Nearshore ice surface roughness surveys on Lake Superior

Nearshore ice surface roughness and snow thickness were surveyed with an autolevel on Lake Superior for application to multisensor satellite remote sensing of Great Lakes ice cover. Topographic transects across four commonly occurring ice facies were measured with 0.2 cm vertical and 5.0 cm horizontal resolutions. The four ice facies rank in roughness as follows (RMS roughness (cm)/correlation length (cm) in parentheses): single large pressure ridge (30/125), series of small pressure ridges (16/110), ball ice zone (8/70) and young ice cakes (5/145). Thin snow cover was widespread on the nearshore facies, with potential for generating diurnally-varying melt related changes in electromagnetic signatures during spring warming.