A comparison of near-surface current measurements by ADCP and HF-radar on the West Florida shelf

2004 ◽  
Author(s):  
F.J. Kelly ◽  
J.S. Bonner ◽  
J.C. Perez ◽  
D. Trujillo ◽  
R.H. Weisbere ◽  
...  
Keyword(s):  
Surface Current ◽  
Hf Radar ◽  
West Florida Shelf ◽  
The West ◽  
Near Surface ◽  
Florida Shelf

scholarly journals HF Radar Performance in a Low-Energy Environment: CODAR SeaSonde Experience on the West Florida Shelf*

2010 ◽  
Vol 27 (10) ◽  
pp. 1689-1710 ◽  
Author(s):  
Yonggang Liu ◽  
Robert H. Weisberg ◽  
Clifford R. Merz ◽  
Sage Lichtenwalner ◽  
Gary J. Kirkpatrick
Keyword(s):  
Coastal Ocean ◽  
Low Energy ◽  
Ocean Dynamics ◽  
Hf Radar ◽  
Limiting Factors ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf ◽  
Significant Wave ◽  
Energy Environment

Abstract Three long-range (5 MHz) Coastal Ocean Dynamics Application Radar (CODAR) SeaSonde HF radars overlooking an array of as many as eight moored acoustic Doppler current profilers (ADCPs) have operated on the West Florida Shelf since September 2003 for the purpose of observing the coastal ocean currents. HF radar performance on this low-energy (currents and waves) continental shelf is evaluated with respect to data returns, the rms differences between the HF radar and the ADCP radial currents, bearing offsets, and radial velocity uncertainties. Possible environmental factors affecting the HF radar performance are discussed, with the findings that both the low-energy sea state and the unfavorable surface wave directions are the main limiting factors for these HF radar observations of currents on the WFS. Despite the challenge of achieving continuous backscatter from this low-energy environment, when acquired the data quality is good in comparison with the ADCP measurements. The rms differences range from 6 to 10 cm s−1 for hourly and from 3 to 6 cm s−1 for 36-h low-pass-filtered radial currents, respectively. Bearing offsets are in the range from −15° to +9°. Coherent variations of the HF radar and ADCP radial currents are seen across both tidal and subtidal frequency bands. By examining the HF radar radial velocities at low wave energy, it is found that the data returns decrease rapidly for significant wave heights smaller than 1 m, and that the rms differences between the HF radar and ADCP radials are degraded when the significant wave height is smaller than 0.3 m.

Comparison of the X-TRACK altimetry estimated currents with moored ADCP and HF radar observations on the West Florida Shelf

2012 ◽  
Vol 50 (8) ◽  
pp. 1085-1098 ◽  
Author(s):  
Yonggang Liu ◽  
Robert H. Weisberg ◽  
Stefano Vignudelli ◽  
Laurent Roblou ◽  
Clifford R. Merz
Keyword(s):  
Hf Radar ◽  
West Florida Shelf ◽  
The West ◽  
Radar Observations ◽  
Florida Shelf

scholarly journals Current Patterns on the West Florida Shelf from Joint Self-Organizing Map Analyses of HF Radar and ADCP Data

2007 ◽  
Vol 24 (4) ◽  
pp. 702-712 ◽  
Author(s):  
Yonggang Liu ◽  
Robert H. Weisberg ◽  
Lynn K. Shay
Keyword(s):  
Hf Radar ◽  
Ocean Current ◽  
Self Organizing Map ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf ◽  
Buoyancy Forcing ◽  
Temporal Structures ◽  
Self Organizing

Abstract To assess the spatial structures and temporal evolutions of distinct physical processes on the West Florida Shelf, patterns of ocean current variability are extracted from a joint HF radar and ADCP dataset acquired from August to September 2003 using Self-Organizing Map (SOM) analyses. Three separate ocean–atmosphere frequency bands are considered: semidiurnal, diurnal, and subtidal. The currents in the semidiurnal band are relatively homogeneous in space, barotropic, clockwise polarized, and have a neap-spring modulation consistent with semidiurnal tides. The currents in the diurnal band are less homogeneous, more baroclinic, and clockwise polarized, consistent with a combination of diurnal tides and near-inertial oscillations. The currents in the subtidal frequency band are stronger and with more complex patterns consistent with wind and buoyancy forcing. The SOM is shown to be a useful technique for extracting ocean current patterns with dynamically distinctive spatial and temporal structures sampled by HF radar and supporting in situ measurements.

scholarly journals Assessment of CODAR SeaSonde and WERA HF Radars in Mapping Surface Currents on the West Florida Shelf*

2014 ◽  
Vol 31 (6) ◽  
pp. 1363-1382 ◽  
Author(s):  
Yonggang Liu ◽  
Robert H. Weisberg ◽  
Clifford R. Merz
Keyword(s):  
Radial Velocity ◽  
Long Range ◽  
Hf Radar ◽  
Integration Time ◽  
Surface Currents ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf ◽  
Radar Systems ◽  
Effective Depth

Abstract Concurrently operated on the West Florida shelf for the purpose of observing surface currents are three long-range (4.9 MHz) Coastal Ocean Dynamics Applications Radar (CODAR) SeaSonde and two median-range (12.7 MHz) Wellen Radar (WERA) high-frequency (HF) radar systems. These HF radars overlook an array of moored acoustic Doppler current profilers (ADCPs), three of which are presently within the radar footprint. Analyzed herein are 3 months of simultaneous observations. Both the SeaSonde and WERA systems generally agree with the ADCPs to within root-mean-square differences (rmsd) for hourly radial velocity components of 5.1–9.2 and 3.8–6.5 cm s−1 for SeaSonde and WERA, respectively, and within rmsd for 36-h low-pass filtered radial velocity components of 2.8–6.0 and 2.2–4.3 cm s−1 for SeaSonde and WERA, respectively. The bearing offset and tidal and subtidal currents of total velocities are also assessed using the ADCP data. Despite differences in a variety of aspects between the direction-finding CODAR SeaSonde (long range, effective depth of 2.4 m, integration time of 4 h, and idealized antenna patterns) and the beam-forming WERA (median range, effective depth of 0.9 m, and integration time of 1 h), both HF radar systems demonstrated good surface current mapping capability. The differences between the velocities measured with the HF radar and the ADCP are sufficiently small in this low-energy shelf that much of these rmsd values may be accounted for by the expected measurement differences due to the horizontal, vertical, and temporal sampling differences of the ocean current observing systems used.

High Frequency Radar Observing Systems in SEACOOS: 2002-2007 Lessons Learned

2008 ◽  
Vol 42 (3) ◽  
pp. 55-67 ◽  
Author(s):  
Lynn K. Shay ◽  
Harvey E. Seim ◽  
Dana Savidge ◽  
Richard Styles ◽  
Robert H. Weisberg
Keyword(s):  
North Carolina ◽  
High Frequency ◽  
Surface Current ◽  
Coastal Ocean ◽  
Quality Data ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf ◽  
The North ◽  
Wave Measurements

From 2002-2007, the Southeast Coastal Ocean Observing System (SEACOOS) deployed high frequency (HF) radars to overlook several venues stretching from the West Florida Shelf to the North Carolina Shelf. Based on extensive deliberations within SEACOOS, we decided to assess the two differing types of coastal ocean current radars within the southeast that were on the commercial market. The long-range SeaSondes (SS) were deployed to sense surface currents at hourly intervals and a 6 km resolution along the West Florida Shelf and the North Carolina Shelf. The medium and long-range Wellen Radars (WERA) were deployed along the Florida Straits and along the South Atlantic Bight with spatial resolutions of 1.2 to 3 km sampling at time scales of minutes. A common theme in these deployments was to sense the Loop Current, Florida Current and the Gulf Stream, which transport heat poleward as part of the gyre circulation.Several lessons were learned as part of these deployments, such as the need to protect against lightening strikes and the challenge of providing robust communication links between the remote sites and a central hub to make the data available in near real-time. Since states in the southeast and surrounding the Gulf of Mexico are prone to the passage of hurricanes, surface current and wave measurements during hurricanes are invaluable for improving storm surge and inundation models that are now being coupled to surface waves. In addition, significant wave heights (and directional surface wave spectra) are critical in the model assessment. Data quality and accuracy of the surface current and wave fields remain a central issue to search and rescue and safe maritime operations and to understanding the limitations of these radar systems. As more phased array systems (i.e., WERAs) are deployed for surface current and wave measurements, more attention needs to be placed on the interoperability between the two types of systems to insure the highest quality data possible is available to meet applied and operational goals. To insure the highest quality data possible, a full-time technician and a half-time IT specialist are needed for each installation as well as access to spares to keep these systems running consistently and to make quality observations available in near real-time.

An HF-radar test deployment amidst an ADCP array on the West Florida Shelf

2004 ◽  
Author(s):  
F.J. Kelly ◽  
J.S. Bonner ◽  
J.C. Perez ◽  
J.S. Adams ◽  
D. Prouty ◽  
...  
Keyword(s):  
Hf Radar ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf

scholarly journals Velocity Comparisons from Upward and Downward Acoustic Doppler Current Profilers on the West Florida Shelf

2007 ◽  
Vol 24 (11) ◽  
pp. 1950-1960 ◽  
Author(s):  
Dennis A. Mayer ◽  
Jyotika I. Virmani ◽  
Robert H. Weisberg
Keyword(s):  
Water Column ◽  
Regional Differences ◽  
Wave Activity ◽  
West Florida Shelf ◽  
The West ◽  
Near Surface ◽  
Florida Shelf ◽  
Acoustic Doppler Current Profilers ◽  
Surface Observations ◽  
Good Agreement

Abstract Current observations are compared from upward- and downward-looking acoustic Doppler current profilers (ADCPs) deployed on the West Florida Shelf (WFS). Despite regional differences, statistical analyses show good agreement between all sets of observations throughout the water column except in the upper few meters where all downward-looking ADCPs exhibit small, but significant, reduction in rms speed values. Evidence suggests that this reduction is mooring related. It is possible that the presence of near-surface bubbles caused by wave activity could bias the near-surface observations. Otherwise, either the upward- or downward-looking mooring systems produce equivalent observations with differences due to spatial variations.

USGS field activity 09FSH02 on the west Florida shelf, Gulf of Mexico, in August 2009

Data Series ◽  
2009 ◽  
Author(s):  
Lisa L. Robbins ◽  
Paul O. Knorr ◽  
Xuewu Liu ◽  
Robert H. Byrne ◽  
Ellen A. Raabe
Keyword(s):  
Gulf Of Mexico ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf ◽  
Field Activity

USGS Field Activities 11CEV01 and 11CEV02 on the West Florida Shelf, Gulf of Mexico, in January and February 2011

Data Series ◽  
10.3133/ds711 ◽  
2014 ◽  
Author(s):  
Lisa L. Robbins ◽  
Paul O. Knorr ◽  
Kendra L. Daly ◽  
Carl A. Taylor
Keyword(s):  
Gulf Of Mexico ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf
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