Characteristics of Extreme Cold Weather in Harbin and Analysis of the Cause of a Extreme Cold Weather
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 cen-tury,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 ex-tremely 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 ap-pears.
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