| タイトル | A First-Order Radiative Transfer Model for Microwave Radiometry of Forest Canopies at L-Band |
| 著者（英） | Kurum, Mehmet; Lang, Roger H.; Jackson, Thomas J.; Joseph, Alicia T.; O'Neill, Peggy E.; Cosh, Michael H. |
| 著者所属（英） | NASA Goddard Space Flight Center |
| 発行日 | 2010-01-01 |
| 言語 | eng |
| 内容記述 | In this study, a new first-order radiative transfer (RT) model is developed to more accurately account for vegetation canopy scattering by modifying the basic r-co model (the zero-order RT solution). In order to optimally utilize microwave radiometric data in soil moisture (SM) retrievals over moderately to densely vegetated landscapes, a quantitative understanding of the relationship between scattering mechanisms within vegetation canopies and the microwave brightness temperature is desirable. A first-order RT model is used to investigate this relationship and to perform a physical analysis of the scattered and emitted radiation from vegetated terrain. The new model is based on an iterative solution (successive orders of scattering) of the RT equations up to the first order. This formulation adds a new scattering term to the i-w model. The additional term represents emission by particles (vegetation components) in the vegetation layer and emission by the ground that is scattered once by particles in the layer. The new model is tested against 1.4 GHz brightness temperature measurements acquired over deciduous trees by a truck-mounted microwave instrument system called ComRAD in 2007. The model predictions are in good agreement with the data and they give quantitative understanding for the influence of first-order scattering within the canopy on the brightness temperature. The model results show that the scattering term is significant for trees and modifications are necessary to the T-w model when applied to dense vegetation. Numerical simulations also indicate that the scattering term has a negligible dependence on SM and is mainly a function of the angle and polarization of the microwave observation. |
| NASA分類 | Earth Resources and Remote Sensing |
| 権利 | Copyright |
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