Pressure ridges extraction usign Radarsat fine beam model

摘要

We present data recorded before and duirng the spring melt onset. This time period was chosen due to the fast evolution of snow and ice characteristics and, therefore, of the contrast between ice plate and ridges. With the development of a wet film on the snow and ice surface, reflection on some ice blocks enhances the ridge return while due to the increased forward scattering, the signal intensity from flat ice areas is reduced. As the melt goes on, this produces an iamge on which the ridge-plate contrast allows the extraction of a larger proportion of hte ridge network. This data was then used to position ridges on an image recorded before the melt and compute ridge statistics. We show that ridges are not only characterized by bright linear structures. The bright structure is paralleled by a black structure in which the return is lower than the background. This explains why standard resolution images do not give good resutls in ridge detection. Pixels from both structures are itnegrated, producing an iamge with a reduced ridge-plate contrast.