2023年河南平顶山一次暴雪天气成因分析

Cause Analysis of the Snowstorm Occurring in Pingdingshan, Henan Province in 2023

摘要: 利用观测资料、ERA5逐小时再分析、风廓线雷达等数据，文章对2023年3月河南平顶山的一次暴雪天气成因进行分析。结果表明：1) 此次雨雪过程是在低槽东移发展、槽前强盛西南急流与东路强冷空气结合的有利背景下形成的，具有雨雪量大、雨雪相态复杂、局部积雪深、降温幅度大的特点，暴雪中心汝州降雪量28.4 mm，最大积雪深度16 cm；2) 强降雪期间700~500 hPa有西南急流强水汽输送和水汽辐合，水汽通量和水汽通量散度最大值分别超过9 g∙cm⁻¹∙hPa⁻¹∙s⁻¹和−16 × 10⁻⁷ g∙hPa⁻¹∙cm⁻²∙s⁻¹，700 hPa以下垂直上升运动与强的水汽输送和水汽辐合，有利于暴雪天气的发生；3) 风廓线雷达在雨雪过程中呈现出河南省典型“天南地北”的天气形势，降水相态转纯雪时，低层东北气流扩展到了1000~1500 m高度；风廓线垂直速度可以反映出降水开始、相态转换等特征，对临近预报具有一定指导意义；4) 雷达回波演变特征可以反映出雨雪开始、维持、减弱的变化。强降水期间回波中心强度最大超过45 dBz，并长时间维持在30~35 dBz；平均径向速度图上1.5 km和5 km高度各有一对正负速度中心，最大速度分别为12 m/s和17 m/s，反映出了此次雨雪过程中高低空急流。

Abstract: Based on the observational data, ERA5 hourly reanalysis data and wind profile radar, the causes of a snowstorm in Pingdingshan, Henan Province in March 2023 were analyzed in this paper. The results show that: 1) The rain and snow process was formed under the favorable background of the eastward development of the trough, the combination of strong southwest jet in front of the trough and strong cold air on the east road. It had the characteristics of large amount of rain and snow, complex rain and snow phase, large local snow depth, and sharp temperature drop. The snowfall in the snow center of Ruzhou is 28.4 mm, and the maximum snow depth is 16cm. 2) During the period of strong snowfall, there were strong water vapor transport and water vapor convergence in the southwest jet. The maximum water vapor flux and water vapor convergence exceeded 9 g∙cm⁻¹∙hPa⁻¹∙s⁻¹ and −16 × 10⁻⁷g∙hPa⁻¹∙cm⁻²∙s⁻¹, respectively. The vertical upward movement below 700 hPa, strong water vapor transport and water vapor convergence are conducive to the occurrence of blizzard weather. 3) In the process of rain and snow, wind profile radar presents a typical weather situation of “the Flow Field Configuration of Top South Airflow and Lower the North Airflow” of Henan Province. When the precipitation phase turned to pure snow, the low-level northeast air flow extended to a height of 1000~1500 m. The vertical velocity of the wind profile can reflect the characteristics of precipitation onset and phase transition, which had a certain guiding significance for forecasting. 4) The evolution characteristics of radar can reflect the changes in the beginning, maintenance and weakening of rain and snow. During heavy precipitation, the maximum radar echo exceeded 45 dBz, and remained at 35~45 dBz for a long time. The average radial velocity diagram has pair of positive and negative velocity centers at the height of 1.5 km and 5 km respectively, and the maximum velocity are 12 m/s and 17 m/s, respectively, which reflected the high and low level jet stream during the rain and snow process.