威海市冬季暴雪的天气气候特征

THE WEATHER AND CLIMATE CHARACTERISTICS OF HEAVY SNOW IN WEIHAI IN WINTER

对 198 0～ 1999年冬季 (11月至次年 2月 )威海市降雪量和 0 8时探空及地面资料统计分析 ,结果表明威海市2 0年中冬季共出现 2 1个暴雪日 ,平均每年有 1个暴雪日 ,造成威海市冬季暴雪的天气系统为冷涡深槽和南支槽两大类 ,其中主要影响系统为冷涡深槽类 ,发生 2

Using the data of precipitation in Weihai in winter from 1980 to 1999(Nov.-Feb.), the statistical characteristics of heavy snows are obtained. In these years, there were 21 heavy snows,average 1.0 heavy snows a year. The area of heavy snows is generally smaller, and the possibility of heavy snows over two meteorological observing stations or more is only 0.29. The uneven distribution of heavy snows is in association with the meteorological observing station's location. Most of heavy snows occurred in Wengdeng (average 0.7 heavy snow a year) while the least in Rushan(only one time in these years). The weather systems which caused heavy snows can be divided into two patterns: northeast cold vortex or trough line, and south trough line. The probability of the cold vortex accounts for 95.2%. It is predominant and the vortex caused 20 heavy snows in these years.