欧亚北部冬季增雪“影响”我国夏季气候异常的机理研究:欧洲冬季增雪的重要作用

Mechanism for the Correlation of Winter Fresh Snow Extent over Northern Eurasia and Summer Climate Anomalies in China: The Important Role of Eurasian Winter Fresh Snow Extent

在作者前期研究(穆松宁和周广庆,2012)的基础之上,本文主要利用了EOF分析和相关分析,对欧亚北部冬季新增雪盖面积(Total Fresh Snow Extent,记为TFSE)与我国夏季气候异常之间"隔季相关"的机理进行了更进一步的探讨,主要目的在于寻找TFSE气候效应的冬季增雪面积关键区。结果表明,虽然欧洲中纬冬季增雪面积(文中均以TFSE-1表示)与我国夏季气候异常的关系不很显著,但其变化维系了上述"隔季相关"的物理途径,其变化对TFSE的气候效应而言起关键作用,但是,亚洲中纬冬季增雪面积(文中均以TFSE-2表示)的贡献尚不清楚;另外,对TFSE的气候效应而言,起作用的实际上是欧亚中纬冬季增雪面积(文中均以TFSE-1-2表示),其不但与我国夏季气候异常具有更显著的"隔季相关",而且这种"隔季相关"还具有和TFSE非常相似的、但更为清晰的物理途径,因此,在气候预测的意义上,TFSE-1-2可替代TFSE。

Based on previous studies （Mu and Zhou, 2012）, the linkage mechanism between winter northern Eurasian total fresh snow extent （TFsE） and subsequent summer climate anomalies in China is investigated in depth using empirical orthogonal function （EOF） and correlation analysis, with the primary purpose of finding the key region of fresh snow extent over northem Eurasia. The results show that the correlation between mid-latitude fresh snow extent in Europe （TFSE-1） and subsequent summer climate anomalies in China is unremarkable. However, TFSE-1 variability supports the physical mechanism for TFSE summer climate correlation. Thus, TFSE-1 provides a crucial influence on the climatic effects of TFSE. The role of mid-latitude fresh snow extent in Asia （TFSE-2） is unknown. However, winter fresh snow extent in Eurasian middle-latitude regions （TFSE-1-2）, which significantly affects the summer climate in China, dominates climatic effects of TFSE because the correlation between TFSE-1-2 and the summer climate in China has a clearer physical mechanism than the correlation between TFSE and the summer climate, which suggests that TFSE-1-2 could replace TFSE in climate forecasts.