Distinct Mechanisms Governing Two Types of Extreme Hourly Rainfall Rates in the Mountain Foothills of North China During the Passage of a Typhoon Remnant Vortex from 30 July to 1 August 2023  

作　　者：Rudi XIA Yuqing RUAN Jisong SUN Xudong LIANG Chong WU Feng LI Ju LI Jinfang YIN Xinghua BAO Mingxin LI Xiaoyu GAO 

机构地区：[1]State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081,China [2]Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science&Technology,Nanjing 210044,China [3]Institute of Urban Meteorology,China Meteorological Administration,Beijing 100089,China [4]Research Center for Disastrous Weather over Hengduan Mountains&Low-Latitude Plateau,China Meteorological Administration,Kunming 650034,China

出　　处：《Advances in Atmospheric Sciences》2025年第4期761-779,共19页大气科学进展(英文版)

基　　金：supported by the National Key R&D Program of China(2022YFC3003903);Natural Science Foundation of Beijing(Grant No.8222079)and of China(Grant No.42475014,U2442204);the Basic Research Fund of CAMS(2023Z001).

摘　　要：This study investigates extreme rainfall episodes along the eastern foothills of the Taihang Mountains in North China from 30 July to 1 August 2023.It focuses on two types of extreme hourly rainfall rates(HRRs),i.e.,the maximum regionalaverage HRR and site-observed HRR,which exhibited sequential development over southern,middle,and northern key regions.These rainfall extremes occurred in an environment where a high-pressure barrier over North China prevented the intrusion of cold air masses from the north while a northward-moving typhoon remnant vortex and its associated low-level jet(LLJ)transported warm and moist airflow from the south.Two distinct echo evolution modes and convection initiation mechanisms are identified for the two types of extreme HRRs.The maximum regional-average HRR occurred when the LLJ arrived to the east of the key regions,while the maximum site-observed HRR occurred when the warmer vortex center influenced the regions.Taking the northern key region as a representation,at the time of the maximum regional-average HRR,slantwise ascent of the airflow along a warm-frontal-like boundary released energy related to symmetrical instability,resulting in stratiform rainfall with weak convective cores.The transport of locally initiated convection over the eastern plain region,where the atmospheric stratification was more potentially unstable,also significantly contributed.When the maximum site-observed HRR occurred,the terrain lifting of warm and moist southeast airflow led to intense convection over the mountain foothills.Overall,the passage of the warm-core typhoon remnant vortex and interaction with Taihang Mountains determined the timing and location of extreme HRRs across the key regions.

关 键 词：extreme rainfall hourly rainfall rate MOUNTAIN VORTEX mechanism 

分 类 号：P444[天文地球—大气科学及气象学] P426.62