基于SPEI指数分析1980-2019年漓江流域干旱特征

Research on Drought Characteristics in the Lijiang River Basin Based on Standardized Precipitation Evapotranspiration Index from 1980 to 2019

分析漓江流域1980-2019年的多时空尺度干旱特征变化,为漓江流域气象预警以及科学减灾等提供理论依据。基于漓江流域6个气象站点1980-2019年逐月降水与气温资料,计算不同时间尺度下的标准化降水蒸散指数,并结合Mann-Kendall检验法、Pettitt突变检验进一步研究干旱突变、干旱频率以及干旱的持续时间。结果表明:漓江流域干旱事件以轻旱和中旱为主,空间上灵川的干旱频率较高,时间上2015年是漓江流域干旱情况的一个突变点。不同时间尺度上,春秋两季逐渐干旱化,而夏季则相对湿润,冬季无明显变化趋势;月与年尺度的SPEI值变化较为平稳。剖析成因,春秋两季的降雨量逐年减少而均温逐年提升造成流域内趋于干旱化,但结合夏季气象资料,年尺度上的降雨与均温均是增长趋势,导致流域内总体上并无干旱趋势且以微弱的速率湿润化。

Analysis of the temporal and spatial scale drought characteristics variations in the Lijiang River Basin from 1980 to 2019,can provide a theoretical basis for meteorological warnings and scientific disaster reduction in the Lijiang River Basin.Monthly precipitation and temperature data from six meteorological stations in the Lijiang River Basin were utilized to calculate the Standardized Precipitation Evapotranspiration Index(SPEI)at different time scales,and the Mann-Kendall test and Pettitt mutation test were used to further study drought mutations,drought frequency,and drought duration.The results showed that the drought events in the Lijiang River Basin were mainly mild and moderate drought.Spatially,the drought frequency was higher in Lingchuan,and 2015 was a mutation point in the drought situation in the Lijiang River Basin.At different time scales,spring and autumn gradually became drought-prone,while summer was relatively humid,and there was no significant trend in the winter.The SPEI values at the monthly and annual scales varied relatively steadily.The analysis of the causes showed that the decreasing annual rainfall and increasing average temperature in spring and autumn caused the basin to tend towards drought,but combined with summer meteorological data,both rainfall and average temperature showed an increasing trend at the annual scale,resulting in no overall dry trend in the basin and a slight humidification at a slow rate.