冬半年欧亚雪盖变化对东亚环流的影响

对１９７３～１９９４年期间欧亚雪盖和东亚５００ｈＰａ高度距平资料进行旋转扩展主成分分析，研究了冬半年欧亚雪盖异常与后期夏半年东亚环流分布连续演变的关系及其可能机制。结果表明前期秋冬春季欧洲、中亚和东亚中高纬雪盖异常不同的动态变化激发出具有不同持续性的东亚低频流型，而夏半年东亚副热带环流纬向扩展型演变与前期冬半年欧亚雪盖异常无关。

THE INFLUENCE OF THE VARIATIONS OF SNOW COVER IN EURASIA FOR HALF YEARS WINTER ON THE CIRCULATIONS OVER THE EAST ASIA

The relationships between the snow cover anomalies for half years winter and the distributions of circulation for the following half years summer on continuous evolutions have been investigated by using the rotated extended principal component analysis based on the data of the snow cover in Eurasia and the 500 hPa height anomalies field over East Asia for the period 1973 through 1994,and the possible mechanisms are discussed.The results indicate that the low frequence flow patterns with different persistence have been excited by the different dynamic evolutions of the snow cover anomalies in Europe,in Medium Asia,at middle high latitude in East Asia from the preceding fall,winter to spring. No relationship betwwen the evolutions of the zonal elongated pattern is found for circulation over subtropical East Asia from spring to fall and the Eurasian snow cover anomelies for the preceding half years winter.