| 一次有冷空气侵入的梅汛期大暴雨过程诊断分析 |
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| 引用本文： | 蓝俊倩,张浩川,徐月飞.一次有冷空气侵入的梅汛期大暴雨过程诊断分析[J].气象与环境科学,2018,41(3):73-82. |
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| 作者姓名： | 蓝俊倩 张浩川 徐月飞 |
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| 作者单位： | 衢州市气象局;中国人民解放军94855部队气象台 |
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| 摘 要： | 利用常规观测资料、NCEP 1°×1°再分析资料及雷达资料,对2014年6月浙江中部地区一次有冷空气侵入的梅汛期大暴雨过程进行了诊断分析。结果表明:短波槽携带冷空气与西南暖湿气流交汇所形成的低涡切变是大暴雨过程主要影响系统;冷空气侵入使垂直方向上形成上冷下暖的不稳定结构,在暴雨区域上空始终对应有配合垂直上升运动中心的低层辐合中心,同时800-900 h Pa的干冷平流向低层的输送对暴雨维持有重要作用。冷空气侵入加剧了低层大气的对流性不稳定,大暴雨的产生与低层大气对流性不稳定的加剧和不稳定能量的释放有密切关系。湿位涡正压项(MPV1)表明大气处于对流不稳定状态,斜压项(MPV2)由负转正发展使垂直涡度得到较大增长,从而为暴雨提供了很好的垂直动力条件。根据雷达速度图上高低层冷暖平流及实况反射率回波,可以初步判断降水的强弱和发展趋势。
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| 关 键 词： | 大暴雨 冷空气 湿位涡 雷达图 |
Diagnostic Analysis of a Heavy Rainfall Process During Meiyu Period Caused by Cold Air Intrusion |
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| Lan Junqian,Zhang Haochuan,Xu Yuefei.Diagnostic Analysis of a Heavy Rainfall Process During Meiyu Period Caused by Cold Air Intrusion[J].Meteorological and Environmental Sciences,2018,41(3):73-82. |
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| Authors: | Lan Junqian Zhang Haochuan Xu Yuefei |
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| Abstract: | By using conventional observation data,NCEP 1 ° × 1 ° reanalysis data and radar data,a heavy rainfall process caused by cold air intrusion happened in June 2014 during Meiyu period were diagnosed and analyzed.Results were as follows.The main influence system of this process was low vortex shear,which caused by cold air of the shortwave trough met with warm air of southwest airflow.Intrusion of cold air made the vertical structure unstable,mainly presented as cold advection in the upper air and the warm advection in the lower level.Over the heavy rain region,there always was a vertical upward motion center corresponding to lower level convergence center.Meanwhile,the transportation of dry cold advection to the low level between 800900 hPa played an important role in the maintenance of the heavy rain.The intrusion of cold air exacerbated convective instability in the lower atmosphere.The heavy rainfall process was closely related to the convective instability exacerbating and unstable energy releasing in the lower atmosphere.Moist potential vorticity positive items(MPV1)indicated atmospheric convection was in an unstable state.Baroclinic term(MPV2)developing from negative to positive indicated the vertical vorticity was greatly increased,which provided good vertical dynamic condition to the heavy rain.According to the cold and warm advection in different vertical levels associated with the reflectivity echo in radar speed charts,the intensity and trends of precipitation can be preliminarily determined. |
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| Keywords: | heavy rainfall cold air moist potential vorticity radar chart |
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