Using ERS-1 SAR data to monitor the state of the Arctic Ocean sea ice surface between spring and autumn, 1992

Records of ERS-1 SAR backscatter intensity from sea ice between spring and autumn were compiled for two regions of the Arctic Ocean. Before the onset of snow melt in spring and after the onset of freezing in autumn, sea ice backscatter is typically -10 dB. Minimum backscatter values of -19 dB occur in early to mid-June when the area of melt pools on floes is at a maximum. Backscatter increases to roughly -13 dB during the summer as the area of melt pools decreases. Backscatter is sensitive to the onset of freezing in autumn, when melt pools freeze over and the amount of liquid water within and at the surface of the ice decreases, and surface and volume scattering leads to increased backscatter of about -10 dB. The results indicate that spaceborne SAR offers the opportunity to monitor the spatial variations of numerous important geophysical parameters such as the timing of the onset of snow melt and the complete loss of the snow cover, melt pool area and albedo, and the timing of freeze-up in autumn