On the relationship between spatial patterns of sea-ice type and the mechanisms which create and maintain the North Water (NOW) Polynya

Polynyas represent polar oceanic areas with anomalous low sea-ice concentra tions. The North Water (NOW) Polynya refers to a region at the northern end of Baffin Bay which encompasses three separate polynyas. This paper examin es the spatial patterns of sea-ice cover within the NOW region during the w inter, spring and fall of 1998 in the context of polynya formation and main tenance mechanisms. To accomplish this a sea-ice classification scheme for RADARSAT-1 ScanSAR imagery, obtained between 21 January and 7 December 1998 , was developed and implemented within a Geographic Information System (GIS ). The results identify a clear and consistent spatial structure of sea-ice co ver throughout the winter, spring and fall of 1998. Temporally, the polynya opened southward along the Canadian coast and westward away from the Green land coast. Comparison with parallel oceanographic, atmospheric and ice mot ion studies suggested that the polynya was primarily controlled by a latent heat mechanism with the exception of the west Greenland coast between Whal e Sound and Cape York. The underlying mechanism used to explain the polynya 's occurrence along this location is delayed ice formation during freeze-up and a resultant thinner winter ice cover causing earlier spring ablation t han surrounding areas. Arguments for oceanic and/or atmospheric sensible he at contributions are made.