Technical note Surface temperatures and sea ice typing for northern Baffin Bay

Abstract

Abstract The northern region of Baffin Bay (74°-79° N and 70°-78° W) is known as the North Water Polynya—a region of inhomogeneous ice cover during the winter and spring months. During the winters of 1978/79 and 1980/81, a series of low-level aircraft flights were conducted over the North Water covering a length of 2300 km. Surface thermal infrared (TIR) temperatures were measured and visual surface ice characteristics photographed with the aid of a searchlight attached to the aircraft. Corrections procedures were applied to the TIR data which produced a temperature accuracy of ± 0·15°C. A matching was made between visual ice types and ice surface temperatures along with ice properties using the aircraft and ice/meteorological data collected at a base station near Resolute Bay, Northwest Territories. Also, surface temperatures outside the spatial extent of the aircraft measurements were extrapolated by means of NOAA-VHRR TIR imagery. From the two sets of data, regional surface temperature maps were constructed. Results indicated that grey-white ice for thicknesses of 0·15-0·3 m was the dominant type of ice especially during January and Feburary with a marked increase of white ice percentage towards the end of the ice season. Ice-free areas or warm water actually constituted only a very small percentage of the total area for both winter seasons.