“Top-Down-Approach”降水相态分析法在双流机场一次降雪过程中的应用

Application of “Top-Down-Approach” Precipitation Phase Analysis Method on a Snowfall Process at Shuangliu Airport

选取ERA5再分析资料和常规气象资料等多源数据,运用“Top-Down-Approach”降水相态分析法,分析了2023年1月16日双流机场降雪过程,重点探究了降水相态的预报着眼点。结果表明:(1)湿度超过85%的-12~-16℃温度层有利于枝状雪花的形成,高浓度云中冰相粒子与水相粒子重叠区有利于低融化比雪花的形成,在预报时需重点关注。(2)当湿球0℃温度层偏低时,可降低降雪预报中对地面温度的限制。(3)结合温度廓线分析,微波辐射计液态水廓线产品可以指示冰云层主要分布高度,还能反映出液态水含量在降雪过程开始前显著增强且在降雪趋于结束时提前降低的变化特征,对降雪过程有一定的指示意义。

Based on multi-source data such as ERA5 reanalysis data and conventional meteorological data,the “Top-Down-Approach”precipitation phase analysis method was used to analyze the snowfall process at Shuangliu Airport on January 16,2023,focusing on the prediction of precipitation phase.The results show that:(1) The temperature layer of-12°C~-16°C with humidity greater than 85% is conducive to the formation of dendritic snowflakes.In addition,the high concentration and overlapping areas of ice phase particles and water phase particles in clouds are conducive to the formation of snowflakes with low melting ratio.(2) Lower wet bulb 0 °C temperature zone(WBZ) conditions may appropriately reduce the limit of the ground temperature in the snowfall forecast.(3) Combined with the temperature profile,the liquid water profile product of the microwave radiometer can indicate the main distribution height of the ice-producing clouds,and the liquid water content will increase significantly before the snowfall process starts,and decrease in advance when the snowfall tends to end,which has certain indicative significance for snowfall process.