Incidence angle dependence of the mean C-band HH-polarization backscattering signatures of the Baltic Sea ice

RADARSAT ScanSAR Narrow images are currently utilized operationally by Finnish Ice Service to monitor Baltic Sea ice conditions. Automatic identification of different ice types and open water in the SAR images is studied by the Finnish Institute of Marine Research (FIMR). Successful implementation of the classification algorithms is complicated due to the significant changes in backscattering level and contrast caused by the large incidence angle variation (up to 20 degrees) in one ScanSAR image. To quantify and to compensate, at least partly, the effects of the incidence angle variation, we determine the incidence angle dependence of the mean backscattering coefficient (oo) values of various Baltic Sea ice types using helicopter-bome scatterometer data and RADARSAT images. The results are also compared with theoretical backscattering models.