基于SPEI的南盘江流域近40年冬春干旱时空特征研究

Spatio-temporal Characteristic of Winter and Spring Drought Based on Standardized Precipitation Evapo-transpiration Index in Nanpanjiang Basin

以标准化降水蒸发指数(SPEI)作为干旱指标,根据SPEI的总体变化趋势、干旱覆盖范围、发生频率、周期及空间分布,分析南盘江流域冬春干旱的时空分布特征。结果表明,1971—2010年,南盘江流域年均SPEI处于下降趋势且存在6、10年的周期变化;干旱覆盖范围逐渐扩大,轻旱呈下降趋势,中旱及重旱呈上升趋势;流域各地区发生不同程度干旱,轻旱由西南向东北方向递减,重旱与之相反,中旱则以西南至东北方向中部最低;流域内冬春干旱多为中旱。

With SPEI as drought index, spatio-temporal characteristic of winter and spring droughts was analyzed based on the change of SPEI, coverage area and frequency of drought and drought of different de- gree, period and spatial distribution. The results showed that annual SPEI had the decreasing trend and had the periods of 6 years and 10 years;the coverage area of drought enlarged with the coverage area of light drought dropping,moderate and serious drought rising; a certain degree drought appeared in each re- gion, and light drought decreased from southwest to northeast, moderate drought in central section was the lowest, and the change of serious drought was contrary to light drought; moderate drought was remarkable in nanpanjiang basin.