四川盆地东部近50年降水与旱涝时间序列分析

利用四川盆地东部地区8个国家基准气象台站1960~2010年逐日降水观测资料，运用线性分析、降水趋势系数等方法，分析了四川盆地东部年降水量以及季节降水量的时间序列变化趋势。在此基础上，通过Z指数法建立旱涝指数模型，结合Mexican Hat小波变换理论研究旱涝灾害在不同时间尺度上的周期振荡和变化规律，并对未来旱涝演变趋势进行判断。结果表明，四川盆地东部地区年降水量有弱减少趋势，各季节降水趋势差异较大，秋季明显减少，而夏、冬季有增加趋势。各季节旱涝灾害变化存在着不同的年际、年代际周期变化特征，不同的时间尺度周期具有不同的交替变化规律。春、秋季节旱涝存在6 a和10 a左右周期振荡，近期6 a周期振荡显著。夏季现处于20 a左右尺度上降水稳定性较差的偏涝期内，易发级别高、灾情重的洪涝灾害。秋季近期仍处于10 a左右尺度周期的干旱期，并将逐步向下一个偏涝期过渡

ANALYSIS ON TEMPORAL SERIES OF PRECIPITATION AND DROUGHT-FLOOD ABOUT THE RECENT 50 YEARS IN THE EAST OF SICHUAN BASIN

Based on the daily precipitation data of eight representative stations in the east of Sichuan Basin during 1961-2010,this paper analyzed the variation tendency of the annual and seasonal precipitation by using linear analysis and precipitation trend coefficient method.And this paper defined regional flood-drought indices with Z-index and studied the periodic rules on multi-time scale by applying Mexican Hat wavelet transform method.The results indicated that annual precipitation had been lentamente declined in the area,but at the same time,the trends of seasonal precipitation was very different.The autumn precipitation was decreasing significantly,while there was an increasing trend in summer and winter.The flood-drought of four seasons had different annual and decadal time scale periodic variation characteristics,and different time scales had alternated on different cyclic rules.Approximate 6 years and 10 years periods in spring and autumn were found,and recently 6 years period was obvious.The summer had entered a water-logging period on approximately 20 years scale period and the precipitation was not stable.Thus,high grade and serious flood disaster was easy to occur.And recently,autumn is in a approximately 10 years scale drought period and will turn to a partial flood period in the future.