Vol. 4, No. 1, 130-138, 2005
Eric Hudier and Pierre Larouche
Abstract For smooth wet surfaces the
backscattering at normal incidence is dominated by the coherent component. In
addition, the non-coherent component is maximum at normal incidence. The variability
in surface slope orientations being a characteristic of ridge areas, we
computed probability densities that pixels from ridge regions would be
identified as ridge pixels. Both coherent and non-coherent models show a
dependence on block size and the applied threshold value. As anticipated, the
coherent model gives the highest probability levels with a maximum for cubic
blocks of 0.4 m. The maximum value with non-coherent backscattering is reached
for 1 m blocks.
Citation EARSeL European Association of Remote Sensing Laboratories, Strasbourg, France BIS-Verlag
During the early melt period, the air-ice and
air-snow temperature conditions may vary from melting to freezing within 12
hours. When solar irradiance and air temperature are at their maximum, the
increased wetness of the snow layer coupled with the development of a liquid
film on exposed ice faces increases the contrast between ridges and flat ice
areas. We present two images recorded at 4 am and 4 pm that show this
natural enhancement process of ridges when a liquid phase is present on ice
blocks (4 pm). Besides, it also shows that, on the contrary, the development
of new ice crystals during the night create conditions that highly reduce the
contrast between ridges and flat ice areas (4 am image).
View Full Text (pdf file, 180 kB)
History
Submitted: 07 June 2003
Revised: 31 March 2005
Accepted: 14 Sept 2005
Hudier E & P Larouche, 2005. A potential of polarimetric SAR data in mapping
first year sea ice pressure ridges from the coherent and non-coherent components of HH and VV channels. EARSeL eProceedings, 4(1), 130-138
BIS Library and Information System, Carl von Ossietzky University of Oldenburg
ISSN 1729-3782