Observing the snow and ice properties over the Labrador shelf with helicopter-borne Ground-Penetrating Radar, Laser and Electromagnetic sensors

During March 2009, a unique data set was collected with helicopter-borne sensors from the Labrador shelf. For the first time a Ground-Penetrating-Radar (GPR) provided snow thicknesses and complemented the Electromagnetic-Laser (EM) and Video-Laser data sets to explain the ice and snow properties of the land-fast and mobile ice covers. Ice and snow thickness data were collected with helicopter-borne EM and GPR sensors along shoreward flight paths and video data with a video-laser system along seaward flight paths. A total of 550km of ice and snow thickness profile data was collected and a total of 550km of video data. As indicated by the RADARSAT-2 image, four distinct ice thickness regimes were seen. Offshore, small wave-broken floes existed with a very homogeneous 1.2m modal thickness. Inshore of this region, large floes were observed with the same modal thickness of 1.2m but having a larger thickness variability. Areas of open water and thin ice were seen offshore of the rough outer region of the land-fast ice. The GPR data showed that offshore the snow thickness appeared thinner as snow was continually blown from the ice into leads between the floes where it stimulated the formation of frazil ice.