佛山短时强降水时空特征及主要影响系统

Spatio-temporal characteristics of short-time heavy precipitation and its main synoptic systems in Foshan

利用佛山市152个自动气象观测站2012—2020年降水资料,根据强降水范围和性质,研究佛山市短时强降水的时空分布特征,并分析主要影响系统。结果表明:(1)短时强降水发生频次整体呈上升趋势,不同范围、不同性质的短时强降水时空差异性较大。局地性、区域性、突发型短时强降水主要发生在4—9月,全市性、增长型短时强降水主要发生在3—10月,持续型短时强降水5—6月发生频次最高。(2)从日变化来看,局地性、区域性呈单峰特征,全市性呈多峰特征,突发型、增长型呈双峰特征,持续型较平稳,06—09时略高,局地性、全市性和增长型短时强降水中分位值日变化较小,区域性、增长型和持续型短时强降水中分位值的日变化较大。(3)极大值出现的时间段也不相同,最大值的短时强降水是一次增长型的区域性过程。(4)空间分布上,局地性短时强降水在佛山西南部和北部发生的频次较高,全市性短时强降水发生频次的分布与之相反,而区域性短时强降水在西南部发生频次较低,增长型短时强降水发生频次高于突发型短时强降水,持续型短时强降水发生频次最低。(5)影响系统占比最大的分别是局地性、突发型短时强降水为副热带高压边缘,区域性、持续型、增长型短时强降水为热带系统,全市性短时强降水为西风槽,而西南低涡在各类中占比均最小。

Based on the precipitation data of 152 automatic meteorological observation stations in Foshan from 2012 to 2020,the spatial and temporal distribution characteristics of short-time heavy precipitation in Foshan are studied according to the range and property of heavy precipitation,and the main synoptic systems are analyzed.The results are listed as follows.(1)The frequency of short-time heavy precipitation is on the rise as a whole,and the spatial and temporal differences of short-time heavy precipitation with different ranges and properties are large.The local type,regional type,and abrupt type of short-time heavy precipitation mainly occur from April to September,the citywide type and growth type mainly occur from March to October,and the frequency of continuous type is the highest from May to June.(2)From the perspective of diurnal variation,the local type and regional type have unimodal characteristics,the citywide type has multimodal characteristics,the abrupt type and growth type are bimodal,and the continuous type is relatively stable and slightly higher from 06:00 to 09:00.The diurnal variations of the median values of the local type,citywide type,and growth type are small,while those of the regional type,growth type,and continuous type are large.(3)The periods of the maximum values are different,and the short-time heavy precipitation with the maximum value is a regional process of growth type.(4)In terms of spatial distribution,the frequency of local type is higher in the southwest and north of Foshan,while the frequency of citywide type is opposite.The frequency of regional type is lower in the southwest,the frequency of growth type is higher than that of abrupt type,and the frequency of continuous type is the lowest.(5)The edge of subtropical high is the synoptic system of the largest proportion for the local type and abrupt type,tropical system for the regional type,continuous type,growth type,and westerly trough for the citywide type,while the southwest vortex has the smallest proportion in all types.