Long-Term Analysis of Gulf Stream Variability at Cape Hatteras Using High-Frequency Radar Surface Current Observations

Long-range high-frequency radar observations collected offshore of Cape Hatteras, North Carolina, can play a pivotal role in monitoring the Gulf Stream (GS) separation point and orientation angle. We present an analysis of the long-term variation of the GS, using radar-measured ocean surface currents for 18 years at three coastal sites: Duck, Buxton, and the Core Banks of NC (DUCK, HATY, CORE). This is the first measurement program to obtain an hourly, high-resolution GS time history spanning decades, documenting the spatial and temporal variability of the GS at various time scales. A consistent database has been created by reprocessing all existing radar observations from these sites. We here focus on monthly and longer temporal variability, utilizing the month-averaged radial component of surface velocity to extract the Gulf Stream’s separation location, path, and speed. Using high-frequency data spanning nearly two decades, this study demonstrates the GS’s long-term variability, particularly in relation to climate-driven changes, including shifts in ocean circulation, and coastal sea level rise. Our analysis reveals significant offshore and nearshore shifts in GS position, with major offshore displacements observed in 2010 and 2019. Additionally, changes in orientation angle, especially near Cape Hatteras, suggest variations of GS transport, which have implications for regional sea levels and coastal ecosystems. These findings highlight the importance of long-term monitoring for assessing the resilience of North Carolina’s coastal ecosystems to ongoing climatic changes.

Presentation Preference: Oral

Primary Presenter: Yubeen Jeong, University of North Carolina - Chapel Hill (ybjeong@unc.edu)

Authors:

Yubeen Jeong, University of North Carolina at Chapel Hill  (ybjeong@unc.edu)

Harvey Seim, University of North Carolina at Chapel Hill  (hseim@email.unc.edu)

John Bane, University of North Carolina at Chapel Hill  (bane@unc.edu)

Magdalena Andres, Woods Hole Oceanographic Institution  (mandres@whoi.edu)

Mike Muglia, East Carolina University, Coastal Studies Institute  (muglia@gmail.com)

Caroline Lowcher, East Carolina University, Coastal Studies Institute  (clowch531@gmail.com)

Trip Taylor, East Carolina University, Coastal Studies Institute  (patterson.taylor.iii@gmail.com)