Passive microwave radiometer

Satellite based passive microwave radiometers have a coarse spatial resolution of approximately 30 to 70 km., and therefore small ice features will not be resolved by the antenna footprint. The only established classification with passive microwave radiometry is into open water, first year ice and multi year ice.
The radiometer data are useful for approximately estimating the ice edge position or the ice concentration. In the case of large areas with mixtures of pancake ice and open water, it is expected, that the passive microwave radiometry can give a coarse estimate of the ice concentration.
The used passive microwave radiometer data are from the Special Sensor Microwave/Imager (SSM/I) on the US-DMSP satellites, which gives a daily coverage in the Arctic area. On every pass of the satellite, data are recorded and written to the corresponding position in the output file. Therefore there are no accurate time information on the individual parts of the file, and the only knowledge is, that the data are recorded on the particular day.