热带气象学报2026，Vol.42Issue(2)：165-175,11.DOI:10.16032/j.issn.1004-4965.2026.014
受地形影响的广西沿海前汛期降水日变化特征及成因
Characteristics and Mechanisms of Diurnal Variations of Precipitation During Pre-flood Season over Guangxi Coastal Region Influenced by Topography
摘要
Abstract
This study investigates the characteristics of diurnal variations of precipitation during pre-flood season(April-June)over the Guangxi coastal region,using hourly precipitation data from national surface meteorological observatory stations and regional automatic weather stations,as well as ERA5 hourly reanalysis data from 2010 to 2022.Based on the K-means clustering algorithm applied to diurnal precipitation patterns,the study area was divided into three sub-regions:Region 1 in the Shiwan Mountains and their northern regions,Region 2 along the coastline and in the adjacent flat terrain,and Region 3 in the Liuwan Mountains.After analyzing the physical mechanisms driving these peak characteristics,the key findings are as follows.(1)Diurnal variations in precipitation amount,frequency,and intensity are strongly influenced by topography.The diurnal precipitation exhibits three distinct patterns:a bimodal pattern with morning and afternoon peaks,a single morning peak,and a single afternoon peak.Both daily precipitation amount and intensity decrease from the coastal to the inland areas.The peak phases of precipitation amount and frequency are delayed by 3-4 hours propagating from the southwest to the northeast.(2)Region 1,located near the coast at a relatively high elevation,is jointly influenced by land-sea breezes,mountain thermal circulation,and nocturnal low-level jets.Although this region features lower overall precipitation amounts and weaker intensity,it exhibits the highest frequency of nighttime precipitation.Strong nocturnal southward moisture transport interacts with orographic uplift,generating frequent but weak precipitation at night.Conversely,afternoon heating of the terrain triggers local convective activity,forming a double-peak pattern.(3)Region 2 shows a single morning peak driven by intensified low-level moisture convergence and land breezes during nighttime to early morning.The western part of this region is significantly influenced by the blocking effect of the Shiwan Mountains,with enhanced orographic lifting leading to higher precipitation amounts and stronger intensity.(4)Region 3 is characterized by a pronounced afternoon peak of convective precipitation.The inland penetration of the afternoon sea breeze and terrain-induced thermal updrafts generate a robust local vertical thermal circulation.This mechanism destabilizes the atmospheric stratification,leading to intense and frequent afternoon convective rainfall,with the maximum precipitation intensity primarily occurring at noon.关键词
广西沿海/前汛期降水/日变化/K均值聚类算法Key words
Guangxi coastal region/pre-flood season precipitation/diurnal variations/K-mean clustering algorithm分类
天文与地球科学引用本文复制引用
何莉阳,原韦华,赖晟,覃卫坚,陆虹,欧春苗,周秀华..受地形影响的广西沿海前汛期降水日变化特征及成因[J].热带气象学报,2026,42(2):165-175,11.基金项目
广西自然科学基金项目(2024GXNSFBA010025) （2024GXNSFBA010025）
广西自然科学基金项目(2024GXNSFBA010297) （2024GXNSFBA010297）
国家自然科学基金项目(42065004) （42065004）
广西气象科研计划项目(桂气科2023ZL05) （桂气科2023ZL05）
柳州市元宝山地形暴雨重点实验室项目(2024ybssysz1)共同资助 （2024ybssysz1）
