Combined use of spectral measurements: a promise for surface parameter retrieval

The objective of this study is to underline the benefits of a combined use of different spectral measurements and models in the retrieval of surface parameters controlling the hydrological cycle. The authors developed a method aimed at integrating data from various satellites, in different spectral bands (visible, thermal infrared and microwave) along with models adapted to each band in a two step iterative optimization procedure. They first invert radiative transfer model in the visible to retrieve a set of surface parameters from AVHRR visible and near-infrared reflectances. In a second step, these parameters in conjunction with surface temperature derived from AVHRR lire used as input into a radiative transfer model in the microwave region to simulate brightness temperature in SSM/I 19.35 and 37 GHz channels. By minimizing the difference between observed and simulated brightness temperatures, a set of relationship between surface albedo and soil moisture, surface reflectance and vegetation water content are discussed