基于Landsat 5 TM的祁连山区蒸散发遥感估算——以青海祁连县为例

Study of Evapotranspiration in Qilian Mountains Based on Landsat-5 TM——A case of Qilian County Qinghai Province

蒸散发的估算在区域能量平衡和水分循环研究中具有重要意义.本研究利用Landsat 5TM数据和能量平衡模型相结合,通过遥感数据获取各参量,对祁连山区的日蒸散发进行估算,研究表明估算值与实测值基本一致,相对误差为4.23%,基本上满足了该区域蒸散发研究的精度要求.通过对蒸散结果的分析发现,该区域的日蒸散发空间分布受气候特征、地形因素、土壤供水条件及土地利用类型的影响比较严重,其分布趋势主要在空间上表现出随海拔的降低而降低,阳坡蒸散量大于阴坡,在土地利用类型上呈现按照"林地>沼泽地>水域>草地>耕地>城乡工矿居民用地"的类型而降低的规律,而永久性冰川雪地以及裸土裸岩石砾地的蒸散发则随冰川面积的缩小而减小.

The estimation of evaporation in regional energy balance and water cycle research is of great significance.In this study,we simulated the daily evapotranspiration of the Qilian Mountains by the TM,SEBAL model and various parameters obtained through remote sensing data,found that the estimates consistent with the measured values,the relative error is 4.23%,basically meet the regional evapotranspiration of accuracy.Throughanalysis of the results found that the region spatial distributionof evapotranspiration seriously affected bythe climate characteristics,terrain,the water supply conditions of soilandthelanduse types.In space,the distribution trend is mainly demonstrated decreases with decreasing with altitude,sunny slope＇s evapotranspiration greater than shady slope＇s;and in land use types,present on land use types in accordance with the＂forest land 〉water areathe〉 marsh grasscultivated landland for urban and rural residents of industrial＂type of law,and the permanent glaciers and snow and bare soil bare rock is fertile land evaporation decreases with glacier area reduction.