基于多尺度SPI的广西干湿特征与未来趋势

Analysis on Meteorological Arid-Wet Characteristics and Its Future Trend in Guangxi Based on Multi-scale SPI

针对多年来广西旱涝并存、灾害频繁的现象,基于高时空分辨率的APHRODITE和TRMM 3B42V7逐日降雨数据,采用标准化降水指数(SPI)和R/S方法分析了1951—2015年广西地区年、季、月多个时间尺度下,气象干湿演变的频率、影响范围、强度及未来趋势的综合特征。结果表明:(1)月尺度能更好地反映广西干湿的频繁交替现象,而年、季尺度能更好地反映广西干湿转化的周期性特征。(2)广西不同时间尺度干湿的频率、影响范围、强度特征差异显著;其中4月、8月干湿最为严重,其干湿频率大于40%、区域性及以上范围干湿事件年数超过27a,中度及以上强度的干湿事件年数超过40a。(3)未来一段时期,广西春季、秋季、4月、8月和10月湿润总体呈减弱趋势,干旱总体呈增强趋势;其他季节、月份广西干湿演变的强弱趋势不显著。综上,月尺度在反映广西短期干湿事件及其转化规律方面比年、季尺度有更好的指示作用,进一步明晰月、乃至更精细时间尺度下广西旱涝演变特征,将为提高区域旱涝预警能力、制定减灾应对策略、调控灾损风险方面奠定科学基础。

Aiming at the frequent disasters of droughts-floods and its coexistence in Guangxi over the years,the meteorological arid-wet characteristics and its future trend were analyzed by using standardized precipitation index（SPI）and R/S method during the period from 1951 to 2015,which involved the frequency,scope of influence and intensity of regional arid-wet,based on the high temporal-spatial daily precipitation datasets of APHRODITE and TRMM 3 B42 V7.The results showed that：（1）the SPI of monthly scale could better reflect the sharp turn of arid-wet,while the SPI of annual or seasonal scales could better reflect its periodic features in Guangxi;（2）there were significant differences of arid-wet characteristics on the frequency,scope of influence and intensity in different temporal scales;especially,the intense arid-wet events primarily occurred in April and August,with its frequency events more than 40%,its regional or larger influence events more than 27 years and its medium or stronger intensity events more than 40 years;（3）in the near future period in Guangxi,the meteorological wet events will present weakening trend and the meteorological arid events appear strengthening trend,mainly exist in spring,autumn,April,August and October.There are no significant stronger or weaken trends in the other temporal scales or periods.In conclusion,the monthly scale has a better indicative function than the annual or seasonal scales in reflecting short-term aridwet events and its transformation.Therefore,the drought and flood evolution of Guangxi is urgently explored on monthly scale or shorter temporal scales,which can lay the foundation for improving the ability ofdrought-flood warning,generating the disaster mitigation strategies and regulating the risk of disaster losses.