Classification of Baltic Sea ice with airborne microwave radiometer

A helicopter-borne multifrequency radiometer (24, 34, 48 and 94 GHz, vertical polarization) was used to investigate the behaviour of the brightness temperature of different sea ice types in the northern Baltic Sea. The measurements were made in dry and wet conditions (air temperature above and below 0/spl deg/C). The angle of incidence was 45/spl deg/ in all measurements. The aim of the investigation is to determine: (a) frequency dependency of the brightness temperature of different ice types, (b) the capability of the multifrequency radiometer to classify ice types, and (c) the optimum measurement frequencies for sea ice mapping.>