Analysis of surface-based passive microwave observations during LEADEX 1992

There are several recognized varieties of thin ice depending on whether the ice growth occurs under calm conditions or in the presence of waves, precipitation, or blowing snow. Two main types, congelation ice and frazil ice, are distinguished by their crystal structure, and each of these can have quite different salinity and brine volume distributions. Grenfell et al. (1993) has shown that the temporal evolution of the passive microwave signatures of these types can be quite different. Due to the logistical difficulties in observing thin ice in the polar regions, most of the information on the development of passive microwave signatures of thin sea ice has been obtained from experiments on ice grown in a pond at the Cold Regions Research and Engineering Laboratory (CRREL) in Hanover NH. An experiment dedicated to studying the properties of sea ice growing in Arctic leads (LEADEX 92) was carried out during March and April 1992 in the southern Beaufort Sea about 160 km north of Prudhoe Bay, Alaska. The present authors participated in this effort in order to obtain passive microwave observations of thin sea ice growing under natural conditions.