柳州2020年一次“龙舟水”成因及预报偏差分析  

Causality analysis of the infrequent and forecasting deviation Dragon-Boat precipitation in Liuzhou city in 2020

作　　者：张凌云 刘蕾 Zhang Lingyun;Liu Lei(Liuzhou Meteorological Bureau,Liuzhou Guangxi 545001,China)

机构地区：[1]柳州市气象局,广西柳州545001

出　　处：《气象研究与应用》2022年第3期67-71,共5页Journal of Meteorological Research and Application

基　　金：广西重点研发计划项目(桂科AB19110028);2021年柳州市气象科研计划项目(柳气科202103)。

摘　　要：利用FNL再分析资料、高空和地面观测资料及数值模式资料,对柳州市2020年6月24—26日的“龙舟水”成因和预报偏差进行了诊断分析。结果表明:(1)此次“龙舟水”过程可划分成前期北部的暖区暴雨和后期南部的持续暴雨阶段;(2)在暖区暴雨阶段,地面中尺度辐合线是暴雨触发的重要机制,迎风坡地形抬升和喇叭口地形收缩对暖区暴雨有增辐作用;(3)在持续暴雨阶段,地面静止锋、中尺度辐合线是暴雨触发和维持的重要天气系统,低层强盛的西南气流和急流脉动为持续暴雨提供源源不断的水汽、能量供应和水汽辐合条件;(4)数值模式对低层切变线、地面冷空气和中尺度辐合线的预报偏差是导致暴雨落区预报偏差重要原因。Based on FNL reanalysis data, high-altitude and ground observation and numerical model data,the causes and forecast deviation of Dragon-Boat Precipitation in Liuzhou city from June 24 to 26,2020 were analyzed. The results show that:(1)the Dragon-Boat Precipitation process can be divided into two stages: the warm-area rainstorm in the north in the early stage and the continuous rain in the South In the later stage;(2)In the warm-region rainstorm stage, the surface mesoscale convergence line is an important mechanism for triggering the rainstorm, and the topographic uplift of the windward slope and the topographic contraction of the bell mouth is conductive to the increase of the warm-region rainstorm;(3)In the stage of continuous rainstorm, the surface stationary front and mesoscale convergence line are important weather systems, triggering and maintaining the rainstorm. The strong southwest air flow and jet pulsation at the lower level provide continuous water vapor,energy supply and water vapor convergence conditions for the continuous rainstorm;(4)The prediction deviations of the numerical model for the low-level shear line, the surface cold air and the mesoscale convergence line are the important reasons for the prediction deviation of the rainstorm area.

关 键 词：龙舟水 中尺度辐合线 急流脉动 

分 类 号：P426.6[天文地球—大气科学及气象学]