Alignment of L- and C-Band SAR Images for Enhanced Observations of Sea Ice

This paper discusses the alignment of Synthetic Aperture Radar (SAR) image pairs with one image acquired at L- and the other at C-band. For our study we used data from ALOS-2 PALSAR-2 and Sentinel-1 taken over sea ice in the Fram Strait. The use of multifrequency SAR data is beneficial for sea ice characterization and classification because it combines the advantages of the frequency dependence of signal penetration depths and backscattering characteristics due to small-scale ice properties. For drifting sea ice, however, an immediate combination of image pairs acquired with a time gap is usually not possible. Such cases require to consider the effects of ice drift. In this study we investigate the possibility to compensate for sea ice drift for separation in acquisition time ranging from a few hours to several days. The first results are promising and suggest that alignment of SAR image pairs obtained at different frequencies is possible even for larger time gaps between acquisitions if drift and deformation can be estimated reliably.