基于PDSI指数的近40年广东干旱特征分析

Analysis of drought characteristics in Guangdong in recent 40 years based on PDSI index

利用1979年1月-2021年2月广东省86个国家气象观测站的月平均降水、气温资料以及同期的土壤有效含水量数据,应用数理统计等方法,分析广东干旱指数PDSI时空变化特征,揭示广东近40a干旱变化趋势。结果表明,近40a广东地区PDSI指数呈轻微干化趋势,降速为0.005·(10a)^(-1),2004年PDSI为-1.47,是最干旱年份。春季PDSI指数下降趋势最明显,秋季发生干旱频率最高,夏季最低。PDSI指数月趋势呈多波动现象,最低值为-2.2,出现在2004年12月。近40a干旱发生频率介于4.8%~26.1%,粤西是干旱高频地区;广东地区呈两边干化、中部湿化的变化趋势分布格局,粤西阳春干化最明显。

Based on the monthly average precipitation and temperature data of 86 national meteorological stations in Guangdong Province from January 1979 to February 2021, and the data of soil effective water content in the same period, the paper calculated the temporal and spatial variation characteristics of drought index PDSI in Guangdong by using mathematical statistics, and studied the drought variation trend in recent 40 years. The results show that the PDSI index in Guangdong shows a slight drying trend in recent 40 years, with a decline rate of 0.005 ·(10a)^(-1), and the PDSI in 2004 is-1.47, which is the driest year. The downward trend of PDSI index is the most obvious in spring, and the drought frequency is the highest in autumn and the lowest in summer. The monthly trend of PDSI index shows multiple fluctuations, with the lowest value of-2.2, which appears in December 2004. The frequency of drought in recent 40 years is between 4.8%~26.1%. Western Guangdong is a high-frequency area of drought. The distribution pattern of Guangdong shows the change trend of drying on both sides and wetting in the middle, and Yangchun in western Guangdong has the most obvious drying.