冬季积雪的异常分布型及其与冬、夏大气环流的耦合关系

Patterns of winter snow depth anomaly with their coupled relation to atmospheric circulation in summer and winter

摘要:

采用ECMWF1979～1993年2.5°×2.5°的网格点积雪深度资料,研究了较为细致的积雪异常的空间分布特征,揭示了欧亚大陆冬季积雪的异常空间分布型;并采用SVD方法研究了冬季积雪的异常分布型与冬、夏大气环流的耦合关系。结果表明:欧亚大陆冬季积雪深度存在典型的异常空间分布型;积雪的异常分布型与冬、夏大气环流之间均存在一定的耦合关系。冬季积雪的异常分布型与大气EU遥相关型存在明显的同时性相互作用,大气EU遥相关型有利于冬季积雪异常分布型的出现和维持,而积雪异常分布型对大气EU遥相关型的发生起一定的作用,进而对冬季风活动产生影响。冬季积雪的这种异常分布型与夏季大气环流,尤其是东亚地区的夏季大气环流,也存在一定的联系。积雪异常分布型可以通过影响副热带高压的南北进退,对东亚季风及中国夏季雨带产生影响。

Abstract:

WT5BZ]With the snow depth data of ECMWF,the detailed spatial patterns of winter snow anomaly are studied,and the typical anomalous snow patterns are found,the coupling relationships between snow anomaly pattern and winter/summer atmospheric general circulation are discussed with singular value decomposition(SVD)analysis method as well.Results show:(1)winter snow depth anomaly shows its typical spatial patterns;(2)snow anomaly pattern bears coupling relationships to both winter and summer atmospheric general circulations.The anomalous pattern of winter snow depth interacts strongly with atmospheric EU teleconnection pattern.On one hand,the atmospheric EU teleconnection pattern favors to the appearance and maintenance of snow anomaly pattern;on the other hand,the anomalous pattern of snow depth has important impacts on winter atmospheric EU pattern and East Asian winter monsoon.There is also a linkage between snow anomaly pattern and summer atmosphere.Snow anomaly pattern can influence N/S position of western Pacific subtropical high,summer monsoon and summer rainbelt in China.