A Case Study of Snowstorm Associated with Jianghuai Cycle on Atmospheric Influence Factors and Character of Snow Cover

Abstract: This study investigates the character and complicated atmospheric influence factors of snow cover on a snowstorm event associated with Jianghuai cycle occurred from 21 to 22 February 2017 by automatic station, intensive and routine observation data. The results are as follows: (1) Special structure leads to different distribution  of snowfall and snow cover from south to north in Shandong province.(2) Snow depth rises to maximum when snow ends with timeliness. The maximum is not sure to continue at 8'clock next day.(3) Snow depth is influenced by precipitation type, snowfall, Snowfall intensity, air temperature, ground temperature and wind speed. Sleet can produce snow cover with 1cm before it converts to snow, or quantitative snow cover won't form. Snow-to-liquid ratio has great difference in various stations, and the average with 0.5cm·mm-1 in Shandong province is lower than in all country. Strong snowfall and snowfall intensive are favorable to form deep snow cover without melt snowfall, especially for air temperature and ground temperature higher than 0℃. More lower air temperature and ground temperature will benefit snow cover. The value of ground temperature threshold is about 0℃ when snow cover begin to form. The common character is that ground temperature drops quickly before visible snow cover and rises stably after 1 to 2 hours . Air temperature is usually below 0℃ when snow cover forms, or major snowfall will melt. Small wind speed is good for snow cover.
Key words: Jianghuai cycle, snowstorm, snow cover, influence factor