基于SPEI的南盘江流域近40年冬春干旱时空特征研究

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。

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

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 degree,period and spatial distribution.The results showed that annual SPEI had the decreasing trend and had the periods of 6years and 10years;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 region,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.