Microtopographical roughness of shallow-water continental shelves

High-resolution (<1 cm) roughness height measurements were made of the seafloor at seven locations on continental-shelf sediments on water depths ranging from 18 to 50 m. Roughness profiles of the sediment-water interface were digitized primarily from stereo photogrammetric measurements of varying pathlengths and increments. The data show that the root-mean-square roughness height varies from 0.3 cm for flat, featureless bottoms to 2.3 cm for rippled bottoms. Slopes of the roughness power spectra were calculated to be -1.5 to near -3.0 and depended to a large extent on contributions in higher spatial frequencies due to coarse sediments. Correlation lengths of different bottom types were estimated by using the Weiner-Khintchine theorem and examining the low-frequency behavior of the roughness spectra derived from the longest roughness profiles.

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