青海省甘德两次降雪过程的微气象特征分析

利用青海省甘德两次降雪过程的微气象观测数据,探讨了两场降雪过程雪深、雪密度、雪中含冰量、雪中含水量和雪面温度的变化情况,分析了地表反照率与雪密度、雪中含冰量及雪中含水量的关系,结合降雪过程近地面温、湿、风廓线特征分析了积雪对近地面温、湿、风梯度的影响。结果表明:积雪覆盖会导致地表反照率显著增加,降雪过后正午时地表反照率可高达0.8～0.9。随着积雪的消融,地表反照率逐渐减小;积雪反照率与雪密度和雪中含冰量呈正相关,与雪中含水量呈负相关;地表积雪覆盖会导致近地面温度梯度绝对值减小,相对湿度梯度绝对值在凌晨减小、午后增大,地表积雪覆盖对近地面风速梯度变化并无特定的影响。

Micro-Meteorological Characteristics Analysis of Two Snowfall Processes in Gande of Qinghai Province

Using observed micro-meteorological data of two snowfall processes in Gande of Qinghai Province, the snow depth, snow density, ice content in snow, water content in snow and snow surface temperature are discussed, and the relationships between surface albedo and snow density, ice content in snow, water content in snow are analyzed. Besides, the influence of accumulated snow on air temperature gradient, relative humidity gradient and wind speed gradient of snow cover are also analyzed. The results show that surface albedo increases obviously while ground is covered by snow. Albedo can be 0.8-0.9 at noon after snowfall. Albedo reduces along with snow melting. Snow albedo is positively related with snow density and ice content in snow and negatively related with water content in snow. Snow cover reduces absolute value of air temperature gradient. The absolute value of relative humidity gradient gets lower at dawn and higher at noon. Snow cover has no effect on wind speed gradient.