Gulf Stream Research
The Gulf Stream is a powerful, warm body of water that originates in the Gulf of Mexico and flows northward off the Atlantic coast. While it has no true physical boundaries, the shape of the coastline and bathymetry of the seafoor off the Outer Banks bring it within 15-20 miles off Cape Hatteras. Traveling at a speed of approximately 5 miles per hour, the Gulf Stream has more power than all of world’s rivers combined, transporting nearly 2.5 billion cubic feet of water per second off of Cape Hatteras. Harnessing just .1% of the available power would yield 300GW of power, the equivalent of 150 nuclear power plants. UNC CSI scientists are assessing this potential for power generation and how we might tap into the power of the Gulf Stream for grid scale implementation.
UNC CSI Scientists are currently conducting research to locate the “sweet spot” for capturing the power of the Gulf Stream. The correct placement of marine hydrokinetic devices is critical for capturing Gulf Stream energy. The seafloor depth in the middle of the Gulf Stream can be 10,000 feet or more, making mooring any device extremely difficult, if not impossible. Because of this constraint, the mooring of any devices would need to be along the continental shelf slope, yet in an area that is within the meandering Gulf Stream flow the majority of the time. UNC CSI scientists are currently targeting an area off Cape Hatteras in 250-300m (820-980 ft) of water.
Because of the variability of the location of the western edge of the Gulf Stream, UNC CSI researchers are using a variety of devices to measure the flow within the study area and are comparing these measurements to computational models to help improve the predictive capability of these models.
A moored Acoustic Doppler Current Profiler (ADCP) has been deployed in approximately 275m of water within the study area since 2013. This device uses acoustic signals to measure current speed and direction in predetermined increments from the sea floor to the surface in one location. The data is recorded on board and the device must be serviced annually. To retrieve the ADCP, an acoustic signal given from the surface will release the pod from a small sacrificial plate and the device will float to the surface for recovery. Once back on board, the ADCP can be serviced and the data downloaded.
Regular transects are performed across the continental shelf through the Gulf Stream using a boat mounted ADCP. Unlike the moored ADCP, this method gives us a snapshot of the Gulf Stream flow across the shelf and out into the deeper water of the Stream.
Surface current data is acquired with high frequency Coastal Ocean Radar (CODAR) locations in Duck, Cape Hatteras and Core Banks, NC. CODAR, is a land based HF (5 MHz) radar system that use the doppler shift in an electromagnetic wave reflected off of waves on the ocean surface to determine the ocean surface currents in the top 2-3 meters. The radars are able to measure the currents every hour consistently, helping scientists observe changes in the ocean with relatively high frequency.