Allegra Gordon

Advisor: Dave Evans


Sea Ice is important as it helps cool the global climate because of ice’s high albedo. In my previous work I looked at the change in land cover, albedo and sea surface temperature of an Arctic scene from path 28, row 8 in Baffin Bay, between Greenland and North America.  Two Landsat-5 TM images were used to identify changes between two seasons: May 26, 1990 when ice fully covers the ocean and June 12, 1993 during ice melt. Four land classifications were interpreted as pure ocean water, mixed pixels with a low fraction of ice (such as ice chunks that are smaller than 30 meters floating in open ocean), mixed pixels with a high fraction of ice (such as melt ponds or slush), and pure ice.  These four classes were confirmed using K-Means and ISODATA unsupervised classifications, as well as by comparing the values from albedo and sea surface temperature calculations.

The area of water increased from May to June by 1,077%, coupled with a decrease of ice by 38%. The melting of ice, and in consequence, the increased coverage by water may be due to an increase in sea surface temperature of 13.5° K in June. In addition, the albedo of the sea ice scene decreased by 21%, from 0.593 in May to 0.365 in June. With a rise in temperature, a decrease of albedo and a land cover change favoring more water and less ice during the melt season, an ice-albedo effect may be at play. Although this study shows only the change between two seasons, there are implications for an ice-albedo effect that may trigger enhanced warming in the northern latitudes with worldwide consequences. This study will expand on this work by exploring other locations and times.