Introduction

Active Radar Sites:

As part of the Office of Naval Research-sponsored SouthEast Atlantic Coastal Ocean Observing System (SEACOOS), High Frequency (HF) Radars were deployed in four differing venues over the five years of the program (Figure 1). These HF radar systems used either direction-finding (Coastal Ocean Dynamics Application Radar SeaSonde: SS) or beam-forming techniques (Wellen Radar: WERA) to acquire radial currents from the Bragg peaks in the Doppler spectra. By mapping the radial current structure from at least two stations, the vector surface velocity fields were mapped in near real-time along sections of the continental shelves of North Carolina, South Carolina and Georgia, Southeast Florida Coast and the West Florida Shelf.  One of the programmatic goals focused on testing the latest technologies to acquire data from both long-range (lower-resolution) and medium range (higher-resolution) HF radars using both systems. The experimental program sought to exploit other measurement capabilities such as surface waves (both significant wave heights and directional wave spectra) as well as surface wind direction.

Figure 1: HF radar deployments (and radial coverage) with surface current vectors in April 2007 (EFS and MAB) and Oct 2007 (WFS) in the SEACOOS domain relative to bottom terrain in the SECOORA and GCOOS-RA footprint.

One of the concepts introduced in this program was the development of HF radar testbeds where sensors and instruments could be tested.  For example, during the summer of 2003, a dual-station WERA system was deployed along the West Florida Shelf overlooking acoustic Doppler current profilers (ADCP) moorings deployed within the University of South Florida Coastal Ocean Modeling and Prediction System (COMPS). These cross-shelf arrays provided an opportunity to assess WERA-derived surface currents over these moorings where the uppermost bin was located at ~4-m depth. In 2005, a “mini-waves” experiment was conducted where tri-axial surface wave instruments (courtesy of National Data Buoy Center and Georgia Institute of Technology) and bottom-mount acoustic profilers were deployed on two moorings over a two-month period in assessing WERA-derived wave measurements within the Florida Straits. The results indicated fairly good agreement between the buoy and WERA-derived significant wave heights and directional wave spectra using algorithms developed by Wyatt et al. (2003). Another important aspect of the SEACOOS HF radar undertaking was a link to the data management activity.  The interaction permitted the near real-time aggregation and visualization of the current observations from the HF radar, in-situ ADCPs and drifters in the SEACOOS footprint and demonstrates the feasibility of sharing the observations with the community of interested users.

Group and
Radar Type
Station Location Latitude (°N) Longitude (°W) Frequency (MHz)
USC/WERA Folly Beach, SC 32.65 -79.94 8.3
USC/WERA Prichard Island, SC 32.30 -80.51 8.3
SKIO/WERA St.Catherine, GA 31.69 -81.13 8.3
SKIO/WERA Jekyll Island, GA 31.06 -81.41 8.3
UM/WERA Dania Beach,FL 26.08 -80.12 16.0
UM/WERA Virginia Key, FL 25.74 -80.15 12.6
UM/WERA Crandon Park, FL 25.71 -80.15 16.0
UM/WERA Key Largo, FL 25.24 -80.31 16.0
UNC/SS Duck, NC 36.18 -75.75 5.0
UNC/SS Cape Hatteras, NC 35.26 -75.52 5.0
USF-COMPS/SS Rd. Shores, FL 27.83 -82.83 5.0
Mote/Rutgers/SS Venice, FL 27.08 -82.45 5.0
USF-COMPS/SS Naples FL 26.16 -81.81 5.0
USF-COMPS/  WERA Ft. DeSoto Park, FL 25.54 -82.72 12.6.
USF-COMPS/  WERA Venice, FL 27.07 -82.45 12.6
FAU/SS Hillsborough Inlet, FL 26.26 -80.12 25.
FAU/SS Haulover,  FL 25.90 -80.12 25.
USM/SS Destin, FL 30.29 -86.25 5.

Table 1: HF radars currently (or in the process) of being deployed in the SECOORA domain with their respective frequencies where USC: University of South Carolina, SKIO: Skidaway Institute of Oceanography, UM: University of Miami, USF: University of South Florida, FAU: Florida Atlantic University: MOTE: MOTE Marine Lab (Rutgers). USM: University of Southern Mississippi (GCOOS): SS: Seasonde, WERA: Wellen radar and COMPS: Coastal Ocean Mesoscale Prediction System (USF).

HF Radar Gap Analysis:

The objective of this document is to provide a gap analysis for SECOORA and link directly to GCOOS-RA along the west Florida Shelf and MACOORA to the northeast. A key aspect will be to outline a challenge we face in the southeast and GOM states (hurricanes), and the large dynamic ranges of the currents due to Loop Current, Florida Current and the Gulf Stream. Our approach uses the qualities of both WERA and SS to maximize the utility of surface current radars. Recent investigations have pointed to the use of such devices to map surface winds, which is an area of active research. In this context, our lessons learned from both systems are included. Potential users would like concurrent directional wave measurements that can only be achieved only with beam-forming technology. In discussion with forecasters at the National Weather Service in Miami forecasting Office, they want to these types of realtime measurements in the Florida Current where wave states significantly differ between the coastal and offshore regimes for daily forecasting. This is critical to the commercial and recreational boating communities.

As per Figure 2, we need to procure hardware and install 27 HF radar sites from North Carolina to the panhandle of Florida. We have provided the possible pecking order in how these sites should be deployed over the 20-10-2014 time frame with an emphasis of filling large gaps (i.e. between  North Carolina and South Carolina and Georgia and South Florida, and from Tampa to Pensacola . With these latter sites we intend on working with our GCOOS-RA colleagues in developing the network. Sharing expertise and experiences will be advantageous to both regional associations which is central to the IOOS theme.

Figure 2: Deployed and planned high frequency radars with differing frequencies from years 2010-2014 including the Insets that represent HF radar testbeds developed along the east and west Florida Shelves where the dynamical range of the currents and the forcing mechanisms is large.

Research Group Station ID Latitude (°N) Longitude (°W) Frequency (MHz) Yr
UNC South Cape Hatteras, NC 35.23 -75.65 6-12 2
UNC Cape Lookout, NC 34.75 -76.40 6-12 1
UNC Pine Knoll Shores, NC 34.68 -76.80 6-12 5
UNC Surf City, NC 34.40 -77.60 6-12 3
UNC Oak Island, NC 33.92 -78.13 6-12 4
USC North Myrtle Beach, SC     33.82 -78.68 6-12 3
USC Murrells Inlet, SC     33.55 -79.05 6-12 2
USC Cape Romain, SC 33.00 -79.45 6-12 1
SKIO Amelia Island, FL 30.62 -81.45 6-12 2
UNF Ponte Vedra, FL 30.14 -81.38 6-12 1
UNF Marineland, FL 29.66 -81.15 6-12 2
FIT New Smyrna Beach, FL 29.05 -80.92 6-12 1
FIT Cape Canaveral, FL 28.50 -80.60 6-12 1
FIT Melbourne, FL 28.12 -80.63 6-12 3
UM Vero Beach, FL 27.64 -80.39 6-12 4
UM Hobe Sound, FL 27.08 -80.14 6-12 4
UM Palm Beach, FL 26.65 -80.02 6-12 5
UM Upper Matacumbe, FL 24.90 -80.55 6-12 1
UM Marathon, FL 24.73 -81.00 6-12 2
UM Big Pine Key, FL 24.62 -81.36 6-12 3
UM Marquessas Key, FL 24.56 -82.12 6-12 4
UM Everglades Park, FL 25.24 -81.16 6-12 5
USF Duck Rock, FL      25.71 -81.30 6-12 3
USF Sanibel Island, FL 26.46 -82.17 6-12 2
USF Coon Key, FL 28.51 -82.70 6-12 3
USF Cedar Key, Fl 29.43 -83.30 6-12 4
USF Horsebeach, FL 29.80 -83.75 6-12 4
FSU St Marks, FL 29.78 -84.65 6-12 3
FSU Alligator Pt, FL 29.90 -84.35 6-12 4
FSU Cape St George, FL 29.59 -85.05 6-12 4
FSU St Andrew Sound, FL 30.10 -85.75 6-12 2
FSU/USM Pensacola, FL 30.35 -87.25 6-12 ?

Table 2: Planned HF radar stations to fill gaps in the SECOORA (GCOOS-RA) footprint with approximate positions, year of deployment where 1: 2010, 2:2011; 3:2012,4:2013 and 5: 2014 with the research group that oversees the sites UNC: University of North Carolina; USC: University of South Carolina; SKIO: Skidaway Institute of Oceanography; UNF: University of North Florida; FIT: Florida Institute of Technology; UM: University of Miami; USF: University of South Florida; and FSU: Florida State University. The total number of new stations is 27 for SECOORA from North Carolina to the Florida Panhandle. From Coon Key to St Andrew Sound, these FSU sites would be supported with GCOOS-RA.

The total number of new station and staffing are summarized in Table 3 from 2010-2014 for research groups in the footprint. The total number of new stations is 27 (with an additional four radars sponsored by GCOOS-RA at FSU and a radar at Pensacola). This totals thirty one radars spanning from North Carolina to the Florida Panhandle without the additional VHF radars for ports and harbors.

Research Group 2010 2011 2012 2013 2014 Total (new)
UNC 1 1 1 1 1 5
USC 1 1 1 0 0 3
SKIO 0 1 0 0 0 1
UNF 1 1 0 0 0 2
FIT 2 0 1 0 0 3
UM/EFS 0 0 0 2 1 3
UM/FL Keys 1 1 1 1 0 4
USF 0 1 2 2 1 6
Total 6 6 6 6 3 27
FSU/GCOOS 0 1 1 2 1 5/32

Table 3: Planned new stations from 2010 to 2014 in the SECOORA footprint for the long-range systems using one technician for every two sites. We have included a maximum of six stations per year over the region in the budget.

The Very High Frequency (VHF) radars around ports and harbors surrounding the coastline of SECOORA. As shown in Figure 3, ports staring at Wilmington to Tampa are shown. Given the eight harbors with two VHF radars per, this equates to 16 VHF radar stations. Given the shorter baseline distances, deployment costs tend to be less than for the longer range HF radars because of the reduced travel time (closer spacing) and the logistics is a bit easier A breakdown is given in Table 5. We envision one VHF radar technician per port given its import to ship traffic in and out of major ports.

 

Figure 3: Major ports in the SECOORA footprint that require VHF radar units with ranges of about 20 km and high spatial and temporal resolution transmitting at frequencies greater than 45 MHz with more than 2 MHz of bandwidth.