干旱指数在杭州市历年旱涝特征分析中的应用

为了加强杭州市的旱涝灾害监测和评估，利用5个气象站近50年的月降水资料，比较分析了Z指数和SPI计算结果的一致性与差异。采用频率分析、趋势变化特征分析和多尺度SPI分析等方法，研究了杭州市各站及各季旱涝的变化特征。研究表明：Z指数和SPI在计算杭州市旱涝情况结果基本一致；杭州市的干旱情况自西向东逐渐加重，洪涝反之；夏季与秋季易引起梅汛、台风洪涝与夏秋干旱交替出现。本文首次使用多时间尺度SPI计算杭州市的旱涝情况，为今后杭州市旱涝预测提供了一定的参考价值。

Application of Drought Indices in Historical Droughts and Flood Analysis in Hangzhou

In order to strengthen the monitoring and assessment of drought as well as flood in Hangzhou, we analyze the conformability and difference between the calculated Z index and SPI, with the aid of the data collected from 5 weather stations. Employing such methods as frequency analysis, trend analysis and multi-scale SPI, we investigate the seasonal change characteristics of drought and flood. Via the research we find that results calculated by Z index are basically the same as those by SPI. The drought in Hangzhou is becoming more serious from west to the east, but the flood is the opposite story. Meanwhile the plum flood, typhoon-induced flood and the drought often occur alternately in summer and fall. The application of multi-scale Z index in this paper is for the first time and casts the inspiration to the drought and flood predication in Hangzhou in the near future.