高级搜索

2024年2月湖北省一次大范围冻雨过程的宏微观特征及形成机制初探

Study on the macro and micro characteristics of a large-scale freezing rain weather event in Hubei Province

  • 摘要: 2024年2月长江中下游地区先后出现两次低温雨雪冰冻天气,其中第一次过程(2月1—6日)冻雨表现出量大、范围广、持续时间长、危害性强等特征。为此,基于湖北省80个国家气象站激光雨滴谱仪观测数据,结合气象要素观测资料,对此次冻雨过程进行定量判断,并对其宏微观特征进行定量分析,结果表明:(1) 此次过程冻雨区主要集中在江汉平原和武汉城市圈等地,表现为液态降水维持时间长。(2) 冻雨时数和冻雨量分布具有较好的一致性,其高值区均呈现西北-东南走向,冻雨时数一般在15 h以上,冻雨量超过24 mm;冻雨集中期在2月2—3日,此时段各区间其数浓度、液水含量、雨强和粒径站时数占比均显著高于该过程其他时段。(3) 各地区平均冻雨滴谱分布呈单峰型,其峰值数密度在200 mm-3·mm-1左右。(4) 构建的Z-R关系不同于短历时、区域性冻雨过程,能较好地实现对此类冻雨定量估测降水(Quantitative Precipitation Estimation QPE)的估算。整个过程中质量加权平均直径(Dm)和归一化截距参数(log10Nw)的平均值分别为1.07 mm和3.03。(5) 在水汽凝华、丛集和凇附机制的共同影响下,致密霰粒和冰晶聚合物融化形成此次冻雨过程。

     

    Abstract: In February 2024, two rounds of low temperature,rainfall/snowfall and freezing weather occurred in the middle and lower reaches of the Yangtze River.The first round of the event from February 1 to 6.Showed characteristics such as a large amount of freezing rain,wide range,long duration,and severe hazard.Based on the observation data of laser raindrop spectrometers from 80 national meteorological stations in Hubei Province,and combined with meteorological element observation data,this study quantitatively identified frozen rain and analyzed its macro and micro characteristics.The results are as follows.(1) During this rainfall/snowfall and freezing weather process,frozen rain mainly occurred in areas such as the Jianghan Plain and the Wuhan urban area,characterized by long-term maintenance of liquid precipitation.(2) The distribution characteristics of freezing rain hours and freezing rain amounts were consistent,with high-value areas positioned along the northwest-southeast direction.The duration of freezing rain was generally longer than 15 hours,while the freezing rain amount exceeded 24 mm.The peak period for freezing rain appeared from February 2 to 3 in 2024, with the proportion of numerical concentration,liquid water content,rain intensity,and particle size station hours in each interval significantly higher than in other periods.(3) The average spectrum of frozen rain droplets in various regions showed an unimodal distribution,with the peak number density around 200 mm-3mm-1.(4) The constructed Z-R relationship was different from short-term,regional frozen rain processes.It could effectively estimate the quantitative precipitation estimation (Quantitative Precipitation Estimation,QPE) of such frozen rain.The average values of Dm and log10Nw throughout the entire process were 1.07 mm and 3.03 mm,respectively.(5) This freezing rain process was mainly influenced by the combined effects of water vapor condensation,clustering,and glaze attachment mechanisms,and formed by the melting and formation of dense graupel particles and ice crystal polymers.

     

/

返回文章
返回