Optimal Use of Multibeam Technology in the Study of Shelf Morphodynamics


Many of the recent advances in our understanding of sedimentary processes on the continental shelf have come about as a result of the use of multibeam sonar systems. These systems provide wide area coverage of seafloor variations in bathymetry and backscatter at typical horizontal resolutions as small as ∼ 2% of the water depth. The narrowest beam systems now provide backscatter data at resolutions approaching towed sidescan sonar while simultaneously providing co‐registered, equivalent‐resolution topography.

Even more valuable than the static view of the seabed is an ability, through resurvey, to monitor temporal variations in the seabed. By adding the time dimension, insights can be provided into the sedimentary processes rather than just the resulting sediment distribution. To achieve this, however, requires particular attention to be placed on the limitations of these survey systems, which affect repeatable accuracy. To assess the total achievable accuracy one needs to account for all the integrated components of the survey system.

In this paper, the contributions of the various sources of systematic bathymetric and backscatter error within a typical shelf multibeam survey are described. To optimize the bathymetric data, strategies for dealing with imperfections in tidal models and knowledge of the sound speed structure are described. In order to improve the backscatter data, strategies for predicting the combined effect of beam pattern residuals and the seabed angular response are detailed.

To illustrate a typical result, a pair of overlapping surveys employing widely differing source sensor resolution and accuracy is combined to try to predict the relative importance of active and relict shelf morphodynamic processes. Sediments, Morphology and Sedimentary Processes on Continental Shelves Sediments, Morphology and Sedimentary Processes on Continental Shelves: Advances in Technologies, Research, and


Center for Coastal and Ocean Mapping

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Sediments, Morphology and Sedimentary Processes on Continental Shelves: Advances in Technologies, Research, and Applications



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Book Chapter