大气科学2025，Vol.49Issue(3)：767-784,18.DOI:10.3878/j.issn.1006-9895.2309.23080
二级地形触发的东移中尺度对流系统影响下游降水的典型个例
Typical Case of Impact of an Eastward-Propagating Mesoscale Convective System over the Second-Step Terrain on Downstream Rainfall
摘要
Abstract
A typical MCS(mesoscale convective system)forming over the second-step terrain,moving eastward,merging with convection from the eastern edge of the Qinghai-Xizang Plateau(QXP),and influencing downstream convection systems was analyzed through numerical simulations.This case occurring from 29 June to 1 July 2016,caused heavy precipitation from the middle reaches of the Yangtze River to the Yangtze-Huai River basin.This simulation successfully reproduced the eastward movement of the MCS over the second-step terrain and its merger with the convection moving eastward from the QXP,thus affecting downstream convective systems.The results revealed the spatiotemporal patterns of precipitation across the middle and lower Yangtze River regions.The evolution of the MCS is classified into four stages:Formation,propagation,merging,and weakening.Initiated by a cyclonic disturbance in the northeastern part of the Southwest vortex,the MCS formed over the western mountainous areas over the second-step terrain.Upon exiting the second-step terrain,the MCS merged with eastward-propagating convection from the QXP over downstream areas.This merging promoted the strong development of upward motion,enhanced low-level convergence,and generated a mesoscale vortex in the lower troposphere.The integration between the mesoscale vortex and the merged convection promoted their coupling and triggered heavy rainfall in the eastern plains beyond the second-step terrain.关键词
二级地形/东移中尺度对流系统/影响机理/数值模拟Key words
Second-step terrain/Eastward-propagating MCS(mesoscale convective system)/Impact mechanism/Numerical simulation分类
天文与地球科学引用本文复制引用
杨如意,张元春,孙建华,慕建利,于廷照..二级地形触发的东移中尺度对流系统影响下游降水的典型个例[J].大气科学,2025,49(3):767-784,18.基金项目
国家自然科学基金项目41975057、U2142202、62106270,高原与盆地暴雨旱涝灾害四川省重点实验室开放研究基金项目SZKT202101 National Natural Science Foundation of China(Grants 41975057,U2142202,62106270),Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province(Grant SZKT202101) （Grants 41975057,U2142202,62106270）
