Radar backscatter measurements from Arctic sea ice during the fall freeze-up

C-band radar backscatter from sea ice increases dramatically during the fall freeze-up. Measurements taken from a ship-borne scatterometer during the International Arctic Ocean Expedition (IAOE) ´91 show that this increase is 15-20 dB at incidence angles from 25° to 35°. This increase in backscatter is shown to be due mainly to a transformation from primarily surface scattering to primarily volume scattering through the use of simple scattering models. The re-freezing of moisture on or near the sea ice surface is believed to cause the increase in volume scatter. The authors applied a coherent noise reduction scheme to these data to improve the quality of the measurements and to remove systematic noise sources that corrupt the measurements. This scheme reduces coherent noise sources by 10 to 20 dB