急流和地形对阳江一次特大暴雨的影响  

On the Effect of a Jet Stream and Local Terrain on an Unusually Heavy Rain in Yangjiang

作　　者：钟雄蔼 杨廷春 李舒文 ZHONG Xiong-ai;YANG Ting-chun;LI Shu-wen(Meteorological Bureau of Maoming,Maoming 525000;Meteorological Bureau of Xinyi,Xinyi 525300;Meteorological Observatory of Guangdong,Guangzhou 510640;Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029)

机构地区：[1]茂名市气象局,广东茂名525000 [2]信宜市气象局,广东信宜525300 [3]广东省气象台,广东广州510640 [4]中国科学院大气物理研究所,北京100029

出　　处：《广东气象》2023年第4期25-29,35,共6页Guangdong Meteorology

摘　　要：利用中尺度数值模式WRF对2020年6月1日的阳江特大暴雨进行模拟和分析。结果表明:WRF的模拟结果很好地再现了该次暴雨的过程。通过控制试验和地形敏感性试验对比,发现将阳江及附近地区的山地移除后,降水区远离阳江地区,发生在粤西北山区。进一步分析表明,边界层急流为这次降水的发生发展提供了充沛水汽的前提条件。阳江附近山地对边界层急流的阻挡和抬升作用是降水发生发展的关键因素:一方面地形阻挡边界层急流增强相当位温水平梯度,增强对流不稳定性;另一方面,地形对边界层急流的抬升作用增强辐合上升运动产生对流。同时,边界层急流出口区配合低空急流入口区的抽吸作用,导致降水系统发展强盛。An unusually heavy rain that happened in Yangjiang on June 1,2020 is simulated and analyzed using the mesoscale numerical model of WRF.The results are shown as follows.The WRF model well reproduces the process of the rain of interest.By comparing a control test and a terrain-sensitive test,this work determines that the zone of precipitation moves far away from the area of Yangjiang and relocates in the mountainous region of northwestern Guangdong province after the removal of mountains from Yangjiang and its surrounding regions.Further studies reveal that a boundary-layer jet stream acts as a prerequisite for the genesis and growth of this unusually heavy rain by supplying abundant amount of water vapor.The blocking and lifting effect of the mountainous terrain in and around Yangjiang is essential for the genesis and growth of the rain.On the one hand,the terrain blocks the boundary-layer jet stream,intensifies the horizontal gradient of equivalent potential temperature,and increases convective instability.On the other,the terrain lifts the jet stream and enhances converging and uplifting motion to produce convection.It should also be noted that the outlet of the boundary-layer jet stream works with the sucking effect of the inlet of a low-level jet stream to cause the precipitating system to evolve rigorously.

关 键 词：天气学 WRF模式 暴雨 地形 边界层急流 低空急流 阳江 

分 类 号：P44[天文地球—大气科学及气象学]