Validating and improving satellite measurements of sea ice thickness and surface roughness using an airborne ice thickness sensor system.

The areal extent and thickness of Arctic sea ice is declining at an accelerating rate, faster than forecast by global climate models. Sea ice is an important indicator of climate change, a habitat for whales, seals, and polar bears, and is important the l ives of indigenous populations around the Arctic for travel and hunting in the winter. The ice is a hazard to Arctic marine activities such as shipping and resource extraction. Both Canada and Norway have a vested interest in the Arctic Ocean and its sea ice cover. In 2010, collaborative research was undertaken by the Norwegian Polar Institute (NPI) and the University of Alberta (UoA). Airborne surveys of sea ice thickness and surface properties over large regions were combined with in-situ measurements for the validation of new satellite sensors such as Cryosat-2. Cryosat-2 aims to measure changes in the thickness of the sea ice by measuring the height of the ice surface above the water, called freeboard, and assuming a snow depth, snow density and ice density. Uncertainty in these properties and thus the freeboard to thickness ratio require that the estimates of Cryosat-2 be validated and calibrated in order to provide accurate results to the data user. The HEM sensor utilized by NPI and the UoA direct ly measures the distance to the ice surface and to the ice bottom and is not dependent on ice or snow density. Studies have shown that the HEM sensor is very accurate. The objectives of this project are to utilize the data collected in 2010 to: 1.Analyz e laser scanner and altimeter results for variability in the sea ice freeboard to ice thickness ratio, sea ice surface roughness and ridge properties. 2.Collect new EM-bird and in-situ measurements to retrieve melt pond information from the airborne lase r scanner system. It is expected that project will provide new data for the validation of satellite data,and new sea ice thickness, melt pond, and sea ice ridge information for the ice services and ice researchers.