Sand bed roughness in the nearshore, COAST 3D experiment, Egmond aan Zee, the Netherlands
By:  Robert L. Kendall
Contributors: Naval Postgraduate School (U.S.)
Publisher: Naval Postgraduate School; Available from National Technical Information Service
Published: 2000
Place of publication: Monterey, Calif; Springfield, Va
Language: eng
Format: Electronic resource
Number of pages: 78
Description: Sand bed roughness was measured in the near shore during a variety of hydrodynamic conditions using an array of seven 1 MHZ sonar altimeters mounted on the WESP (an amphibious vehicle used for measuring large-scale bathymetry) during the COAST 3D Experiment 1998, at Egrnond aan Zee, The Netherlands. Corollary waves were modeled using the Thronton and Guza (1983) wave transformation model. Wave height and current measurements were made in the surf zone using pressure sensors and electromagnetic current meters, and offshore wave heights were measured using an advectional wave-rider buoy. Measurements of sand bed roughness showed patterns similar to those observed by Clifton et al. (1971), but are highly variable both spatially and temporally with dependence on large scale morphology and wave and current conditions. Mobility number (Psi) calculated from the modeled wave field and also from measured currents revealed that roughness is a function of Psi. Roughness was observed to be highly variable at low Psi (< 100) calculated from the modeled wave heights. As Psi increased (100-150), roughness decreased gradually, but was still highly variable. As PSI reached values greater than 150, roughness was restricted to the lowest observed values (< 3 cm) implying planar beds under sheet flow conditions.
Notes: Thesis advisor(s): Gallagher, Edith L. ; Thornton, Edward B.

"June 2000."

Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, June 1998.

Includes bibliographical references (p. 75-76).

Approved for public release, distribution unlimited--Cover.

Also available online.

Mode of access: World Wide Web.

System requirements: Adobe Acrobat reader.

US Navy (USN) author.

updated dlb 11/2/06