Wind-induced directional anisotropy of microwave backscatter and its impact on imaging of the Antarctic continental snow cover

The 500 km wide swath of the right-looking ERS wind scatterometer and the orbital geometry allows measurement of the microwave backscatter of the entire Antarctic region north of latitude 79/spl deg/S. The values of the backscatter coefficient depend on the incidence angle and look directions of the antenna beams. Models of microwave backscatter which omit the azimuthal modulation introduce significant biases and temporal variations into the isotropic component of the backscatter. Use of these models, therefore, is likely to mask real physical variations due to changing surface conditions in areas where directional anisotropy is significant.