2000-2017年锡林河流域地表蒸散量的时空特征及其影响因素

Spatio-temporal Characteristics of Evapotranspiration and Its Influencing Factors in Xilin River Basin from 2000 to 2017

揭示锡林河流域蒸散量的变化规律及其影响因素,为锡林河流域旱涝监测和水资源管理等提供科学依据。基于MOD16A2遥感产品,在实测数据验证的基础上,运用趋势分析和相关性分析等研究了2000-2017年锡林河流域蒸散量(以下简称ET)的变化规律及其影响因素。结果表明:年ET值具有较高的空间分异性,呈现出西北部低,东南部高的趋势;不同土地利用类型的年均ET由大到小依次为林地>耕地>未利用土地>草地>建设用地;ET与降水量和NDVI相关性最大,且呈正相关;ET变化随高程增加而增大,符合指数曲线变化特征;ET随着坡度的增加,先增大后减小,符合二次曲线变化特征;坡位表现为中坡的ET明显高于其他坡位,平坡的ET值最小。

The variation of evapotranspiration and its influencing factors in Xilin River Basin are revealed,which can provide scientific basis for drought and flood monitoring and water resources management in Xilin River Basin.Based on MOD16A2 remote sensing products and the verification of measured data,the change rule and influencing factors of ET in Xilin River Basin from 2000 to 2017 are studied by using trend analysis and correlation analysis,and the change characteristics of ET under different land use types are analyzed.The results show that the annual ET value has a high spatial differentiation,showing a low trend in the northwest and a high trend in the southeast;the annual average ET of different land use types is forest land>cultivated land>unused land>grassland>construction land.The correlation between ET and precipitation and NDVI is the greatest,with an average correlation coefficient of 0.65 and 0.72,respectively.In addition,topographic factors have a great influence on ET change,ET change increases with elevation,which accords with the characteristics of exponential curve change.ET increases first and then decreases with the increase in slope,which accords with the characteristics of quadratic curve change;while the ET of middle slope is obviously higher than that of other slopes,and the ET value of flat slope is the smallest.