欧亚冬季雪盖异常及其与ENSO循环的关系
投稿时间:2001-12-13  修订日期:2002-04-26  点此下载全文
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作者单位
王静 南京气象学院, 大气科学系, 江苏, 南京, 210044 
孙照渤 南京气象学院, 大气科学系, 江苏, 南京, 210044 
基金项目:国家重点基础研究发展规划项目(G1998040901-3)
中文摘要:利用NOAA-NESDIS提供的1973-2000年北半球雪盖面积资料,研究了欧亚冬季雪盖的时空特征,发现欧亚大陆中高纬地区积雪有明显的整体性分布特征,而50°N以南的冬季积雪随纬度的变率较大;欧亚大陆中高纬地区冬季积雪呈东西反位相分布。利用小波分析发现,冬季欧亚积雪具有显著的3-4a周期。最后指出,欧亚积雪异常引起的下垫面热力异常可能为次年ElNino事件的爆发提供触发条件。
中文关键词:欧亚雪盖异常  特征向量  小波分析
 
Characteristics of Winter Snow Cover Anomalies over Eurasia and Its Relations to ENSO Cycles
Abstract:Based on the weekly snow cover data in the Northern Hemisphere from Jan.1,1973 to Dec.31,2000 provided by NOAA-NESDIS,the spatial/temporal characteristics of winter snow cover anomaly over Eurasia are studied.It is found that the perpetual snow of mid-high latitudes in Eurasia has obvious whole-distributing feature,while the winter perpetual snow south of 50°N varies with latitudes;the first EOF eigenvector of the inter-annual departure field of winter snow area over Eurasia indicates that the winter perpetual snow of mid-high latitudes exhibits an east-west opposite-phase distribution.Using wavelet analysis,time coefficients of the first and second spatial patterns of EOF analysis are analyzed,and it is found that the 3~4-year fluctuation period is the largest component in the temporal variation of Eurasian winter perpetual snow.Analysis indicates that the thermal anomaly of underlying surface brought about by Eurasian perpetual snow anomalies may possibly offer a triggering mechanism for the outbreak of El Nino in the next year.
keywords:Eurasian snow-cover anomaly  eigenvector  wavelet analysis
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