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time consuming (approximately 12 hours of sonar imaging time was required for the Scots
Bay area versus less than 1 minute for the InSAR image) and are thus expensive. They
typically focus only on small areas where subsurface features are already known to exist.
The airborne InSAR, by contrast, can easily cover thousands of square kilometers in a
single day, allowing it to locate features which were previously unmapped, such as the
dune field SW of Advocate Harbour. The survey ships are also unable to map certain area
because of navigation hazards (such as the dangerous currents near Cape Split) but these
areas pose no problems for the InSAR.
The ideal operational solution for subsurface feature detection is probably to use airborne
InSAR to cover large areas where it can provide the location of subsurface features which
may pose potential hazards. These locations could be noted as potential shipping hazards
and the charts filled in with more detail when sonar survey ships became available to map
the areas which had already been identified by the InSAR. Since the sonar surveys would
be directed to specific areas, the overall cost of surveying a large area could be reduced.
ACKNOWLEDGEMENTS
The authors would like to acknowledge and thank Marco van der Kooij for his significant
contribution to the planning and execution of the Bay of Fundy experiment, and for his
contribution to data analysis software and early results from this experiment. The
contribution from the crew and sensor operators on the CCRS Convair 580 is also
gratefully acknowledged.
REFERENCES
Ainsworth, T. L., M. E. Cannella, S. R. Chubb, R. A. Fusina, R. W. Jansen, G. O.
Marmorino and G. R. Valenzuela, 'InSAR Imagery of Surface Currents, Wave Fields and
Fronts’, Proc. of IGARSS '94, 1720-1722, 1994
Alpers, W. R., D. B. Ross and C. L. Rufenach, ‘The detectability of ocean surface waves
by real and synthetic aperture radars’, J. Geophys. Res., 86, 6481-6498, 1981
Goldstein, R. M., F. Li, J. Smith, R. Pinkel and T. P. Barnett, ‘Remote sensing of ocean
waves: The Surface Wave Process Program experiment’, J. Geophys. Res., 99, 7945-
7950, 1994
Goldstein, R. M. and H. A. Zebker, ‘Interferometric radar measurement of ocean surface
currents’, Nature, 328, 707-709, 1987
