基于小时雨量的防城港市短时强降水特征分析

Characteristics of Short-term Intense Rain in Fangchenggang City Based on Hourly Rainfall Data

基于2016-2019年防城港市自动气象站小时雨量,结合地形分析短时强降水时空分布特征,结果表明:十万大山南北两侧短时强降水次数从北到南递增,大值区位于十万大山南侧的迎风坡及喇叭口地形;各月的短时强降水的分布有差异,短时强降水主要发生在4-9月,6月短时强降水分布不均匀,7-8月短时强降水最强盛;受对流日变化、低空急流、海陆风等影响,短时强降水日变化特征明显,前汛期市南部短时强降水高峰期出现在清晨、市北部出现在凌晨和午后,后汛期市南部出现在清晨和午后、市北部出现在午后到傍晚,非汛期短时强降水出现的时段呈多峰值态势。

Based on the hourly rainfall data from automatic weather stations in Fangchenggang from 2016 to2019,the spatial and temporal distribution of short-term intense rain with specific topography is analyzed.The result is shown as follows.The frequency of short-term intense rain increases from north to south across the Shiwandashan;the large-value areas centers in the windward slope on the south side of Shiwandashan and bellmouthed terrain;short-term intense rain mainly occurred from April to September,with an uneven distribution in June and being strongest in July-August;affected by convection diurnal variation,low-level jet stream and sea-land wind,the diurnal variation characteristics are obvious.In general,in the South of Fangchenggang,the peak period of short-term intense rain occurred in the early morning in the first raining season(April through June),while occurred in early morning and afternoon in the second raining season(July through September);in the North of Fangchenggang,the peak period of short-term intense rain occurred in the early morning and afternoon in the first raining season,while the peak period of short-term intense rain occurred from afternoon to evening in the second raining season;in non-flood season,the period of short-term intense rain presents a multi-peak trend.