Fluid-Sediment Interactions in the Nearshore
STATE UNIV OF NEW YORK AT STONY BROOK MARINE SCIENCES RESEARCH CENTER
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LONG-TERM GOALS. The long range goal of this research is to identify and understand the relevant small scale processes of coastal sediment transport which are necessary for inclusion in numerical models for the evolution of larger scale coastal morphology. OBJECTIVES. The immediate objectives of this project are to examine the relevant importance of various time and space scales of sediment transport. In particular, we are in the process of determining whether coastal sediment transport can be envisioned as the aggregate of a limited number of separate transport components which are differentiated by their temporal scales. As well as identifying what these components are, we are also examining how these components vary as a function of incident forcing, location within the surf zone and vertical position. APPROACH. Seven weeks worth of measurements of the vertical profile of sediment concentration and fluid velocity from a 2-D grid which spans the surf-zone have been collected as part of the Sandy Duck experiment which was held during September and October 1997 at the USACOE field research facility at Duck, North Carolina. These measurements were obtained from stacks of fiber-optic back-scatter sensors FOBS collocated with vertical arrays of electro-magnetic current meters VEMA. These measurements will be used to estimate the temporal and spatial distribution of sediment flux over the surf-zone. The frequency distribution of sediment flux will be determined from the cross-spectra of concentration and velocity and the flux will be partitioned into mean, incident and infra-gravity components. This information will be examined to identify the relative importance of these components as a function of surf-zone location and fluid forcing as well as to determine the importance of the divergence of these components on morphologic evolution.
- Physical and Dynamic Oceanography
- Hydrology, Limnology and Potamology