| The Yangtze River Estuary is located in the Chinese eastern coast with its own richnatural resources and key location, which turned into an important region ofinternational competition and economic development. Tidal flat is the sea-landimportant sediment zone that hands over, and is a kind of silty coastal wetlands betweenthe high waterside line at spring tide and the low water line neap tide which is affectedregularly by tidal action. It is a dynamic and unstable land and water resources; it is alsoan important object of resources and environment in the coastal zone. It has uniqueecological value and great resources potential. The soil water content of tidal flatdirectly or indirectly affects the own ecological environment. To monitor the soil watercontent which can be called soil moisture in the tidal flat has an important significance.Due to the special location of the tidal flat, the soil moisture measurement is moredifficult. Macro, synchronization, and low cost advantages of remote sensingtechnology, specially, synthetic aperture radar with high resolution, free from weatherand other advantages, using radar remote sensing to monitor soil moisture has beentaken more and more seriously.In this thesis, the Nanhui tidal flat in the Yangtze River estuary as study area, thetwo close time and HH polarized ENVISAT-ASAR images with different smallincidence angles for inversion were received on May2and3,2005, and the soilmoisture was calculated.(1) Choosing Gamma filter which can better get rid of the image speckle noise ofsynthetic aperture radar inherent structure to process ASAR images make sure theretention capacity of the smoothness and texture of the processed images.(2) Comparing the advantages and disadvantages of a variety of microwave remotesensing soil moisture inversion model, this study uses Zribi-Dechambre model based on the IEM model to calculate the soil roughness and soil moisture of Nanhui tidal flat.(3) On the basis of the data preprocessing, and then using Zribi-Dechambreinversion model calculate soil moisture of Nanhui tidal flat with the incidence anglenormalized. The results show that soil roughness mostly ranges from0.05cm~0.8cm andsoil moisture mainly distributes in the range of1%~3.8%. At last, the inversed results ofsoil moisture were validated by field measured data from Shanghai Geological SurveyAcademy. The RMSE is3.62%. This research provides an available and suitable methodwhich extracts soil moisture information by using synthetic aperture radar. |
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