Abstract
Bipolarized microwave brightness temperatures of central Spain are analysed at two frequencies (19.35 and 37 GHz) together with infrared (IR) radiances. The satellite data were obtained for the June 1991 period, in the framework of the EFEDA campaign (European Field Experiment in a Desertification‐threatened Area, Bolle et al., 1993). The microwave data are from the DMSP Special Sensor Microwave/Imager (SSM/I). The IR surface temperatures and emissivities are derived from NOAA/AVHRR (channels 3, 4, 5) and METEOSAT (IR channel) radiances. Atmospheric corrections are performed using the French weather forecast model outputs. A method is proposed to perform the temporal extrapolation of the AVHRR‐derived surface temperature with METEOSAT. An estimation of the surface temperature of homogeneous SSM/I's pixels is obtained from METEOSAT. The problem with retrieving geophysical parameters from SSM/I (i.e. canopy structure parameters, surface temperature and near‐surface soil moisture) is then addressed by applying methods which were finalized from a field experiment (Calvet et al., 1995a). The vegetation microwave emission is analysed using a random continuous approach. Finally, the surface temperatures obtained from SSM/I in dry conditions are compared with the IR‐derived ones.
