Md. Coon et al., MICROWAVE RESPONSE TO STRESS IN SEA-ICE - A REPORT ON INITIAL FIELD-TESTS, Cold regions science and technology, 25(1), 1997, pp. 79-83
An initial field test was conducted to determine if the stress state o
f sea ice has an effect on its microwave signature. The tests were con
ducted during March and April of 1992 in the Beaufort Sea. An inflatab
le jack was placed into a vertical slot in the ice to induce stress in
the ice while a microwave transmitter/receiver monitored the backscat
ter from the ice. Measurements were made at X-Band and C-Band frequenc
ies, with various polarization combinations, on 1.3 m thick first-year
ice and on a freshwater melt pond within a multiyear flee. Changes in
backscatter were seen in both the first-year ice and the melt pond ic
e at both X-Band and C-Band frequencies, but not at all polarizations
and orientations. In general, the largest change in microwave response
took place when the ice was pressurized for the first time. The measu
red changes in microwave response were less than 2 dB. However, after
accounting for the mismatch between the radar footprint and the size o
f the area stressed, the effect on the backscatter signal was 13 dB. R
esponse was seen at jack pressures at low as about 70 kPa, which resul
ted in an average stress over the radar footprint of about 13 kPa. In
comparison, natural pack ice stresses range up to 400 kPa.