See SEACOOS (Southeast Atlantic Coastal Ocean Observing System) for an overview of the entire project – it involves investigators from NC, SC, GA, and FL. Georgia Tech Savannah’s role in the project is related primarily to real-time measurements of directional wave energy spectra at a nearshore site. In this instance the site is near the Savannah River Entrance Channel. Why measure waves? Well, for many of the same kinds of reasons we measure meteorological parameters. There are both practical and research-related reasons. The data are valuable on a daily basis for boaters, for search and rescue personnel, port operations, and pilots. Long-term records are particularly valuable for engineering applications such as beach erosion prediction or beach nourishment design. Waves play a role in controlling coastal circulation, which has an impact upon many organisms, and water quality.

There are different ways to measure directional waves. Skidaway Institute of Oceanography is presently using a radar system to measure currents on the continental shelf (see www.skio.usg.edu/research/sabsoon/WERA/), and these systems have been used to measure waves as well. But in situ measurements are still the most reliable means. Triaxys wave buoys have been deployed as part of the Georgia SEACOOS effort since 2004. These buoys are 1 m in diameter, 200 kg, and include three accelerometers and three angle rate sensors to quantify the movement of the buoy. This in turn allows onboard computation of wave parameters, which are then transmitted using both Iridium and Inmarsat-D+ satellite telemetry systems. Data are then made available via an Internet page. This page (wavebuoy.gtsav.gatech.edu) includes a document describing comparisons to independent measurements via an ADCP (acoustic Doppler current profiler). The photo below shows a buoy being loaded onto the deck of the R/V Savannah at the dock at the Skidaway Institute of Oceanography.

This system complements other measurements further offshore, at a series of towers maintained by the US Navy. These do not provide directional wave information, however, so we have been exploring alternative means of obtaining this data. One approach that appears to have promise involves the use of digital video. A GT-Savannah student (Jeseon Yoo) completed a Ph.D. thesis in 2007 that involved the use of digital video for identification of wave properties and bathymetry in nearshore regions. The image below shows one of the Navy towers in Georgia, with three digital video cameras deployed for a short-term experiment on measuring waves with video.