基于SPEI的滇中季节性干旱时空特征分析

The Spatial-Temporal Distribution of Seasonal Drought in Central Yunnan Based on SPEI

【目的】干旱缺水是制约滇中发展的重要因素之一,评价滇中干旱变化规律对制定区域抗旱对策、应对干旱缺水问题十分必要。【方法】以近40年来滇中45个气象站的月降水、气温资料作为基础数据,采用降水蒸发差值(P-PET)初步衡量滇中地区水分盈亏状况,然后以标准化降水蒸发指数(SPEI)作为干旱指标计算了滇中旱季SPEI的总体变化趋势、周期特征,分析滇中地区干旱的时空变化特征。【结果】过去40年,滇中地区冬春两季、干季水分亏缺较为严重,除春季SPEI呈微弱上升趋势外,冬季、干季均以下降趋势变化;干季周期变化为11、18、29年,春季周期变化为6、12、24年,冬季为8、12、18年。滇中各季SPEI空间上具有较好的一致性,表现为总体一致型。【结论】该研究结果可为滇中地区制定抗旱策略、科学合理配置水资源提供参考依据。

[Purposes]Drought and water shortage is one of the important factors restricting the de- velopment of Central Yunnan, therefore, it is essential to evaluate drought space and time distribution for working out the drought preparedness plans.[Methods]According to the monthly data of pre- cipitation and temperature collected from 45 meteorological stations of Central Yunnan, preliminarily measured water profit and loss with P-PET and with SPEI as drought index, we analyzed the spatio- temporal characteristic based on the change of SPEI and period character.[Results]Winter, spring and dry season had a serious water deficit, dry and winter SPEI had the decreasing trend except for spring and had the periods of 11, 18, 29 years and 8, 12, 18 years;and had the periods of 6, 12, 24 years for spring. Good agreement of SPEI in space showed general uniform type.[Conclusion]The results of the study can provide a reference for the establishment of drought resistance strategy and the rational allocation of water resources.