West Florida Shelf Circulation on Synoptic, Seasonal, and Interannual Time Scales

2013 ◽  
pp. 325-347 ◽  
Author(s):  
Robert H. Weisberg ◽  
Ruoying He ◽  
Yonggang Liu ◽  
Jyotika I. Virmani
Keyword(s):  
Time Scales ◽  
West Florida Shelf ◽  
Florida Shelf ◽  
Shelf Circulation

scholarly journals Ocean Currents and Sea Surface Heights Estimated across the West Florida Shelf

2007 ◽  
Vol 37 (6) ◽  
pp. 1697-1713 ◽  
Author(s):  
Yonggang Liu ◽  
Robert H. Weisberg
Keyword(s):  
Sea Level ◽  
Time Scales ◽  
Satellite Altimetry ◽  
Sea Surface ◽  
West Florida Shelf ◽  
The West ◽  
Inner Shelf ◽  
Florida Shelf ◽  
Synoptic Weather ◽  
Coastal Sea

Abstract The across-shelf structures of the ocean circulation and the associated sea surface height (SSH) variability are examined on the west Florida shelf (WFS) for the 3-yr interval from September 1998 to December 2001. Five sets of characteristic circulation patterns are extracted from 2-day, low-pass-filtered data using the self-organizing map: extreme upwelling and downwelling structures with strong currents, asymmetric upwelling and downwelling structures with moderate currents, and a set of transitional structures with weak currents. The temporal variations of these structures are coherent with the local winds on synoptic weather time scales. On seasonal time scales they are related to both the local winds and the water density variations. The circulation is predominantly upwelling during autumn to spring months (October–April) and downwelling during summer months (June–September). Coastal sea level fluctuations are related to both the dynamical responses of the inner shelf circulation to meteorological forcing and the offshore SSH. On long time scales, the offshore SSH variations appear to dominate, whereas on synoptic weather time scales, the inner shelf wind-driven circulation responses are largest. The across-shelf distribution of SSH is estimated from the velocity, hydrography, wind, and coastal sea level data, and the results are compared with satellite altimetry data, thereby providing a means for calibrating satellite altimetry on the shelf.

scholarly journals An Assessment of the Importance of Chaotic Stirring and Turbulent Mixing on the West Florida Shelf

2009 ◽  
Vol 39 (7) ◽  
pp. 1743-1755 ◽  
Author(s):  
F. J. Beron-Vera ◽  
M. J. Olascoaga
Keyword(s):  
Velocity Field ◽  
Time Scales ◽  
Turbulent Mixing ◽  
Large Scale ◽  
Ocean Model ◽  
Particle Dispersion ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf ◽  
Surface Ocean

Abstract Application of dynamical systems tools has recently revealed in surface ocean currents produced by a Hybrid-Coordinate Ocean Model (HYCOM) simulation the presence of a persistent large-scale Lagrangian coherent structure (LCS) on the southern portion of the west Florida shelf (WFS). Consistent with satellite-tracked drifter trajectories, this LCS constitutes a cross-shelf barrier for the lateral transport of passive tracers. Because of the constraints that the above LCS, as well as smaller-scale LCSs lying shoreside, can impose on pollutant dispersal and its potentially very important biological consequences, a study was carried out on the nature of the surface ocean Lagrangian motion on the WFS. The analysis is based on the same simulated surface ocean velocity field that has been able to sustain the aforementioned persistent cross-shelf transport barrier. Examination of several diagnostics suggests that chaotic stirring dominates over turbulent mixing on time scales of up to two months or so. More specifically, it is found on those time scales that tracer evolution at a given length scale is governed to a nonnegligible extent by coarser-scale velocity field features, fluid particle dispersion is spatially inhomogeneous, and the Lagrangian evolution is more irregular than the driving Eulerian flow.

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

High-Frequency Radar Mapping of Surface Currents Using WERA

2007 ◽  
Vol 24 (3) ◽  
pp. 484-503 ◽  
Author(s):  
Lynn K. Shay ◽  
Jorge Martinez-Pedraja ◽  
Thomas M. Cook ◽  
Brian K. Haus ◽  
Robert H. Weisberg
Keyword(s):  
Time Series ◽  
High Frequency ◽  
Tidal Currents ◽  
Tropical Storm ◽  
Surface Velocity ◽  
Surface Currents ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf ◽  
East West

Abstract A dual-station high-frequency Wellen Radar (WERA), transmitting at 16.045 MHz, was deployed along the west Florida shelf in phased array mode during the summer of 2003. A 33-day, continuous time series of radial and vector surface current fields was acquired starting on 23 August ending 25 September 2003. Over a 30-min sample interval, WERA mapped coastal ocean currents over an ≈40 km × 80 km footprint with a 1.2-km horizontal resolution. A total of 1628 snapshots of the vector surface currents was acquired, with only 70 samples (4.3%) missing from the vector time series. Comparisons to subsurface measurements from two moored acoustic Doppler current profilers revealed RMS differences of 1 to 5 cm s−1 for both radial and Cartesian current components. Regression analyses indicated slopes close to unity with small biases between surface and subsurface measurements at 4-m depth in the east–west (u) and north–south (υ) components, respectively. Vector correlation coefficients were 0.9 with complex phases of −3° and 5° at EC4 (20-m isobath) and NA2 (25-m isobath) moorings, respectively. Complex surface circulation patterns were observed that included tidal and wind-driven currents over the west Florida shelf. Tidal current amplitudes were 4 to 5 cm s−1 for the diurnal and semidiurnal constituents. Vertical structure of these tidal currents indicated that the semidiurnal components were predominantly barotropic whereas diurnal tidal currents had more of a baroclinic component. Tidal currents were removed from the observed current time series and were compared to the 10-m adjusted winds at a surface mooring. Based on these time series comparisons, regression slopes were 0.02 to 0.03 in the east–west and north–south directions, respectively. During Tropical Storm Henri’s passage on 5 September 2003, cyclonically rotating surface winds forced surface velocities of more than 35 cm s−1 as Henri made landfall north of Tampa Bay, Florida. These results suggest that the WERA measured the surface velocity well under weak to tropical storm wind conditions.

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