Speckle Noise Pedestal In The Spectra Of SAR Imagery Of The Ocean

The shape of the speckle noise pedestal inherent to the spectra of synthetic aperture radar (SAR) imagery of the ocean is being analyzed on the basis of Canadian satellite RADARSAT-2 data as well as with numerical modeling. It was shown that in centrally symmetric SAR image spectra the pedestal is on average close to an elliptical cone with a slightly smoothed apex at the origin and a base with semi-axes lengths inversely proportional to nominal sizes of SAR resolution cell. This shape is retained both for longitudinal and transverse probing with respect to the direction ocean wave propagation. With increasing ocean wave intensity, the height of the speckle noise cone increases and, thus, the speckle noise energy is mostly concentrated in the low frequency region of the image spectrum, i.e. in the field of large ocean waves.