滇中地区的短时强降水时空分布特征

TEMPORAL AND SPATIAL CHARACTERISTICS OF FLASH HEAVY RAIN IN CENTRAL YUNNAN

利用滇中地区2000—2021年31个国家站逐时降水资料,分析了滇中地区短时强降水(Flash Heavy Rain,FHR)时空分布特征。结果表明:各统计标准的FHR事件月累积频次都表现为单峰型,主要集中在5—10月,尤其是6-8月为HFR事件高发期。FHR次数越多,雨季FHR年均雨量越多,FHR对滇中地区雨季雨量的贡献率就越高。18时至次日凌晨4时许是FHR事件高发时段,凌晨1时是最高峰值。无论哪个等级的FHR事件,昆明市区及周边地区都是“夜雨”高发高强区,说明大城市热岛效应以及特殊地形会对局地降水产生明显影响,而其他时段的FHR事件空间分布和平均雨强分布则表现出比较散乱的分布特征,说明了FHR事件的突发性和局地性。

Based on the hourly precipitation data of 31 national stations in Central Yunnan from 2000 to 2021,the temporal and spatial distribution characteristics of flash heavy rain(FHR)in Central Yunnan were analyzed.The results showed that the monthly cumulative frequency of FHR events of all statistical criteria showed a single peak type,mainly concentrated in May to October,especially in June to August,which was the peak period of HFR events.The greater the frequency of FHR,the greater the average annual rainfall of FHR in the rainy season,and the higher the contribution rate of FHR to the rainy season rainfall in Central Yunnan.The FHR events had a high incidence period from 18pm to 4am the next day,with the highest peak at 1am.No matter what level of FHR events,Kunming City and surrounding areas were high incidence and high strength area of the night rain.This illustrates big city heat island effect and special topography can obviously influence on the local precipitation.However,the spatial distribution of FHR events and the average rainfall intensity distribution in other periods showed relatively scattered distribution characteristics,indicating the FHR events were sudden and local.