HR: 0800h
AN: OS21A-09    [Abstracts]
TI: The Importance of Spatially Heterogeneous Roughness Grids on Hydrodynamic Modeling of Coral Reefs
AU: * Hoeke, R K
EM: hoeke@hawaii.edu
AF: Joint Institute for Marine and Atmospheric Research, Coral Reef Ecosystems Division, University of Hawai'i at Manoa, 1000 Pope Road Marine Science Building 312, Honolulu, HI 96822, United States
AU: Strolazzi, C
EM: cstorlazzi@usgs.gov
AF: Coastal and Marine Geology Program, US Geological Survey, Pacific Science Center 400 Natural Bridges Drive, Santa Cruz, CA 95060, United States
AU: Aucan, J
EM: jerome@hawaii.edu
AF: School of Ocean and Earth Science and Technology, University of Hawai'i at Manoa, 1000 Pope Road Marine Science Building 312, Honolulu, HI 96822, United States
AB: Hydrodynamics of two embayments in the Hawaiian archipelago, Hanalei Bay on the island of Kauai, and Kailua Bay, on the Island of Oahu, are estimated using a shallow-water finite-difference wave and circulation model. Both of the bay bottoms contain a mix of unconsolidated (mostly carbonate) sediment and fringing coral reefs. Model results of shoreline wave heights, shore-parallel and shore-perpendicular currents are found to vary by several orders of magnitude depending on what parameterization of bottom roughness is used. Several bottom roughness schemes are compared, including "standard" homogenous values for sediments, higher homogenous values for reefs, and spatially varying values derived from measurements of rugosity. Results from model runs using these different schemes are compared with in situ observations and indicate the importance of spatially heterogeneous roughness grids. Methods of: 1) deriving rugosity measurements from bathymetric data and 2) creating grids of hydraulic roughness lengths based on published values from the rugosity grids are presented. These methods have implications for providing near-real time bulletins and forecasts of water safety and water quality along Hawaii's coastlines.
DE: 4220 Coral reef systems (4916)
DE: 4262 Ocean observing systems
DE: 4534 Hydrodynamic modeling
DE: 4546 Nearshore processes
DE: 4560 Surface waves and tides (1222)
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly