基于Z指数与SPI的北京市干旱特性分析

Drought characteristics analysis of Beijing based on Z index and SPI

选用北京站作为北京市代表站,根据历年降水量资料分别计算了年降水量的Z指数以及SPI值,对不同方法分别判断了北京站的干旱年份和旱涝等级,结果表明:Z指数方法共识别12年为干旱,其中7年为轻度干旱、 4年为中度干旱、 1年为重度干旱; SPI方法共识别11年为干旱,其中5年为轻度干旱、 6年为中度干旱。Z指数方法对于干旱的识别更为严格,且与调查结果较为一致。

In this study,Beijing precipitation station is chosen to analyze its drought characteristics.The Z index and SPI of its yearly precipitation are both calculated.According to the classification scales for Z index and SPI,the selected years in the time scales areclassified as drought or flood and so on.It is concluded that,according to the method of Z index,there are 12 years classified as drought,in which 7years as light drought,4 years as moderate drought and 1year as serious drought;according to SPI method,there are 11 years classified as drought,in which 5 years as light drought and 6 years as moderate drought.This means the method of Z index is stricter than SPI.And this method is more consistent to the investigation result.