Estimating surface soil moisture and soil roughness over semiarid areas from the use of the copolarization ratio

This paper presents a new method to retrieve soil moisture and roughness fr om ERS-1. Wind scatterometer (WSC) data measured over the HAPEX-Sahel area (semiarid environment). The retrieval algorithm makes full use of the multi angular acquisitions and the high temporal repetition of the measured backs cattering coefficients. The vegetation contribution to the signal is taken into account through a first-order radiative transfer model. The soil moist ure and roughness are subsequently retrieved, throughout the rainy season, using the copolarization ratio as expressed by Oh et al. [IEEE Transactions on Geoscience and Remote Sensing GE-30 (1992) 370-381.]. The paper describ es the data and the approach used, together with the results gained. A good sensitivity of the backscattering coefficient to soil moisture is obtained . The results are compared with data collected during the HAPEX-Sahel campa ign. (C) 2001 Elsevier Science Inc. All rights reserved.