安徽省积雪效率和积雪密度特征分析

Characteristic Analysis of Snow Cover Efficiency and Snow Density in Anhui Province

基于安徽省80个气象观测站2000年1月至2018年2月的积雪深度、降水量、雪压和日平均气温等资料,分别统计分析了安徽省不同区域的积雪效率和积雪密度特征,结果表明:不区分地面前期有无积雪时,全省积雪效率平均为0.75 cm·mm^(-1),地面前期有积雪时的积雪效率大于前期无积雪时的积雪效率,地面前期有积雪的降雪事件积雪效率为0.81 cm·mm^(-1),前期无积雪的降雪事件积雪效率为0.69 cm·mm^(-1)。整体上看,积雪效率自北向南逐渐减小,淮河以北的积雪效率明显大于江淮之间和江南的积雪效率,后两者之间的差异则较小。日平均气温在-2℃以下时,积雪效率变化不大,在1 cm·mm^(-1)左右,但地面前期有、无积雪时的积雪效率存在较明显的差异;日平均气温在-2℃以上时,积雪效率随着气温的上升呈明显减小的趋势,此时地面前期有、无积雪对其影响不大。淮河以北的积雪密度明显小于淮河以南的,降雪性质更接近于干雪,淮河以南的降雪事件含水量较高,其中江淮之间和江南的积雪密度差异较小。日平均气温0℃以下时,随气温升高积雪密度明显增大;0℃以上时,积雪密度也随气温升高而增大,但幅度明显减小。

Using the observed snow depth,rainfall,snow pressure and average daily temperature data from January 2000 to February 2018 of Anhui 80 meteorological stations,this paper analyzes the snow cover efficiency and snow density in Anhui province.The results show that the average snow cover efficiency in Anhui is 0.75 cm·mm^(-1) without distinguishing whether there is snow cover in the early stage.The snow cover efficiency of snow events with surface snow cover in the early stage is 0.81 cm·mm^(-1),and that without snow cover on the surface in the early stage is 0.69 cm·mm^(-1).Overall,snow cover efficiency decreases from north to south.The snow efficiency north of the Huaihe River is larger than in Jianghuai region and in south of the Yangtze River.When the daily average temperature is below-2℃,the snow cover efficiency is around 1 cm·mm^(-1),but it has obvious difference between the situation with and without surface snow cover in the early stage;when the average temperature is above-2℃,the snow cover efficiency decreases with the increase of temperature and at this moment the snow cover in the early stage has little influence on it.The snow density to the north of the Huaihe River is lower than in the south of the Huaihe River,and the nature of the snow is near dry snow.When the daily average temperature is below 0℃,the snow density increases obviously with the increase of temperature;when the temperature is above 0℃,the snow density also increases with the increase of temperature,but the range decreases apparently.