On shape, orientation and structure of atmospheric cells inside wind rolls in SAR images

SAR images of sea surface often show roll-vortex structures, which have multiscale character. The present work investigates this aspect, using the two dimensional continuous wavelet transform (CWT2), which appears suitable to extract quantitative information about the structures present in SAR images. CWT2 analysis has been applied to ERS SAR images showing wind rolls, to evaluate the horizontal and vertical scales of the highest backscatter cells. The possibility to produce a SAR-like image at given scale lengths has permitted to evidence the backscatter cells. They have been characterised in terms of the orientation, size of their principal axes, area as well as of the spatial structure of the probability density function. The results may be used to study the inner structure of the atmospheric wind rolls