我国冷空气活动的特征及其与欧亚大陆积雪的关系

本文用1951—1989年38个冬半年的冷空气活动的资料，分为寒潮、强冷空气、弱冷空气三级，并按候、月、年研究其统计特征。结果指出:1.寒潮逐月累计频数表明，以11月和3月最多，2月最少。2.寒潮和强冷空气总和的强过程的年频数存在很大的年际变化，不但有2~5年变动，而且有约20年的气候变动。自1970年以后，强过程总的趋势是逐渐减少的。另外，本文还初步探索了冬季欧亚大陆积雪与侵入我国冷空气的关系，冷空气是经过数据化处理的。得到的初步结果是，两者同期关系很差，而冬季积雪与春季冷空气有很好的正相关。

Statistical Features of the Cold Waves Invaded China and Their Relation to the Snow Cover Area over the Eurasian Continent

Using the record of cold waves invaded China during the 38 winter half-years from September 1951 through April 1989, statistical features of the cold waves are pantadly, monthly and yearly investigated. The cold waves are divided into three grades, i.e. , severe, strong and moderate. The statistical results are as follows: 1. From the accumulated monthly frequencies it is shown that severe cold waves occur most in November and March, but least in February. 2. Yearly frequences of the strong events of the severe cold waves together with the strong cold waves show obvious interannual variations, in which there are not only 2－5 year oscillations, but also about 20 yearly climatic variations. And, in the last twenty years the strong events tend to gradually decrease. In addition, the relationship between the cold waves invaded China and the winter snow area coved over the Eurasion continent has been preliminarily studied based on digitalizing the cold wave record.