哈尔滨极寒天气特征和一次极寒天气成因分析

Characteristics of Extreme Cold Weather in Harbin and Analysis of the Cause of a Extreme Cold Weather

通过分析哈尔滨市1961-2023年日最低气温数据,筛选出日最低气温低于-40℃的极寒天气个例,总结哈尔滨市极寒天气征势。结果表明:(1)近63 a哈尔滨市极寒天气出现次数减少,且发生日数的年际变化显著;(2)极寒天气的时空分布特征:极寒天气主要出现在20世纪60-70年代,且时间分布均匀,21世纪初极寒天气出现一次激增,且集中出现在2001年;空间分布上极寒天气主要出现在哈尔滨市北部和东南部区域。本文以2023年哈尔滨市一次持续时间长、强度大、极端性强的极寒天气过程进行分析,得出极寒天气的成因包括:乌拉尔山高脊强烈发展导致极涡分裂南下,深厚强大的东北冷涡系统受东部阻塞高压的阻挡,长时间影响哈尔滨市造成强降温出现,且夜间风力小、辐射降温增强,共同影响造成极寒天气。

Based on the analysis of the temperature data from 1961 to 2023 of Harbin,we selected the extreme cold weather cases with daily minimum temperature below-40℃,and summarized the trend of extreme cold weather in Harbin.The results show that:(1)the occurrence of extreme cold weather in Harbin has decreased in recent 63 years,and the annual variation of the occurrence days is significant;At the beginning of the 21st century,there was a sharp increase of extreme cold weather,which was concentrated in 2001,and the extreme cold weather mainly occurred in the north and southeast of Harbin.This paper based on an extremely cold weather process in 2023 in Harbin with long duration,high intensity and strong extremes.It was concluded that the extremely cold weather was caused by the strong development of the High Ridge in Ural Mountains,which caused the polar vortex to split and move southward.The deep and strong northeast cold vortex system was blocked by the blocking high pressure in the east,and the long-term influence of the High Ridge in Harbin led to the strong cooling,at night,the wind force is small,the radiation cooling is strengthened,and the extreme cold weather appears.