An Investigation of Surface Currents and Internal Waves over the Inner and Mid-Shelf during the DUCK94 Experiment


Investigators

Hans C. Graber, Lynn "Nick" K. Shay, Brian K. Haus

Funding Source

Office of Naval Research, Coastal Dynamics and Remote Sensing Programs

Objectives

The overall scientific goal of this study is to understand the dynamics and temporal and spatial variability of the circulation over the inner to mid-shelf region and to examine which mechanisms and interactions are responsible for observed surface flow features. A better understanding of the shelf circulation and its scales of variability is critical to improve the fundamental understanding of larval dispersal (and settlement) rates and the ocean and sediment dynamics.

Approach

During DUCK94, a dual frequency HF (25.4 MHz) Doppler radar was deployed to map the surface current vectors in "near real" time and at high spatial and temporal resolution over a wide region in shallow coastal waters from two shore-based sites. To map the surface vector currents over a 700 km2 area the RSMAS Ocean Surface Current Radar (OSCR) system was deployed along the shoreline near the U.S. Army Corps of Engineers Field Research Facility (FRF) during the month of October 1994. The OSCR system consists of two stations that transmit and receive radar signals. The two stations were separated by a distance of about 27 km with a range of about 45 km with a spatial resolution of 1 km. Maps of surface vector currents were collected every 20 minutes.

Our goal is to use these high resolution and accurate surface current vectors to perform a combined analyses of this data set with subsurface point measurements to determine more precisely which mechanisms drive the ocean circulation over the continental shelf. Our analyses will determine estimates of the contributions to the observed shelf flow due to internal wave dynamics, wind-driven currents, tidally forced motions and the effect of the surface gravity wave field. Specifically, we will proceed as follows:

Results

For a list of addresses of the investigators involved in Duck 94 click here.