用Z指数作为旱涝等级标准, 利用重庆城区百余年降水量资料, 分析了历年及四季旱涝出现的频率, 采用趋势分析、最大熵谱分析以及小波分析方法, 研究了重庆城区年及四季旱涝的变化特征。结果表明:重庆城区年及四季干旱和洪涝发生频率均在25%以上, 重庆旱涝灾害较频繁; 多项式拟合和周期分析表明, 城区年及四季旱涝具有阶段性变化特征, 某些阶段年际变化特征也很显著, 总体而言, 年及夏季旱涝的年代际变化特征较明显, 其它三个季节则是年际变化特征较明显。近几年的年旱涝变化处于偏涝阶段; 而近几年夏季的旱涝变化, 从年代际尺度来看, 目前处在偏旱阶段, 出现干旱的可能性较大; 而其它三季则处于偏涝阶段。
Using Z index as classification of drought-flood intensity and based on the precipitation data in Chongqing urban in the past 100 years, the frequencies of years and four seasons of flood-drought have been analyzed and their change features have also been studied based on tendency analysis and MESA and wavelet ways. Results show that the frequencies of flood-drought of years and four seasons exceed 25% in Chongqing urban and flood-drought disasters are high frequency. The varieties of flood-drought contain staggered features and the characteristics of interannual variability are obvious in some period of time using the polynomial fitting and MESA ways. In a word, the features of interdecadal variability are in evidence in year and summer but those of interannual variability are obvious in other three seasons. The signals with different scales have stronger local features in time-frequency distributing in Chongqing urban in year and four seasons. Their phases are difference with different scales and they are more complex while the scales are small. The variety features of flood-drought indexes in year locate flood phase with both large and small scales, but they locate drought phase in summer in recent years. The probability of drought disaster is high frequency in summer but that of flood disaster in other three seasons during the future period of time.
重庆市科技攻关项目"重庆市旱涝灾害监测预警决策服务系统研究"(2006AC7053); 重庆市科技合作项目"重庆市冷暖旱涝灾害变化及其影响研究"(2004-8770); 重庆市气象局开放式研究基金课题"重庆市主城区气候变化及城市化气候效应的初步分析"共同资助
李永华, 高阳华, 唐云辉. 重庆城区近百余年旱涝变化[J]. 高原气象, 2008, 27(1): 162-168.
LI Yong-hua, GAO Yang-hua, TANG Yun-hui. The Changes of Flood-Drought in Chongqing Urban Area during the Past 100 Years. PLATEAU METEOROLOGY, 2008, 27(1): 162-168.
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