DECAY OF A HIGH ARCTIC LAKE-ICE COVER - OBSERVATIONS AND MODELING

The decay of a lake-ice cover in the Canadian High Arctic was studied for 2 years. Melt at the upper surface accounted for 75% of the decrea se in ice thickness, while 25% occurred at the ice-water interface, An energy-balance model, incorporating density reduction due to internal ice melt, was used to simulate the decay of the ice cover. The overal l performance of the model was satisfactory despite periods when compu ted results differed from the observed ice decay. Energy-balance calcu lations indicated that the absorption of shortwave radiation within th e ice provided 52% of the melt energy while 33 and 15% came from the s urface-energy balance and heat flux from the water.