甘肃省气象干旱的多尺度时空变化综合分析

Multi-scale Temporal and Spatial Variation Comprehensive Analysis of Meteorological Drought in Gansu Province

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 theory and decision-making basis for drought resisting and calamity reduction in Gansu Province,spatial and temporal patterns including intensity,frequency,spatial distribution and periodic feature are investigated by using the standardized precipitation index（SPI） based on the monthly precipitation from meteorological data of 52 stations during the period of 1951-2010.The results show that the performance of the standardized precipitation index（SPI） in different time scales in describing drought are different;the intensity and frequency of drought appear regular spatial and temporal patterns,and drought and flood appear inter-decadal variability significantly;the frequency of medium drought distributes between 26% and 60%,and the extreme drought frequency is in the range of 2.01% and 18.00%;drought intensity in dry season and wet season appear downward trend;the SPI varies with a primary period of 13a;Gansu Province suffers a gradual decreasing trend of drought from northwest to southeast spatially,and some local wet areas tend to be drought.