基于SPI的云南省多尺度干旱时空演变特征识别

Spatiotemporal Variation of Drought in Yunnan Province Calculated Using the Standardized Precipitation Index

【目的】识别云南省多尺度干旱的时空演变特征。【方法】基于云南省36个气象站31 a的气象数据,基于标准化降水指数(SPI),结合GIS空间分析、非参数Mann-kendall趋势检验,识别云南省多尺度气象干旱时空分布及演变特征。【结果】(1)SPI在年尺度、季节尺度均呈波动变化趋势,除春季SPI略有增长外,夏季、秋季、冬季和年尺度的SPI均表现为减小趋势,秋季SPI变幅最大,冬季变幅最小。(2)年尺度干旱频率分布在32.26%~50.00%之间,主导的干旱等级为轻微干旱和极端干旱,干旱频率高值区主要分布在文山、红河、昆明、楚雄、德宏。(3)春、夏、秋、冬4个季节的干旱频率分别为39.86%、39.83%、38.43%、41.33%,尽管季节间干旱频率差异较小,但不同季节主导性干旱等级差异较大。除春季外,各季节的主导性干旱等级均包含极端干旱。(4)年尺度上,除5个站点干旱呈增强趋势外,其余站点均无显著变化趋势;春季大部分站点干旱演变呈减小趋势,而夏季、秋季、冬季则分别有11、6、2个站点呈显著增强趋势。【结论】云南省年尺度和季节尺度干旱频率分布及演变趋势呈明显的时空分异特征,区域干旱以季节性干旱为主,其中春旱、冬旱的干旱频率和等级总体较高。

【Objective】Drought is the most important abiotic stress facing agricultural management and economic development in many regions and countries.The aim of this paper is to identify the spatiotemporal variation of drought in Yunnan Province,using the standardized precipitation index(SPI).【Method】Meteorological data measured over the past 31 years from 36 meteorological stations across the province were used in the analysis.Multi-scale variations of the droughts in both time and space were calculated using SPI,GIS,nonparametric Mann-Kendall trend test and other methods.【Result】①Both annual and seasonal SPI fluctuated temporally,but we identified a small annual increase in spring SPI,small annual decreases in summer,autumn and winter SPI.The autumn SPI varied mostly,and the winter SPI least.The annual SPI varied from-1.95 to 1.44.②The annual drought frequency varied from 32.26%to 50.00%,with the severity of most droughts varying from mild to extreme range.Spatially,drought occurred more frequently in Wenshan,Honghe,Kunming,Chuxiong and Dehong than in other regions in the province.③Seasonally,drought frequency in spring,summer,autumn and winter was 39.86%,39.83%,38.43%,and 41.33%,respectively.Although drought frequency in different seasons was close,their severity differed considerably.④Annually,except for five meteorological stations which found increased drought frequency,drought frequency in other stations remained statistically the same.Seasonally,most stations showed decreased drought frequency in spring,eleven stations showed increased drought frequency in summer,and six and two stations showed increased autumn droughts and winter droughts,respectively.【Conclusion】Annual and seasonal drought frequency is spatially heterogeneous across the province.Droughts in the province are seasonal,with droughts occurring in spring and winter more frequently and severely.