贵阳机场降雪气候特征及一次低温雪凝天气成因分析
Analysis of the Climatic Characteristics of Snowfall at Guiyang Airport and the Causes of a Low Temperature Snowy Condensation Weather

本文利用贵阳机场地面观测资料、ECMWF ERA5再分析资料，分析了贵阳机场降雪气候特征及2022年2月21日~22日降雪过程，结果表明：1) 2008~2022年贵阳机场降雪年际变化特征明显，降雪日数整体呈缓慢减少趋势，年平均降雪日数为8天；降雪多集中在冬季、出现时间集中在23时到次日12时(北京时)；2) 此次降雪是在有利的环流背景下发生的；3) 降雪期间相对湿度大于90%的湿度层达到400 hPa以上，且云顶温度达到？25℃、整层为冷性结构；4) 降雪期间中低层700 hPa~850 hPa间水汽通量散度均小于0、水汽辐合，湿度较大，期间垂直速度均小于等于0，上升运动显著，为降雪提供了有利的水汽和动力条件。
Using Guiyang Airport ground observation data and ECMWF ERA5 reanalysis data, this paper analyzes the climatic characteristics of snowfall at Guiyang Airport and the snowfall process from Feb-ruary 21~22, 2022. The results show that: 1) the interannual variation characteristics of snowfall at Guiyang Airport from 2008 to 2022 are obvious, and the overall number of snowfall days shows a slow decreasing trend, with an annual average of 8 snowfall days; snowfall is mostly concentrated in winter and occurs from 23:00 to 12:00 the next day (Beijing time); 2) this snowfall occurred under favorable circulation conditions; 3) during the period of snow, the humidity layer with relative humidity greater than 90% reached more than 400 hpa, and the cloud top temperature reached ？25？C. The whole layer is a cold structure; 4) the divergence of water vapor flux between 700 hPa and 850 hPa in the middle and lower layers is less than 0 at 00:00 during the period of snow. The moisture convergence humidity is large, and the vertical velocity is less than or equal to 0 during this period. The upward movement is significant, providing favorable water vapor and dynamic conditions for snowfall.