广东省前汛期大到暴雨频数的时空变化特征

Spatiotemporal Variations of Heavy Rain's Frequency in the Early Rainy Season in Guangdong

利用实测降水量资料研究了广东前汛期大到暴雨频数的时空分布特征,分析结果表明:广东前汛期大到暴雨频数与同期雨量的空间分布具有很好的一致性,基本可以表征前汛期的旱涝程度,通过REOF可将其分为4个区:粤东区、珠江三角洲区、粤西北区和雷州半岛区;前汛期大到暴雨频数的年际变化明显,主要有准2～3 a、6～10 a周期,1985年后各区周期均有缩短趋势,以4～5 a短周期为主;珠江三角洲及以南地区前汛期大到暴雨频数有增多趋势,其中珠江三角洲中心区域增多显著,6月份变化最明显。

Based on the observed data of precipitation in Guangdong Province, the characteristics of spatio- temporal variations of heavy rain in early rainy season （April--June） were studied. The results show： （1） The spatial distribution of heavy rain frequency is consistent with the rainfall and has obvious regional characters. The heavy raiil frequency can represent the drought and flood trend in the early rainy season. By REOF method, the heavy rain distribution can be divided into 4 regions. East Guangdong, the Pearl River Delta region, Northwest Guangdong and Leizhou Peninsula. （2） The main periods in the frequency variation of heavy rain are 2-3 a and 6-10 a. The period of each region has shortened since 1985, with the main period of 4-5 a. （3） The frequency of heavy rain in the Pearl River Delta and the region south to it has an increasing trend, which is more obvious in the center of Peal River Delta region, and passed a confidence level test at 0.05. The most obvious change happened in June.