1960-2020年黄河流域气候干湿状况时空分异及变化趋势

Spatiotemporal Variation of Climate Dry-Wet Condition and Its Potential Trend in the Yellow River Basin from 1960 to 2020

基于湿润指数,利用黄河流域及周边1960-2020年113个气象站点日值气候数据,通过气候倾向率、Morlet小波、简单相关分析和Hurst指数等方法,分析近61a黄河流域干湿状况时空演变特征,预估黄河流域未来干湿变化趋势,以期为流域防旱减灾、合理利用气候资源提供科学依据。结果表明:(1)空间上,黄河流域年和季节湿润指数呈现为东南部高、西北部低。流域年、春秋两季以变干为主,湿润指数呈显著下降的站点占总站点的比例分别为5.31%、7.96%、6.19%;流域夏、冬季以变湿为主,湿润指数呈显著上升的站点占比分别为10.62%、13.27%。(2)年际变化上,1960-2020年黄河流域年和季节湿润指数均无显著变化趋势。流域全年、春、夏、秋、冬季分别处于半湿润、半干旱、半湿润、半湿润和半干旱状态。黄河流域年和季节湿润指数存在多时间尺度的周期振荡特征,第一主周期分别为3a、26a、14a、3a和15a。(3)降水量、相对湿度与湿润指数呈极显著正相关,日照时数与湿润指数呈极显著负相关,均为黄河流域湿润指数的主要驱动因素。(4)黄河流域年和季节湿润指数的Hurst指数均大于0.50,表明流域年、春季和秋季气候将持续变干,夏季和冬季气候将持续变湿。

Based on the humidity index, using the daily climate data of 113 meteorological stations in and adjacent the Yellow River Basin(YRB) from 1960 to 2020, climate trend rate, Morlet wavelet, simple correlation analysis, and Hurst index were used to analysis the spatiotemporal characteristics of dry-wet condition in the YRB in the latest 61 years and to predict the future trend of dry-wet changes in the YRB, to provide scientific basis for drought prevention and mitigation and rational utilization of climate resources in the YRB. The results showed that:(1)among all the geographic zones, the annual and seasonal humidity index in the YRB was high in the southeastern YRB and low in the northwestern YRB. Spatially, the climate of the annual, spring and autumn in the YRB was mainly dry, the proportions of stations with significant decrease of humidity index of the total stations were 5.31%,7.96% and 6.19%, respectively. The climate of summer and winter was mainly wet, the proportions of stations with significant increase of humidity index were 10.62% and 13.27%, respectively.(2) As for the interannual change, the annual and seasonal humidity index of the YRB from 1960 to 2020 showed no significant change. Semi-humid,semi-drought, semi-humid, semi-humid, semi-drought were found in entire year, spring, summer, autumn, and winter,respectively. The annual and seasonal humidity index of the YRB had periodic oscillation characteristics at multiple time scales, and the first main period was 3 years, 26 years, 14 years, 3 years and 15 years, respectively.(3) The change of humidity index in the YRB was extremely significantly positively correlated with precipitation and relative humidity. There was a extremely significant negative correlation between sunshine duration and humidity index. Precipitation, relative humidity, and sunshine duration were the main factors affecting the change of humidity index in the YRB.(4) The Hurst index of annual and seasonal humidity index in the YRB were larger than 0.50,indicating that the climate of annual, spring, and autumn of the YRB would continue to be drying, the summer and winter climate would continue to be wetting.