2013年3月20日三明市大范围冰雹过程分析

利用常规观测资料、Micaps资料、三明市区域站加密资料以及多普勒雷达资料，对2013年3月20日三明市大范围冰雹大风过程进行诊断分析。结果表明：500hPa高空槽加深、南支槽东移、三层强劲西南急流、中低层的低涡切变及弱冷空气南下、地面锋面低槽等是该次冰雹过程的主要影响系统。冰雹的发生需要较强的垂直温度梯度t850-500≥25℃，上干下湿，冰雹的0℃层高度约3．5～4．3km左右，一20℃层约在7．0～7．8km左右，低层比湿q≥10g／kg。地面气象要素的剧烈变化对强天气的发生具有一定的指示意义。850hPaθse高能舌向降雹区输送不稳定能量，低层水汽充沛，地面冷空气南下渗透触发了不稳定能量的释放使得中尺度对流天气发生发展。该次冰雹过程强度强、范围大，对流回波（飑线）呈带状自西而东影响三明市。

The Wide Range of Hail Process Analysis in Sanming on 20 March 2013

Using conventional observations, MICAPS data, intensively observed data from stations of the Sanming area and Doppler radar data, diagnostic analysis is done of the wide range of hail and strong winds process in Sanming on 20 March 2013. The results showed that a deepening 500 - hPa upper - level trough, an eastward - moving southem trough of the westerlies, three layers of strong southwesterly jets, mid - and lower - level vortex - shear and weak, southward - moving cold air and a ground frontal trough are the main system affecting the hail process. The occurrence of hail needs a strong vertical temperature gradient T850 - 500 ≥ 25 ℃, a dry upper level versus a wet low level, a 0 ℃ layer at heights from about 3.5 - 4. 3 kin, a - 20 ℃layer height about 7.0 - 7.8 km around, and a low - level specific humidity of q ≥ 10 g/ kg. Dramatic changes in meteorological elements have certain implications for the occurrence of severe weather. The delivery of instability energy by a 850 - hPa θse energy tongue to the hail area, the abundant low - level moisture and the release of instability energy by southward - penetrating cold air are responsible for the development of mesoscale convective weather. The hail was intense and extensive, with a stripe - shaped convective echo sweeping across the city from west to east.