Mi. Pettersson et al., SAR OBSERVATIONS OF ARCTIC FREEZE-UP COMPARED TO SSM I DURING ARCTIC-91/, International journal of remote sensing, 17(13), 1996, pp. 2603-2624
Ice concentration in the Arctic derived from ERS-1 Synthetic Aperture
Radar (SAR) and Special Scanning Microwave/Imager (SSM/I) images are c
ompared. The satellite data are compared to video images and in situ m
easurements. The data were acquired during the freeze-up period of the
ARCTIC'91 expedition. The studied areas were characterized by melting
conditions and new ice formation with frost flowers. The ERS-1 SAR im
ages are classified by a local averaging method and a segmentation met
hod. Parameters for the methods are derived from the backscattering di
stributions. Temporal sequences and meteorological information are use
d for consistent results. Ice concentration derived from SAR are compa
red with the SSM/I ice concentration (NASA team algorithm) and ship ob
servations. SSM/I may underestimate the ice concentration by 20 per ce
nt due to thin ice formation and melting conditions while SAR may over
estimate. However, by using the SAR estimate of the different ice clas
ses we believe it is possible to increase the accuracy of the NASA tea
m algorithm. We conclude that it is important to compare results from
different sensors and methods.