Abstract:

Based on the daily precipitation and temperature data of eleven meteorological stations in Daxing'anling forest region in Inner Mongolia Autonomous Region from 1970 to 2019, the spatial and temporal variation characteristics of snowfall in this region were analyzed using trend analysis method, anomaly method, M-K mutation method and sliding t-test method after extracting the snowfall data.The results show that the total snowfall and all grades of snowfall indicate an increasing trend in the Daxing 'anling forest region, and the increasing trends of light snow and heavy snow were small.The amounts of light and moderate snow reach the maximum in the 2000s, and the amounts of heavy snow and snowstorm reach the maximum in the 2010s.The contribution rate of snowfall in each grade to the total precipitation is as follows: light snow>moderate snow>heavy snow>snowstorm.The monthly variation of snowfall in all grades shows an "M" shape, and the peak value of total snowfall occurs in November.In terms of mutation, the total snowfall has a significant mutation in 1995, while the snowfall of light snow, moderate snow, heavy snow, and heavy snow has no significant mutation.In space, the total snowfall and the snowfall of each grade (except snowstorms) generally show a trend, with more in the north and less in the south, more in the west, and less in the east.In the forest area, the beginning day of snowfall is delayed, and the end day is advanced.The length of the snow season is shortened by 2.3 days every 10 years.

Key words: Different grades of snowfall, Snow contribution rate, M-K mutation method