On the Role of Spatial Sea-Ice Roughness in Understanding Sea-Ice Properties, Processes and Their Changes

The alarming retreat of the Arctic sea-ice cover, highlighted by the record lows in 2002 and 2003, calls for increased research aiming at understanding the role of sea ice in coupled ocean-ice-atmosphere models, and at understanding sea-ice properties and processes leading to its formation, metamorphosis and reduction - both as a prerequisite for modeling and as basic geophysical knowledge on the geophysical system ``Arctic Sea Ice". Surface roughness plays a key role in energy exchange, ice formation and melting. By mathematically formalizing, measuring and analyzing spatial surface roughness, we can derive information on properties of the sea ice and its snow cover whose direct observation is impossible or too costly. Since any models can only be as good as the data they are based on, we present mathematical methods for extraction of surface roughness information from a range of satellite and airborne data, including AMSR, PSR, and RADARSAT SAR data, as well as novel approaches to surveying surface roughness and high-resolution topography using ice-surface roughness surveys (GRS surveys) in the field and laser profiling from unmanned aerial vehicles (UAVs). By means of a classification approach, information on sea-ice properties and sea-ice morphogenetic processes is derived from spatial surface roughness, including roughness length as required for atmospheric and climatic modeling. The approach will be demonstrated in case studies using sea-ice and snow-cover data from the Chukchi and Beaufort Seas.