This award is funded under the American Rescue Plan Act of 2021 (Public Law 117-2)<br/><br/>This project will use a number of existing data sources from the ocean and from the atmosphere to determine variations of the Gulf Stream near Cape Hatteras from 2004 to the present time. The Gulf Stream variations to be studied range in periodicity from a day or two to interannual. Possible causes of these variations will be determined utilizing measurements from the ocean and the atmosphere. This characterization of the Gulf Stream will provide a description of how the Gulf Stream affects and is affected by ocean and atmospheric circulations in the North Atlantic. The project will explore potential influences from climate variability as well as explore the feasibility of harnessing energy from the Gulf Stream off Cape Hatteras. The project will support one post-doctoral scholar, two graduate students and one undergraduate student in the pursuit of various project objectives. <br/><br/>The study will investigate the nature and causes of variability of the Gulf Stream near Cape Hatteras and explore how the Gulf Stream affects and is affected by oceanic and atmospheric processes in the North Atlantic. This will be done by reprocessing and analyzing HF radar surface current measurements and comparing these findings with ancillary data to test hypotheses about controls on and consequences of Gulf Stream variability. Analyses will consist of examining the position, path, structure, and location of separation of the Gulf Stream at temporal scales ranging from event-scale to interannual. The HF radar data will be compared to (i) in-situ and altimetry data, (ii) Oleander data, (iii) data from Line W of the Deep Western Boundary Current, (iv) data from the RAPID line, (v) cable data of transport at Florida Strait, and (vi) counts and trajectories of cold and warm core rings. Gulf Stream properties will also be compared to atmospheric forcing variability such as the NAO index, Jet Stream position, local wind stress, and basin-scale wind-stress curl. The project will derive Gulf Stream characteristics from observations collected since 2004 and result in a database updated in near real-time. Measurements with HF radar will continue after this project expires. Also, the project will provide information about the feasibility of harnessing energy from the Gulf Stream. The project will support one post-doctoral scholar, 2 graduate students and 1 undergraduate student.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.