基于Z指数和SPI指数的钱塘江流域干旱时空分析

Spatial and temporal analysis of drought in Qiantang River basin based on Z index and SPI

在分析钱塘江流域11个气象站1951～2008年的月降水资料基础上,提出了多时间尺度Z指数和标准化降水指数(SPI),并通过普通Kriging方法对干旱指数进行插值,重点分析了钱塘江流域三次重大干旱的空间分布情况。研究表明,多时间尺度Z指数和SPI在计算钱塘江流域干旱情况结果大体一致,极端干旱情况Z指数更符合实际情况,而SPI计算稳定性强。该文中首次提出了多时间尺度Z指数在钱塘江流域的应用,与多时间尺度SPI进行对比分析,为以钱塘江流域为例的中国南方湿润区域的水资源评估和干旱监测提供了一定的参考价值。

We propose the use of Z index and SPI index of different time scales through an analysis on the monthly precipitation statistics at 11 weather stations for the period 1951~2008.We interpolate the drought index with an ordinary Kriging Method and focus on the spatial patterns of three major droughts that occurred in the Qiantang River basin.We find that the drought patterns derived with Z index and SPI index are nearly the same,but the results of Z index in the extreme drought conditions are closer to the actual values,while the SPI method is computationally more stable.In this paper,the Z index of different time scales for the first time is applied in the Qiantang River basin and it is compared with SPI index method.This study provides significant reference to water resources evaluation and drought monitoring in the humid regions of south China.