Evaluation of the influence of land cover on the noise level of ERS-scatterometer backscatter

In this study we assess the impact of different land cover types on the azimuthal noise of backscatter signal using multi-year ERS-scatterometer data. Results indicate a strong response of the azimuthal noise level to the different land cover types like rainforests, lakes, rivers, floodplains, coastal areas, permanent snow or ice, urban areas, and deserts as well as topography. Complex topography with high standard deviation in heights, ridge-shaped features oblique to the satellite track on the surface, and water-contaminated areas are the main causes of the high azimuthal noise in scatterometer measurements. The azimuthal noise fluctuations generally show a minimum over rain forests and maximum over sand deserts. Changes in the level of azimuthal noise of backscatter signal clearly reflect changes in land cover or surface roughness.