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Publications
Presentations, Posters, and Papers relating to HF Radar
- H. E. Seim, L. Stearns, University of North Carolina at Chapel Hill D. Barrick and B. Lipa, CODAR Ocean Sensors, Ltd. ; Characterization of Noise in HF Radar on the North Carolina Outer Banks, in Prep
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On the Outer Banks of North Carolina, the University of North Carolina at Chapel Hill operates a long range SeaSonde HF radar network to measure surface currents. Initially installed in the summer of 2003, the two site system has been quasi-operational since, but has encountered a range of challenges. One of these challenges is the often poor signal to noise ratio that leads to currents that are sometimes physically unrealistic. This is due in part to the unusually noisy local environment, but this problem has also highlighted some issues in the data processing algorithms. Long and short term noise characteristics will be examined in the raw spectral data in conjunction with related data quality issues. A two tiered approach is being implemented to address the problems with data quality: working with raw spectral data to ameliorate problems with the algorithms; as well as working with radial current component data to develop a badflagging scheme to identify inaccuracies. The relative successes of these two approaches will be compared by examining specific test cases using both methods, and recommendations will be made for dealing with this type of low signal to noise problem in software.
Presented at the 2006 Ocean Sciences Meeting in Honolulu, HI.
- Stearns, L.; Seim, H.E.; Muglia, M.; Measuring Surface Currents off the Outer Banks of North Carolina, ROW 5, Pescadero, California
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Beginning in early summer 2003 two Long Range SeaSonde HF Radar units
were deployed on the Outer Banks of North Carolina. This presentation
focuses
on the analysis of the data collected since that time. The challenge of
maintaining up-to-date antenna pattern measurements, and issues with
radio
noise will be explored. Variations in coverage over time and possible
causes
will be presented. Comparison with a four and a half month long ADCP
record of
current measurements indicates the importance of using measured beam
patterns.
The relationship between the strength and position of the Gulf Stream
and
currents on the continental shelf will be considered, as well as
preliminary
evidence for variations in the location of cross-shelf flow at the
shelf break.
The complete PPT presentation is available.
- Stearns, L.; Seim, H.E.; Muglia, M.; Bane, J.; Blanton, B.; HF Radar Measurements of Surface Currents off the Outer Banks of North Carolina, in Prep
-
Two HF Radar units were deployed on the Outer Banks of North Carolina
early in summer 2003, one at the Army Corps of Engineers Field Research
Facility in Duck; and one at the Cape Hatteras Coast Guard Facility in
Buxton. Both were Long Range SeaSonde units, manufactured by Codar
Ocean Sensors. This technology relies on ocean surface waves to scatter
HF radio waves, then uses Doppler shift and theoretical wave speed to
compute surface currents. Output from two sites results in a map of
surface currents that are an average over a 6 km by 6 km square of
ocean up to 200 km from the shore. These measurements are a temporal
average, outputting a three-hour average every hour in near-real time.
This technical report provides summary information on the radar deployment and data flow from installation through December 2004.
The complete draft PDF document is available.
- Stearns, L.; Seim, H.E.; Muglia, M.; Measuring Surface Currents off the Outer Banks of North Carolina, ROW 5, Pescadero, California
-
Beginning in early summer 2003 two Long Range SeaSonde HF Radar units
were deployed on the Outer Banks of North Carolina. This presentation
focuses
on the analysis of the data collected since that time. The challenge of
maintaining up-to-date antenna pattern measurements, and issues with
radio
noise will be explored. Variations in coverage over time and possible
causes
will be presented. Comparison with a four and a half month long ADCP
record of
current measurements indicates the importance of using measured beam
patterns.
The relationship between the strength and position of the Gulf Stream
and
currents on the continental shelf will be considered, as well as
preliminary
evidence for variations in the location of cross-shelf flow at the
shelf break.
The complete PPT presentation is available.
- Stearns, L.; Muglia, M.; Seim, H.E.; Bane, J.; Blanton, B.; Surface Currents off the Outer Banks of North Carolina, ROW 4, Magnetic Island, Queensland, Australia
-
This presentation focuses on the effects of using measured vs. ideal
antenna patterns, the physical configuration of the sites, mean
currents, and all available data comparissons. Tidal harmonic analyses
for all points of consistent coverage in the region are compared to
tidal model results. Also, since the region of data coverage often
includes part of the Gulf Stream, characteristics of its flow are
compared with thermal satelite imagery.
The complete PPT presentation is available.
- Stearns, L.; Muglia, M.; Seim, H.E.; Bane, J.; Surface Currents Off the Outer Banks of North Carolina, ASLO/TOS Ocean Research 2004 Conference, Honolulu, Hawaii
-
Beginning in early summer 2003 two HF Radar units were deployed on the
Outer Banks of North Carolina: at the Army Corps of Engineers Field
Research Facility in Duck; and at the Cape Hatteras Coast Guard
Facility in Buxton. Both were Long Range SeaSonde units, manufactured
by Codar Ocean Sensors. This component of the regional observing system
SEACOOS relies on ocean waves to scatter HF radio waves, then uses
Doppler shift and theoretical wave speed to compute surface currents.
Combining output from two sites results in a map of surface currents
that are an average over a 6 by 6 km square of ocean up to 120 km from
the shore. These measurements are a temporal average, outputting a
three hour average every hour in near real time.
Our analysis focuses on long term mean currents and tidal harmonic analyses for all points of consistent coverage in the region. Tidal ellipse parameters are compared to model results. Since the region of data coverage often includes part of the Gulf Stream, characteristics of its flow are compared with thermal imagery.
The complete PDF poster is available.