Low Back-scattering Bands Paralleling Pressure Ridges on First Year Sea-Ice

Sea ice roughness characteristics are important parameters of climate and ocean circulation models. Pressure ridges are large features which size, orientation and density have a major impact on heat and momentum fluxes. Extraction of these information from satellite images is a necessary step since it could allow to introduce these parameter´s variability into models. In this paper we explore the occurrence of linear structures of low back-scattering which had previously been observed alongside pressure ridges on satellite images recorded late at spring. Measurements described in this research paper were carried out offshore of Kuujjuarapik on the East coast of the Hudson Bay. The ice sheet is composed of a first year ice ranging from lm25 to lm55 in thickness. Data were collected from mid-April to mid-May which covers the melt initiation period for this region of the bay. Measurement sites were chosen to sample a range of ridge orientations relative to the SAR incident beam. Selection criteria were set to get ridges that display homogeneity of the snow field along their axis. Data from 4 field works are presented. We show a correlation between low return bands and snow structure slopes that develop downwind of pressure ridges. Also, we discuss the impact of the snow wetness content on image resolution.