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为给甘肃省抗旱减灾提供理论和决策依据,选取甘肃省境内的52个气象台站1951～2010年的月降水数据,基于标准化降水指数(SPI),采用干旱强度分析、干旱频率分析及小波分析等方法对不同时间尺度的气象干旱强度、频率、空间分布、周期分析等时空变化特征进行了研究。结果表明,不同时间尺度的SPI对干旱表征效果有差异;干旱频率和强度呈规律性的时空变化,年代际变化呈现大旱大涝的特征;中旱以上频率分布在26%～60%之间,极端干旱以上频率分布在2.01%～18.00%之间;雨季和旱季干旱强度均呈现下降趋势;干旱以13年为主周期变化;全省旱情分布呈现出从西北地区向东南地区逐渐减弱的趋势,局部湿润地区有变旱的趋势。
In order to provide theoretical and decision-making basis for drought relief in Gansu Province, monthly precipitation data of 52 meteorological stations in Gansu Province from 1951 to 2010 were selected. Based on the standardized precipitation index (SPI), drought intensity analysis, drought frequency analysis and wavelet analysis Methods The spatial and temporal variations of meteorological drought intensity, frequency, spatial distribution and periodical analysis at different time scales were studied. The results showed that SPI had different effects on drought characterization at different time scales. The frequency and intensity of drought had a regular spatial and temporal variation, and the interdecadal variation was characterized by drought and floods. The frequency distributions were above 26% ~ 60% , The frequency distribution above extreme drought was between 2.01% ~ 18.00%; the drought intensity in both rainy season and dry season showed a downward trend; the drought changed mainly in 13 years; the drought distribution in the whole province showed a gradual trend from northwest to southeast , Humid areas have the tendency of drought.