L.L. Sutherland

The Discrimination Of Sea Ice Types Using Sar Backscatter Statistics

X-band (HH) synthetic aperture radar (SAR) data of sea ice collected during the Marginal Ice Zone Experiment in March and April of 1987 was statistically analyzed with respect to discriminating open water, first-year ice, multiyear ice, and Odden. Odden are large expanses of nilas ice that rapidly form in the Greenland Sea and transform into pancake ice. A first-order statistical analysis indicated that mean versus variance can segment out open water and first-year ice, and skewness versus modified skewness can segment the Odden and multilayer categories. In additions to first-order statistics, a model has been generated for the distribution function of the SAR ice data. Segmentation of ice types was also attempted using textural measurements. In this case, the general co-occurency matrix was evaluated. The textural method did not generate better results than the first-order statistical approach.

Sar And Passive Microwave Observations Of The Odden During Mizex '87

The Odden, a protuberance of sea ice in the Greenland Sea Basin, was studied using the NIMBUS-7 scanning multichannel microwave radiometer (SMMR) satellite and an X-band (3 cm) synthetic aperture radar (SAR) aircraft. The sea ice, meteorological, and oceanographic conditions within the northern portion of the Odden were also studied in March and April 1987. The SMMR data, which were first validated with in situ ship measurements and the SAR data, showed rapid 2-4 day oscillations of the Odden ice edge. The oscillations at 74-75 deg N were several hundred kilometers in extent. The rapid oscillation of the Odden does not appear to be a result of wind-induced ice drift, but rather results from the rapid formation of thin ice off the main ice edge.

A Comparison Of Ice Concentration Estimates From Sar And SSSM/I Data

Remote sensing data collected during the March 1988 Alaska survey is used to compare multiyear ice concentration estimates derived from a satellite mounted passive microwave radiometer to those generated by an aircraft mounted Synthetic Aperture Radar (SAR) system. The passive microwave radiometer data used is produced by the Special Sensor Microwave Imager (SSMII) which is a multichannel system. The SSMII ice concentration estimates are produced by a multichannel algorithm which utilizes both the polarization and spectral gradient radiance ratios to determine the percent of multiyear ice. These estimate are compared to concentration estimates produced by a manual interpretation of mosaicked SAR imagery. A 30 percent discrepancy was found in the multiyear ice concentration estimates for coincident imagery which crosses the first-yearlmultiyear ice edge.

Geophysical Information On The Winter Marginal Ice Zone Obtained From Cearex Sar Data

During the 1989 Coordinated Eastern Arctic Experiment (CEAREX) a total of sixteen synthetic aperture r adar (SAR) data collections were flown. Each mission covered approximately a 100 x 200 km area surrounding the ice strengthened vessel M/S POLARBJORN. SAR viewing geometries, frequencies, and polarizations varied based on the objectives of each individual mission. On-board processors enabled personnel stationed at Svalbard and Andoya for flight coordination to review the real-time data. Observations and interpretations including ice edge, type, concentration and floe size made from this imagery were used to plan successive SAR missions and were transmitted to POLARBJORN enabling scientists on-board to select areas of special interest for intensive study and sea truthi ng .

Multi-frequency SAR, SSM/Ii And AVHRR Derived Geophysical Information Of The Marginal Ice Zone

A description is given of the fusion of synthetic aperture radar (SAR), special sensor microwave imager (SSM/I), and NOAA Advanced Very High Resolution Radiometer (AVHRR) data to study arctic processes. These data were collected during the SIZEX/CEAREX experiments that occurred in the Greenland Sea in March of 1989. Detailed comparisons between the SAR, AVHRR, and SSM/I indicated: (1) The ice edge position was in agreement to within 25 km, (2) The SSM/I SAR total ice concentration compared favorably, however, the SSM/I significantly underpredicted the multiyear fraction, (3) Combining high resolution SAR with SSM/I can potentially map open water and new ice features in the marginal ice zone (MIZ) which cannot be mapped by the single sensors, and (4) The combination of all three sensors provides accurate ice information as well as sea surface temperature and wind speeds.