首页|辽东半岛两次由微湿下击暴流引发的雷暴大风过程对比分析

辽东半岛两次由微湿下击暴流引发的雷暴大风过程对比分析

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选用大连市和丹东市SA多普勒天气雷达资料,结合地面观测和ERA5 再分析资料,对比分析 2020 年 9 月 11 日(过程Ⅰ)和2021 年9 月10 日(过程Ⅱ)辽东半岛两次微湿下击暴流天气过程的环流背景及成因.结果表明:两次过程均发生在东北冷涡背景下,过程Ⅰ为北上台风变性后的冷涡,过程Ⅱ为切断低压.两次过程的大气层结均为"上干下湿"的不稳定层结,探空曲线呈向上开口喇叭型,近地面温度垂直递减率接近干绝热,整层大气可降水量大于30 mm,抬升凝结高度较低,CAPE和DCAPE较小;0~6 km风切变强度为过程Ⅱ明显强于过程Ⅰ.两次过程的雷暴大风均由微湿下击暴流引发,过程Ⅰ为孤立风暴产生的微湿下击暴流,过程Ⅱ为飑线系统内嵌的微湿下击暴流.两次过程在微湿下击暴流发生前,多普勒天气雷达高仰角大于45 dBz的强反射率因子缺口均先于低仰角出现.
Comparative analysis of two thunderstorm gale events triggered by wet microbursts over the Liaodong Peninsula
The study utilizes SA Doppler weather radar data from Dalian and Dandong,combined with surface ob-servations and ERA5 reanalysis data,to conduct a comparative analysis of the synoptic background and mecha-nisms of two mild-wet downburst events over the Liaodong Peninsula:the first on September 11,2020(Event Ⅰ),and the second on September 10,2021(Event Ⅱ).Results indicate that both events occur under the influence of a Northeast Cold Vortex.Event I is associated with a cold vertex transformed from a northward typhoon,while Event Ⅱ involves a cut-off low.Both events are characterized by unstable atmospheric stratifications of"upper-wet and lower-dry",with skew-T diagrams showing an upward-opening"bell-shaped"structure.Near-surface temperature lapse rates are nearly dry-adiabatic.The precipitable water content exceeds 30 mm.The lifting condensation level is low,with CAPE and DCAPE values being relatively small.The 0-6 km wind shear intensity is significantly stron-ger in Event Ⅱ than in Event Ⅰ.The thunderstorm gale events in both cases are induced by wet microbursts,with E-vent I involving an isolated storm and Event Ⅱ embedded within a squall line system.In both cases,the Doppler ra-dar reflectivity notches exceeding 45 dBz appear earlier at higher elevation angles than at lower elevation angles prior to the wet microbursts.

Northeast Cold Vortex(NCV)Cut-off lowThunderstorm gale

贾旭轩、纪永明、段云霞、刘晓初、梁军

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中国气象局沈阳大气环境研究所,辽宁 沈阳 110166

中国气象科学研究院灾害天气国家重点实验室,北京 100081

大连市气象台,辽宁 大连 116001

辽宁省气象灾害监测预警中心,辽宁 沈阳 110166

沈阳市气象台,辽宁 沈阳 110168

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东北冷涡 切断低压 雷暴大风

2024

气象与环境学报
中国气象局沈阳大气环境研究所

气象与环境学报

CSTPCD
影响因子:1.433
ISSN:1673-503X
年,卷(期):2024.40(6)