欧亚积雪深度的时空分布特征分析

利用EOF分析、连续小波分析分别对欧亚大陆1979—2009年共30年秋冬季和春夏季积雪深度变化的时空分布特征进行了研究.结果表明:①对欧亚积雪深度进行EOF分析发现,1990年代前(后),秋冬季、春夏季欧亚大部分区域积雪深度呈现一致异常偏浅(深)的分布,且从高纬度到低纬度强度逐渐减弱;②积雪深度在1979―2009年表现出明显的年际和年代际变化特征,且具有显著的上升趋势;③小波分析发现欧亚秋冬、春夏季积雪深度均在20世纪80年代中期为准2 a的振荡周期,而在80年代后期到90年代初期为准5 a的振荡周期.不同的是整个90年代,春夏季积雪深度还存在准8 a的振荡周期.相比于秋冬季,春夏季欧亚积雪深度的时空分布更加复杂.

The characteristic analysis of temporal and spatial of snow depth over the Eurasian

The characteristics of temporal and spatial of snow depth over the Eurasian for 30 years (1979—2009) have been studied in the light of the Empirical Orthogonal Function (EOF) and Continuous Wavelet Analysis.It shows that firstly the EOF1 analysis of snow depth over the Eurasian in autumn and winter,spring and summer indicates that the snow depth has obvious decadal variation characteristics.It presented interdecadal change in the early 1990s with consistent rising trend (before (after) 1991,the snow depth is negative (positive) ).Secondly,versus to the autumn and winter,the spring and summer EOF1 of snow depth over the Eurasian has weaker even less positive anomaly and stronger even more negative anomaly.Thirdly,the Continuous Wavelet Analysis shows that there are obvious oscillation periods of quasi-2 years and quasi-5 years,respectively in the middle of 1980s and the late of 1980s,the early of 1990s.It is worth noting that there are obvious oscillation periods of quasi-8 years in the whole 1990s.Comparing to autumn and winter,the spring and summer have more complex distribution feature.