|
Abstract
|
|
|---|---|
| One of the main strengths of active microwave remote sensing, in relation to frequency, is its capacity to penetrate vegetation canopies, and reach the ground surface, so that information about the vegetation and hydrological properties of the surface can be drawn. All this information is gathered in the so called backscattering coe?cient (?0), and in a vegetated medium, this coe?cient reveals important information on the vegetation water content, geometry and/or structure of the canopy elements, above ground biomass, and soil roughness and moisture. In the scope of microwave frequencies, modeling the backscattering coe?cient of vegetated terrain, involves taking into account scattering models that simulate the soil surface contribution by means of its physical variables, and the vegetation layer, through the knowledge of its biophysical properties. Soil surface scattering models require describing parameters of roughness, like soil pro?le height displacement standard deviation and correlation length, and moisture, which determines surface re ective properties. The knowledge of these parameters, allows to establishing surface scattering models with di?erent validity ranges. Some frequently used models are divided into theoretical and empirical models. The vegetation canopy is usually regarded as a homogeneous, or random layer, at a certain height above terrain surface, and it is used to compute the attenuation through this layer. This requires a geometric generalization of the vegetation layer and its constituents, specifying additionally its electromagnetic properties. The main simulation models are based on Radiative Transfer theory, which allows for di?erent approaches and simpli?cations. In this sense, somo of these models, can be e?ciently adapted to any vegetated medium, and the constituents can by approximated by more general variables like Leaf Area Index (LAI), or Water total Content (WTC) of Vegetation. Moreover, in the microwave region, it is also possible to relate radar measurements to the above ground biomass. | |
|
International
|
Si |
|
Congress
|
38th (Comittee on Space Research) COSPAR Scienti?c Assembly 2010 |
|
|
960 |
|
Place
|
Bremen |
|
Reviewers
|
No |
|
ISBN/ISSN
|
|
|
|
|
|
Start Date
|
18/07/2010 |
|
End Date
|
25/07/2010 |
|
From page
|
|
|
To page
|
|
|
|
|