近59 a锡林河流域潜在蒸散发及地表干湿状况变化趋势分析

利用1960—2018年锡林河流域周边13个气象站的逐日气象资料,采用世界粮农组织(Food and Agriculture Organization of the United Nations,FAO)推荐的Penman-Monteith公式计算各气象站多年潜在蒸散发量及相对湿润度指数。通过利用主成分分析、相关分析和偏相关分析,探讨了锡林河流域潜在蒸散发、地表干湿状况多年变化规律;分析了影响潜在蒸散发的主要气象因子及各气象要素间的相互作用;着重讨论了锡林河流域潜在蒸散发的周期变化及其与相对湿润度指数、各气象要素的相互作用。结果表明:流域近59 a潜在蒸散发整体呈现增长趋势,且上升趋势显著,存在显著增加—减小交替的多尺度时频变化特征和多主周期变化规律;各气象要素中潜在蒸散发对温度的响应较大,平均风速次之;平均相对湿度受到潜在蒸散发的影响较大,降水次之。整个流域环境有不显著的变湿润趋势。

Trends of potential evapotranspiration and surface wet conditions in the Xilin River Basin in recent 59 years

Using the daily meteorological data of the period from 1960 to 2018, which were obtained from 13 meteorological stations surrounding the Xilin River Basin,Inner Mongolia,China,the Penman-Monteith formula recommended by the Food and Agriculture Organization of the United Nations （FAO） was used to calculate the multiyear potential evapotranspiration and relative humidity index in each weather station. The potential evapotranspiration and surface wet and dry conditions of the Xilin River Basin were explored over the aforementioned period through principal component,correlation,and partial correlation analyses. The cyclical changes in the potential evapotranspiration in the Xilin River Basin and their correlations to the relative humidity index and various meteorological elements were discussed. The results indicated that the potential evapotranspiration in the basin in recent 59 a exhibited a significant overall increasing trend. Significant increasing and decreasing trends were found among the characteristics of the multiscale time-frequency changes and multiperiod changes,respectively. The response was larger,followed by average wind speed. The average relative humidity followed by precipitation were the most affected by the potential evapotranspiration. The entire basin environment exhibited an insignificant tendency to become humid.