Using satellite scatterometers to monitor continental surfaces
Résumé
Scatterometers are sidelooking radar sensors designed to precisely evaluate the radar backscatter coefficient σ0 of the surfaces being observed. However, as we will aim to demonstrate, this high radiometric resolution is obtained at the cost of spatial resolution. Scatterometers are therefore radar sensors complementary to synthetic aperture radars (SAR). These promote spatial resolution at the cost of radiometric resolution. Thus, while current SAR are characterized by a spatial resolution of about 1 m, with a strong radiometric variation linked to the speckle effect, satellite scatterometers have a spatial resolution accurate to about 10 km, with an precision on the estimation of σ0 within a tenth of a decibel. Originally designed in order to evaluate the speed and direction of wind across ocean surfaces, the potential of these sensors for the monitoring of continental surfaces on a regional or global scale has been demonstrated.