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Frictional wave dissipation on a remarkably rough reef
Author(s) -
Monismith Stephen G.,
Rogers Justin S.,
Koweek David,
Dunbar Robert B.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl063804
Subject(s) - reef , dissipation , geology , atoll , coral reef , submarine pipeline , oceanography , fringing reef , coral , physics , thermodynamics
Abstract We present a week of observations of wave dissipation on the south forereef of Palmyra Atoll. Using wave measurements made in 6.2 m and 11.2 m of water offshore of the surf zone, we computed energy fluxes and near‐bottom velocity. Equating the divergence of the shoreward energy flux to its dissipation by bottom friction and parameterizating dissipation in terms of the root‐mean‐square velocity cubed, we find that the wave friction factor, f w , for this reef is 1.80 ± 0.07, nearly an order of magnitude larger than values previously found for reefs. We attribute this remarkably high value of f w to the complex canopy structure of the reef, which we believe may be characteristic of healthy reefs. This suggests that healthy reefs with high coral cover may provide greater coastal protection than do degraded reefs with low coral cover.