Interpretation of Passive Microwave Imagery of Surface Snow and Ice: Harding Lake, Alaska.

摘要

This report presents interpretations of snow and ice on Harding Lake, Alaska, using 33.6-GHz passive microwave imagery acquired from 1500 m on 8 and 11 March 1988, when snow conditions were dry and wet, respectively. Field data used include an aerial video mosaic, ice column descriptions, snow observations and an impulse radar trace. Our results show that low-altitude passive microwave imagery is a promising method for remote/field investigation of large-scale lake ice processes. Fracture patterns in the lake ice were detected where snow ice had formed above the near cracks in the ice cover. Presumably, bubbles in the snow ice layer scattered less energy than the depth hoar crystals over the adjacent ice surface resulting in warmer brightness temperatures over fractures. Brightness temperatures of a continuous and deeper snowcover at the northwest end of the lake were low compared to the combined radiance of snowdrifts and pockets of bare ice across the lake surface.