Soil moisture retrieval from co-polarized ALOS PALSAR backscattering in the Zwalm and Alzette catchments
Hans Lievens(1), Hilde Vernieuwe(1), Niko Verhoest(1), Valentijn Pauwels(1), Bernard De Baets(1), Patrick Matgen(2), Mara Montanari(2), Lucien Hoffmann(2) and Francesco Mattia(3)
(1) Ghent University, Coupure links 653, 9000 Ghent, Belgium
(2) Centre de Recherche Public - Gabriel Lippmann, Rue du Brill 41, L-4422 Belvaux, Luxembourg
(3) Consiglio Nazionale delle Ricerche, Via Amendola 122/D, I-70126 Bari, Italy
It is well known that Synthetic Aperture Radar (SAR) sensors have a large potential for observing soil moisture. However, the sensitivity of L-band sensors to real world soil moisture data has not been discussed to a large extent. In current paper, different agricultural fields in the Zwalm catchment (Belgium) and the Alzette basin (Luxemburg) have been selected to investigate the potential of PALSAR co-polarized imagery for monitoring soil moisture data. Both sites have been extensively sampled with respect to soil moisture, soil roughness, and vegetation parameters during several field campaigns. Various state-of-the-art backscatter models, including the Integral Equation Model (IEM), and the models of Dubois et al. and Oh et al., are inverted, and the difference in soil moisture estimation due to the different retrieval algorithms is analyzed. Furthermore, the accuracy of soil moisture retrieval with respect to uncertainty in soil roughness characterization is assessed. Based on analysis results, recommendations for soil moisture retrieval from co-polarized ALOS PALSAR data are given.