基于SEBS模型的老哈河流域蒸散发研究

Evapotranspiration estimation in Laohahe Basin based on SEBS model

基于表面能量平衡系统(SEBS)模型,结合NOAA/AVHRR数据,估算半干旱的老哈河流域实际日蒸散发量,并将估算结果与结合FAO-Penman模型和作物系数法计算的参考作物蒸发量进行比较,最后综合分析了老哈河流域蒸散发与土地利用、归一化植被指数(NDVI)以及地表温度(LST)的关系。结果表明:SEBS模型在老哈河流域有较好的适用性;老哈河流域实际日蒸散发时空差异较大,其中7、8月份流域蒸散发量较大,9、10月份蒸散发量逐渐减小,流域西部山区的蒸散发量较大,中部和流域出口所在的平原区相对较小;流域不同土地利用类型蒸散发量不尽相同,其中林地的日平均蒸散发量最高,其次为耕地、灌丛和草地;流域实际蒸散发量与NDVI呈线性正相关,与LST呈线性负相关。

In this study,the ET in semi-arid Laohahe Basin was estimated based on the surface energy balance system（SEBS） model and NOAA/AVHRR data.The estimated results were then compared with the reference crop evapotranspiration computed combining the FAO-Penman model and crop coefficients.The relationship between the ET and the land cover,Normalized Difference Vegetation Index（NDVI） and Land Surface Temperature（LST） were comprehensively analyzed.The results show that the SEBS model has a good estimation of the ET for the Laohahe Basin.The ET shows a significant temporal and spatial variability.It gets higher values in July and August,and it demonstrates a descending trend in September and October.The ET is much larger in western mountains area than that in middle and eastern plain area.Different kind land covers have different ET values,in which the forest is the largest,and then in turns are cultivated land,thickets and grass.There exist a positive linear correlation between the ET and the NDVI,and a negative linear correlation between the ET and the LST.