on the iceberg detection/identification 

 problem (Desjardins and McRuer, 1996; 

 Willis et al., 1996). These studies 

 illustrated some of the difficulties inherent 

 in the iceberg detection/identification 

 problem. The lack of predictability of 

 iceberg distribution and lifespans over the 

 timescales required for satellite SAR data 

 acquisition, unpredictability of weather and 

 visibility for photographic ground truth 

 collection, and the relatively low dielectric 

 constant of glacial ice, which inhibits 

 microwave radar detection, are among 

 these challenges. 



Study Development 



In early 1996, International Ice 

 Patrol began conducting a test of 

 RADARSAT's ability to detect 

 icebergs, as part of the Applications 

 Development and Research 



Opportunities (ADRO) Program. The 

 RADARSAT SAR, a Canadian 

 satellite operation, was launched in 

 1995. A C-band HH polarization 

 microwave radar instrument, it is 

 capable of gathering terrestrial and 

 ocean surface data day or night and 

 is virtually unaffected by fog or 

 weather. In addition, its greater 

 flexibility in terms of user-selected 

 beam modes, incidence angles and 

 resolutions presents a great 

 advantage in specifying the operating 

 requirements for detecting point 

 targets (Raney et al., 1991). Vachon 

 et al., (1997) advocate image mode 

 ScanSAR Narrow (SCN)-Far as a 

 good compromise between swath 

 size and resolution or smallest- 

 detectable target when pursuing 

 vessel detection. After some 



consideration, however, the need to 

 detect growlers and small icebergs at 

 dimensions smaller than those 

 expected for vessels places a heavier 

 emphasis on more fine-scale 



resolutions, requiring a sacrifice in swath 

 size. For iceberg detection, we eventually 

 assumed that beam-mode W2 would be 

 more useful, given the finer resolution, 

 moderately high incidence angle, and 

 reasonably large swath width, though 

 growlers would certainly not be detected by 

 this beam-mode. We planned to compare 

 the targets detected in the RadarSat 

 images with those detected by HP's visual 

 and airborne radar observations. 

 Operational constraints required that the 

 study be conducted without allocation of 

 additional funding or personnel. In 

 addition, any ground-truthing had to be 

 done without significantly impacting MP's 

 primary responsibility of performing iceberg 



North 



Figure 2. The box marks the bounds of the RADARSAT 

 scene taken at approximately 09:40 UTC. The aircraft, CG- 

 1503, departed St. John's airport at approximately 10:10 UTC 

 and proceeded northward to the operation area, detecting the 

 final contact within the footprint area at 13:23 UTC. The 

 locations of icebergs are marked by triangles, with the 

 corresponding index number shown. Ship icons indicate 

 vessel positions at the time of aerial detection. The island of 

 Newfoundland is shown in gray in the lower left area of the 

 figure. 



57 



