基于IDL的MODIS影像地表蒸散发参数反演系统

Inversion system of surface evapotranspiration parameters for MODIS data based on IDL

针对水文水资源分析计算所需要的地表蒸散发参数难以获取的问题,利用MODIS遥感影像数据和气象观测数据,采用SEBAL(地表能量平衡)模型,并结合ENVI/IDL二次开发语言构建了流域陆面蒸散发反演系统.以黄河三花间(三门峡一花园口区间)流域为例,编程实现了地表温度、植被指数、水体指数、不透水面指数等蒸散发计算所需相关地表参数的提取和日陆面蒸散发量的计算,并利用IDL的统计分析功能,通过随机采样,综合分析了地表参数与蒸散发量的关系.应用结果表明,该系统具有平台无关性特点,人机交互友好,可作为独立模块加入水文分析等专业系统,有效解决了通用遥感软件缺乏专业信息提取功能的问题.

As for the difficult acquisition of surface evapotranspiration parameters for analysis and calculation of hydrology and water resources,an inversion system of surface evapotranspiration for watersheds was establihed by using the MODIS data and observed meteorological data and the SEBAL model based on ENVI/IDL. The Sanmenxia-Huayuankou watershed of Yellow River was taken as a case study. The relevant surface parameters for calculating evapotranspiration were extracted and realized,including surface temperature,vegetation index,water index,impervious surface index and so on. The daily evapotranspiration was then calculated. The relationship between the surface parameters and the evapotranspiration was comprehensively analyzed by the statistical analysis function of IDL through random samples. The results show that the system is independent of software and has friendly man-machine interaction. It can be embedded into professional hydrological analysis systems as the independent module,and it effectively solves the problem of extracting professional information that general remote sensing software can not be achieved.