Estimating 3-Dimensional Structure of Tropical Forests from Radar Interferometry / Estimativa da Estrutura 3-Dimensional das Florestas Tropicais Através de Interferometria de Radar

This paper describes the retrieval of 3-dimensional vegetation density profiles from interferometric synthetic aperture radar (InSAR) using physical models. InSAR’s sensitivity to vertical structure is generally regarded as less direct and more difficult to understand than that of lidar. But InSAR’s coverage is superior to that of lidar, suggesting InSAR is more promising as an important component of a global 3-dimensional forest monitoring technique. The goal of this paper is to introduce, simplify and demystify the use of simple physical models to understand InSAR. A general equation expressing the InSAR observation in terms of density is described heuristically, along with the approximations in its development. The information content of the equation leads to the estimation of density parameters. Preliminary results are shown from a multibaseline C-band (wavelength=0.056 m) vertical-polarization interferometer, realized with AirSAR flown at multiple altitudes over primary, secondary, and selectively logged tropical forests, as well as abandoned pastures at La Selva Biological Station in Costa Rica

Estimating 3-Dimensional Structure of Tropical Forests from Radar InterferometryEstimativa da Estrutura 3-Dimensional das Florestas Tropicais Através de Interferometria de Radar

This paper describes the retrieval of 3-dimensional vegetation density profiles from interferometric synthetic aperture radar (InSAR) using physical models. InSAR’s sensitivity to vertical structure is generally regarded as less direct and more difficult to understand than that of lidar. But InSAR’s coverage is superior to that of lidar, suggesting InSAR is more promising as an important component of a global 3-dimensional forest monitoring technique. The goal of this paper is to introduce, simplify and demystify the use of simple physical models to understand InSAR. A general equation expressing the InSAR observation in terms of density is described heuristically, along with the approximations in its development. The information content of the equation leads to the estimation of density parameters. Preliminary results are shown from a multibaseline C-band (wavelength=0.056 m) vertical-polarization interferometer, realized with AirSAR flown at multiple altitudes over primary, secondary, and selectively logged tropical forests, as well as abandoned pastures at La Selva Biological Station in Costa Rica.Resumo Este trabalho descreve o procedimento de recuperação do perfil tridimensional da densidade de vegetação, a partir de dados interferométricos de radar de abertura sintética (InSAR), utilizando modelos físicos. A sensibilidade da técnica InSAR para detectar estruturas verticais de vegetação é geralmente considerada menos direta e mais difícil de entender se comparado com dados de LIDAR (técnica utilizando laser). A utilização da técnica InSAR permite uma cobertura superior ao LIDAR e é potencialmente mais promissora como técnica de monitoramento global para a detecção da estrutura tri-dimensional de florestas. O objetivo deste trabalho é o de simplificar e desmistificar o uso de modelos físicos simples no entendimento da técnica InSAR. A equação geral que expressa a observação InSAR em termos de densidade é escrita heuristicamente, bem como as aproximações feitas no seu desenvolvimento. O conteúdo de informação da equação nos possibilita a estimação dos parâmetros de densidade da vegetação