Precipitation Evolution from Plain to Mountains during the July 2023 Extreme Heavy Rainfall Event in North China  

作　　者：Mingxin LI Jisong SUN Feng LI Chong WU Rudi XIA Xinghua BAO Jinfang YIN Xudong LIANG 

机构地区：[1]State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,China Meteorological Administration,Beijing 100081

出　　处：《Journal of Meteorological Research》2024年第4期635-651,共17页气象学报（英文版）

基　　金：Supported by the National Key Research and Development Program of China (2022YFC3003903);National Natural Science Foundation of China (42005008);Joint Research Project for Meteorological Capacity Improvement (23NLTSZ007);Basic Research Fund of Chinese Academy of Meteorological Sciences (2023Z001)。

摘　　要：North China experienced devastating rainfall from 29 July to 1 August 2023,which caused substantial flooding and damage.This study analyzed observations from surface rain gauges and S-band dual-polarization radars to reveal the following unique features of the precipitation evolution from the plain to the mountains during this event.(1) The total rainfall was found concentrated along the Taihang Mountains at elevations generally > 200 m,and its spatiotemporal evolution was closely associated with northward-moving low-level jets.(2) Storms propagated northwestward with southeasterly steering winds,producing continuous rainfall along the eastern slopes of the Taihang Mountains owing to mountain blocking,which resulted in the formation of local centers of precipitation maxima.However,most rainfall episodes with an extreme hourly rainfall rate(HRR),corresponding to large horizontal wind shear at low levels,actively occurred in the plain area to the east of the Taihang Mountains.(3) The western portion of the extreme heavy rain belt in the north was mainly caused by long-lasting cumulus–stratus mixed precipitation with HRR< 20 mm h~(-1);the eastern portion was dominated by short-duration convective precipitation with HRR > 20 mm h~(-1).The contributions of convective precipitation and cumulus–stratus mixed precipitation to the total rainfall of the southern and middle rain belts were broadly equivalent.(4) The local HRR maxima located at the transition zone from the plain to the mountains were induced by moderate storm-scale convective cells with active warm-rain processes and large number of small-sized rain droplets.(5) During the devastating rainfall event,it was observed that the rainfall peaked at around 1800 local time(LT) every day over the upstream plain area(no diurnal cycle of rainfall was observed in relation to the accumulated rainfall centers over mountain areas).This was attributable to convective activities along the storm propagation path,which was a result of the more unstable stratification with

关 键 词：extreme rainfall from plain to mountains convective precipitation stratiform precipitation hourly rainfall rate low-level jet diurnal variation 

分 类 号：P426.614[天文地球—大气科学及气象学]