Abstract
The advantage of implementing the Water Cloud Model (WCM) is in being able to express complex scattering characteristics in a vegetated area with simple bulk vegetation descriptors. However, there has been a lack of understanding or consensus about the optimal set of vegetation descriptors. In this paper, the original and improved expressions of WCM are evaluated and the optimal vegetation descriptors are presented by examining the relationship between WCM vegetation parameters and the theoretical scattering model predictions. In addition, the condition-specific regression relationship between bulk vegetation descriptors and theoretical scattering and attenuation coefficients, expressed by the A and B parameters in the WCM, is analyzed in relation to the shape, size, and orientation distribution of the scatterer. Furthermore, the influence of radar observation conditions on the parameterization of the WCM is presented. The results show that the particle moisture content and the vegetation water content can be the optimal vegetation descriptors, denoted by the V 1 and V 2 variables in the WCM, respectively.
Highlights
Due to its all-weather imaging and vegetation penetration capabilities, remote sensing of vegetated areas with Synthetic Aperture Radar (SAR) has a great potential for retrieving bio- and geo-physical parameters related to vegetation and the underlying soil surface
The total backscatter can be obtained by an incoherent sum of several scattering contributions, including direct backscattering from the vegetation layer, direct backscattering from the underlying rough surface, scattering interaction between the vegetation and the ground surface, and ground–vegetation–ground multiple bounce
There have been few studies on the selection of the optimal vegetation descriptors in the Water Cloud Model (WCM). Another problem in the parameterization of the WCM is that two unknown model parameters, which relate vegetation descriptors to microwave scattering and attenuation in the canopy layer, have to be determined prior to performing inversion
Summary
Due to its all-weather imaging and vegetation penetration capabilities, remote sensing of vegetated areas with Synthetic Aperture Radar (SAR) has a great potential for retrieving bio- and geo-physical parameters related to vegetation and the underlying soil surface. In order to estimate physical properties of scatterers from SAR data, it is necessary to investigate different scattering contributions among total backscattered signals by modeling the interactions of microwaves in the vegetated areas. The theoretical scattering models have been used successfully to interpret scattering characteristics of vegetated areas and to predict radar signals in relation to the biophysical properties of plants They are usually complex and inconvenient because of a large number of input parameters which lead to complexity in resolving the inverse problem. There have been few studies on the selection of the optimal vegetation descriptors in the WCM Another problem in the parameterization of the WCM is that two unknown model parameters, which relate vegetation descriptors to microwave scattering and attenuation in the canopy layer, have to be determined prior to performing inversion. The sensitivity of WCM parameters to observation conditions is discussed concludes this paper in Sections 4 and 5
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
