Gulf Stream Position, Width, and Orientation Estimates with HF Radar off Cape Hatteras, N.C.

Mike Muglia1, Harvey Seim2 and Sara Haines2, (1)University of North Carolina Coastal Studies Insitute, Wanchese, NC, United States, (2)University of North Carolina at Chapel Hill, Marine Sciences, Chapel Hill, NC, United States
Abstract:
A method using radial velocity measurements from surface current-mapping High-Frequency Radars (HFRs) provides time-varying estimates of the landward Gulf Stream (GS) edge and jet axis locations, orientation, and width of the Cyclonic Shear Zone (CSZ) off Cape Hatteras, NC with daily temporal resolution. The method was developed using surface currents from November, 2014. Estimate qualities decreased with range from the radars. Cross-correlations between individual radar estimates in the same region vary from 0.61-0.82 for the GS edge location and 0.65-0.77 for the jet axis location. GS CSZ width metrics mean values vary from 29 to 32 km. Daily GS orientation estimates are least certain because they are affected by the crossing angle of the radial bearing relative to the GS. Lagged correlations between estimate sites suggest meander propagation speed estimates double from 2.88 km/hr south of the Cape Hatteras, to 5.69 km/hr just east of it.

The method is used to analyze GS variability during 2018 as part of the Processes Driving Exchange At Cape Hatteras (PEACH) program. GS properties derived from the HFR are compared with independent estimates to quantify GS variability during the project period. Preliminary results of the observed GS variability and its influence on shelf and deep ocean exchange off Cape Hatteras will be presented.