Observations of Mean and Oscillatory Surface Flow in the Surf Zone
Abstract
Spatial variations in nearshore circulation often tend to occur on scales much larger than can be observed with traditional in situ arrays of instrumentation. Thus, complex numerical models designed to simulate these larger scales must rely on generally sparse field measurements to verify the accuracy of predictions. Incorporation of data into models using data assimilation techniques is helpful in keeping models tuned to the observations, and potentially enhancing their predictive capability into useful forecasts for various marine applications. Increasing the density of observations can further improve model performance, and if data is obtained in near real-time then models can be used in an operational sense on site to guide experimental design, distribution of resources, or coastal managerial and strategic military decision making. In this work, we discuss an observational technique to measure in near real-time mean and oscillatory flow over the large spatial scales associated with typical nearshore circulation. Observations of surface flow are derived from Particle Image Velocimetry (PIV) techniques applied to field data obtained from land-based video cameras obliquely oriented to overlook the surf zone. The remote nature of the video observations allows for large regions to be examined, and arrays of such cameras to extend the region of interest to many times present day capabilities. Difficulties arise when the resolution of the imagery degrades with distance from the camera; thus, the usefulness of the video-based PIV technique depends on the spatial extent over which the observations can be made. We will present observations obtained from recent field experiments that demonstrate the usefulness and limitations of the PIV techniques for typical deployments. This work was supported by the Office of Naval Research, Coastal Dynamics program.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2002
- Bibcode:
- 2002AGUFMOS71A0240L
- Keywords:
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- 3020 Littoral processes;
- 4512 Currents;
- 4546 Nearshore processes