基于标准化降水蒸散指数的长江流域旱涝情势演变

基于长江流域133个气象站1970-2012年实测逐月降水量和月平均气温资料,计算不同时间尺度上的标准化降水蒸散指数序列,研究近几十年来长江流域旱涝情势的时空演变特征。结果表明,1970-2012年长江流域整体干旱形势不严重,但是干旱化的趋势比较明显。与长江上游地区相比,长江中下游区域的干旱趋势表现得更加突出,特别是长时间尺度上的干旱趋势非常明显。针对典型极端气象事件分析发现,标准化降水蒸散指数能够反映出不同时间尺度上长江流域发生的旱涝事件,表明该指数对于准确评估长江流域的旱涝程度和分布范围具有很好的指示性意义。

Study on the evolution of droughts and floods in the Yangtze River basin based on the standardized precipitation evapotranspiration index

In order to investigate the change tendencies of the droughts and floods in the Yangtze River basin, we used the standardized precipitation evapotranspiration index on multiple time scales, based on the monthly precipitation and average temperature data from the 133 meteorological stations in the whole basin during 1970-2012. The results showed that the overall drought conditions in the Yangtze River basin were not serious, while the drought tendency was prominent. Compared to the upstream region, the middle and lower reaches of the Yangtze River basin had a more prominent drought tendency, especially on longer time scales. In addition, the analysis of typical extreme meteorological events showed that the standar dized precipitation evapotranspiration index could well reflect the floods and droughts in the Yangtze River basin on different time scales. This suggests that the index can be used to precisely evaluate the extents and distributions of the hydrological regimes in this basin.