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sur le développement des zones arides et semi-arides

Titre : Parametrización y optimización de modelos de inversión para la obtención de humedad del suelo a partir de datos satelitales de Radares de Apertura Sintética

Parameterization and optimization of inversion models for soil moisture retrieval from Synthetic Aperture Radar (SAR) data

Auteur : Barber, Matías Ernesto

Université de soutenance : Universidad de Buenos Aires

Grade : Doctor Ciencias Físicas 2013

Résumé
Within the framework of the Argentinean Space Plan (PEN), the National Space Activities Commission (CONAE) plans to launch the SAOCOM mission, which involves a synthetic aperture radar (SAR) operating in the microwave region (λ = 23cm) and whose main goal is the estimation of soil moisture over the Pampas Plains. Estimation of biogeophysical variables through radar images is an ill-posed problem, where there are often many combinations of surface parameters that produce the same SAR observations. For this reason, there are various retrieval techniques, which should take into account 1. the difficulty of parameterizing the scattering models which govern the response of the target to an electromagnetic wave impinging on it, 2. uncertainties in the radar measurement due to speckle noise, 3. instrumental noise from the sensor, 4. uncertainties from the spatial variability of the target variables, in particular of soil moisture. In this thesis a Bayesian retrieval scheme was developed, which takes into account all these issues. This scheme is assessed with SAR data and field measurements from various campaigns involving airborne and satellite systems. Also, the Bayesian scheme considers all the difficulties encountered in the development of an operational soil moisture product and can lead to an alternative algorithm to that developed by CONAE for the SAOCOM mission.

Mots clés : HUMEDAD DEL SUELO ; RADAR DE APERTURA SINTETICA ; METODO BAYESIANO DE INVERSION ; ESTIMADORES BAYESIANOS ; RUGOSIDAD EN SUPERFICIES AGRICOLAS ; TELEDETECCION EN MICROONDAS ; SOIL MOISTURE ; SYNTHETIC APERTURE RADAR ; BAYESIAN RETRIEVAL SCHEME ; BAYESIAN ESTIMATES ; AGRICULTURAL SOIL ROUGHNESS ; MICROWAVE REMOTE SENSING

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