W. Aldenhoff, L.E.B. Eriksson, Y. Ye and C. Heuzé (2020), First-year and Multiyear Sea Ice Incidence Angle Normalization of Dual-polarized Sentinel-1 SAR Images in the Beaufort Sea, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. vol 13, pp 1540-1550, doi: 10.1109/JSTARS.2020.2977506

Obs: W. Aldenhoff was then a PhD student under my supervision (graduated 2020).

Last paper of Wiebke’s PhD to be published (see also [12], [18] and [19]), although this work was among the first executed. The reason? It is common practice to normalise the backscatter by the incidence angle, but we wondered:

• does this normalisation really improve on the results?
• and what is the best way to perform the normalisation?

Using some rare near-coincidental ascending and descending images from Sentinel-1, we could retrieve the slopes backscatter / incidence angle for sea ice, for HH and HV. And the short answer is: yes, normalisation does make a big difference for automatic ice classification and for mosaicing. This is especially true for multi year ice, whose backscatter depends on its age.

One issue remains: first year ice backscatter still is too close to the noise level, to the point that the first subswath cannot be used.

Fig 10 of Aldenhoff et al. (2020) showing the effect of the normalisation when mosaicing.

Download the full-text here.