Airborne laser scanner (ALS) measurements along with a nearly coincident ENVISAT APP image were acquired in the Baltic Sea in March 2005 under cold conditions. The ALS data were processed to ice freeboard data. The data is analyzed using non-overlapping windows with a resolution of 300 m. First, a correlation analysis between different freeboard statistics and sigmadeg is performed. Then, using a nonlinear regression model the dependence between the mean sigmadeg and the mean freeboard is studied. The inversion from sigmadeg to freeboard obtained in this manner gave surprising good results. The whole SAR image (only HH polarization) was inverted using the same technique and the resulting freeboard histogram is discussed. Finally, the factors contributing to the results are shortly reviewed.
['Markku Similä', 'Marko Mäkynen', 'I. Heiler', 'Martti Hallikainen']
Comparison Between Envisat SAR and 3-D Laser Scanner Statistics for the Baltic Sea Ice