MODIS数据湿地组分蒸散遥感模型

针对鄱阳湖地区湿度大且地表复杂多变的特点,从地表能量平衡出发,简化了陆-气相互作用的复杂过程,通过分析影响湿地蒸散的关键因子,建立了基于组分净辐射、组分土壤热通量、组分温度的湿地组分蒸散遥感模型.利用MODIS数据对鄱阳湖湿地的蒸散进行试验,根据TM分类图像得到了基于MODIS数据的1km各地类组分比率图像;在计算组分净辐射时,充分考虑到不同地表组分间对净辐射的作用差异,用组分比率、组分温度和组分反照率得到了各组分净辐射;在此基础上,得到了鄱阳湖湿地蒸散的分布.通过用余项法、实测数据和历史资料对新模型反演结果进行验证,结果表明,该模型能比较客观地反映鄱阳湖湿地蒸散分布状况.

Remote sensing model of component evapotranspiration in wetland using MODIS data

The study area "Poyang Lake area" is referred to humid environment and complex land coverage. In this paper, a component evapotranspiration model for wetland is developed based on component net radiance flux, component soil heat flux and component temperature through simplifying the complex processes of land-atmosphere interaction and analyzing vital factors which influence regional evapotranspiration. In the experiment the MODIS component proportion images with the 1km pixel are created according to TM classified images. Considering the difference of effect caused by different components on net radiance flux, the component net radiance flux is calculated using component proportion, component temperature and component albedo. The daily evapotranspiration distribution in Poyang Lake wetland is finally obtained. The new model is validated using residual method, field surveying data and history meteorological data. The result shows that the evapotranspiration acquired by the new model in Poyang Lake wetland is credible, and it can reflect the distribution of evapotranspiration in wetland objectively.