TEMPORAL EVOLUTION OF PHYSICAL AND DIELECTRIC-PROPERTIES OF SEA-ICE AND SNOW DURING THE EARLY MELT SEASON - OBSERVATIONS FROM SIMS 90 EXPERIMENT

The first field experiment in the 5 year seasonal Sea Ice Monitoring S ite (SIMS) program was conducted in Resolute Passage, Canadian Eastern Arctic, between 15 May and 8 June 1990. This period signals the early melt season of sea ice in that region. A standard array of ice and sn ow measurements was collected on a daily basis from first-year and mul ti-year ice to monitor temporal evolution. Measurements included ice s alinity, ice temperature and ice-surface roughness, snow salinity, sno w temperature, snow density and snow depth. The complex dielectric con stant of sea ice was computed from these measurements. Rapid desalinat ion of first-year ice was noticed in the sur-face layer. Towards the e nd of the experiment period, salinities of the snow-hoar layer were hi gher than those of the ice-surface layer. Variation in air temperature is replicated by ice-surface temperature but not by the salinity or d ielectric properties. No temporal variation in permittivity and dielec tric loss was observed for first-year ice, but a slight increase in bo th parameters was observed for multi-year ice. As a result, a slight d ecrease in the microwave-penetration depth was observed for multi-year ice. Physical properties of ice and snow were compared against result s obtained from other experiments conducted in different ice-formation regions in the late winter and in the early melt season.