Comparison of surface currents measured by HF Doppler radar in the western Florida Straits during November 1983 to January 1984 and Florida Current transports

1986 ◽  
Vol 91 (C7) ◽  
pp. 8451 ◽  
Author(s):  
Friedrich A. Schott ◽  
Shelby A. Frisch ◽  
Jimmy C. Larsen
Keyword(s):  
Doppler Radar ◽  
Surface Currents ◽  
Florida Current ◽  
Florida Straits

scholarly journals Interoperability of SeaSondes and Wellen Radars in Mapping Radial Surface Currents

2013 ◽  
Vol 30 (11) ◽  
pp. 2662-2675 ◽  
Author(s):  
J. Martinez-Pedraja ◽  
L. K. Shay ◽  
B. K. Haus ◽  
C. Whelan
Keyword(s):  
Acoustic Doppler Current Profiler ◽  
Hf Radar ◽  
Small Scale ◽  
Surface Currents ◽  
Florida Current ◽  
Current Profiler ◽  
Florida Straits ◽  
Subsurface Current ◽  
Geometric Dilution Of Precision ◽  
Good Agreement

Abstract A dual-station high-frequency (HF) Wellen Radar (WERA) transmitting at 16 MHz has observed near-real-time surface currents over an approximate range of 100 km across the Florida Straits since July 2004. During a 10-day period in April 2005 (15–25 April), a pair of 12.6-MHz SeaSondes (SS) were deployed south of the WERAs sites by NOAA's Center for Operational Oceanographic Products and Services (CO-OPS). The resulting SS grid overlapped the southern portion of the WERA domain. During the same period of time, a bottom-mounted acoustic Doppler current profiler (ADCP) acquired subsurface current measurements within these HF radar grids starting at 14 m below the surface in water of 86-m depth. The interoperability of beam-forming (WERA) and direction-finding (SS) HF radar technologies was examined. Comparisons of radial and vector currents for an 8-day concurrent time series suggested good agreement in current direction over both domains, where the surface currents' magnitudes were a maximum of 1.2 m s−1. In the core of the radar domains consisting of 108 cells, hourly vector currents were obtained by combining WERA and SS radials. Generally, this can be done in a relatively straightforward manner, considering the geometric dilution of precision (GDOP). A second key issue is downscaling the SS measurements from a 3-km grid to a 1.1-km grid to match the WERA output. This enhanced grid spacing is important along the western flank of the Florida Current, where energetic, small-scale surface features have been observed.

Accuracy of Florida Current Volume Transport Measurements at 27°N Using Multiple Observational Techniques

2014 ◽  
Vol 31 (5) ◽  
pp. 1169-1180 ◽  
Author(s):  
Rigoberto F. Garcia ◽  
Christopher S. Meinen
Keyword(s):  
Acoustic Doppler Current Profiler ◽  
Volume Transport ◽  
Florida Current ◽  
Absolute Accuracy ◽  
Submarine Cable ◽  
Accuracy And Precision ◽  
Transport Calculation ◽  
The Absolute ◽  
Florida Straits ◽  
Long Term Observation

AbstractFor more than 30 years, the volume transport of the Florida Current at 27°N has been regularly estimated both via voltage measurements on a submarine cable and using ship-based measurements of horizontal velocity at nine historical stations across the Florida Straits. A comparison of three different observational systems is presented, including a detailed evaluation of observational accuracy and precision. The three systems examined are dropsonde (free-falling float), lowered acoustic Doppler current profiler (LADCP), and submarine cable. The accuracy of the Florida Current transport calculation from dropsonde sections, which can be determined from first principles with existing data, is shown to be 0.8 Sv (1 Sv ≡ 106 m3 s−1). Side-by-side comparisons between dropsonde and LADCP measurements are used to show that the LADCP-based transport estimates are accurate to within 1.3 Sv. Dropsonde data are often used to set the absolute mean cable transport estimate, so some care is required in establishing the absolute accuracy of the cable measurements. Used together, the dropsonde and LADCP sections can be used to evaluate the absolute accuracy and precision of the cable measurements. These comparisons suggest the daily cable observations are accurate to within 1.7 Sv, and analysis of the decorrelation time scales for the errors suggests that annual transport averages from the cable are accurate to within 0.3 Sv. The implications of these accuracy estimates for long-term observation of the Florida Current are discussed in the context of maintaining this key climate record.

scholarly journals Observations of the Florida and Yucatan Currents from a Caribbean Cruise Ship

2010 ◽  
Vol 40 (7) ◽  
pp. 1575-1581 ◽  
Author(s):  
Clément Rousset ◽  
Lisa M. Beal
Keyword(s):  
North Atlantic ◽  
Thermohaline Circulation ◽  
North Atlantic Ocean ◽  
Florida Current ◽  
Cruise Ship ◽  
Velocity Data ◽  
The Mean ◽  
Return Path ◽  
Florida Straits ◽  
Yucatan Channel

Abstract The Yucatan and Florida Currents represent the majority of the warm-water return path of the global thermohaline circulation through the tropical/subtropical North Atlantic Ocean. Their transports are quantified and compared by analyzing velocity data collected aboard the cruise ship Explorer of the Seas. From 157 crossings between May 2001 and May 2006, the mean transport of the Florida Current at 26°N was estimated to be 30.8 ± 3.2 Sv (1 Sv ≡ 106 m3 s−1), with seasonal amplitude of 2.9 Sv. Upstream, the Yucatan Current was estimated from 90 crossings to be 30.3 ± 5 Sv, with seasonal amplitude of 2.7 Sv. These two currents are shown to be linked at seasonal time scales. Hence, contrary to former results, it was found that transports through the Florida Straits and the Yucatan Channel are similar, with the implication that only small inflows occur through minor channels between them.

The structure of ocean-surface currents measured by Doppler radar

1997 ◽  
Vol 22 (1) ◽  
pp. 156-167 ◽  
Author(s):  
D.A. Chin ◽  
S. Chinthamreddy ◽  
L.K. Shay ◽  
H.C. Graber
Keyword(s):  
Doppler Radar ◽  
Ocean Surface ◽  
Surface Currents ◽  
Ocean Surface Currents

scholarly journals Low-Frequency Surface Currents and Generation of an Island Lee Eddy in Panay Island, Philippines

2019 ◽  
Vol 49 (3) ◽  
pp. 765-787 ◽  
Author(s):  
Charina Lyn Amedo-Repollo ◽  
Xavier Flores-Vidal ◽  
Cedric Chavanne ◽  
Cesar L. Villanoy ◽  
Pierre Flament
Keyword(s):  
Wind Stress ◽  
Doppler Radar ◽  
Low Frequency ◽  
Acoustic Doppler Current Profiler ◽  
Cyclonic Eddy ◽  
Surface Currents ◽  
Wind Stress Curl ◽  
Near Surface ◽  
Geostrophic Balance ◽  
Mesoscale Currents

AbstractHigh-frequency Doppler radar (HFDR) and acoustic Doppler current profiler (ADCP) time-series observations during the Philippine Straits Dynamics Experiment (PhilEx) were analyzed to describe the mesoscale currents in Panay Strait, Philippines. Low-frequency surface currents inferred from three HFDR (July 2008–July 2009), reveal a clear seasonal signal concurrent with the reversal of the Asian monsoon. A mesoscale cyclonic eddy west of Panay Island is generated during the winter northeast (NE) monsoon. This causes changes in the strength, depth, and width of the intraseasonal Panay coastal (PC) jet as its eastern limb. Winds from QuikSCAT and from a nearby airport indicate that these flow structures correlate with the strength and direction of the prevailing local wind. An intensive survey in 8–9 February 2009 using 24 h of successive cross-shore conductivity–temperature–depth (CTD) sections, which in conjunction with shipboard ADCP measurements, show a well-developed cyclonic eddy characterized by near-surface velocities of 50 cm s−1. This eddy coincides with the intensification of the wind in between Mindoro and Panay Islands, generating a positive wind stress curl in the lee of Panay, which in turn induces divergent surface currents. Water column response from the mean transects show a pronounced signal of upwelling, indicated by the doming of isotherms and isopycnals. A pressure gradient then is set up, resulting in the spin up of a cyclonic eddy in geostrophic balance. Evolution of the vorticity within the vortex core confirms wind stress curl as the dominant forcing.

Longshore Surface Currents Measured by Doppler Radar and Video PIV Techniques

2009 ◽  
Vol 47 (8) ◽  
pp. 2787-2800 ◽  
Author(s):  
D. Perkovic ◽  
T.C. Lippmann ◽  
S.J. Frasier
Keyword(s):  
Doppler Radar ◽  
Surface Currents

scholarly journals Mechanisms of Eddy-Driven Variability of the Florida Current

2019 ◽  
Vol 49 (5) ◽  
pp. 1319-1338 ◽  
Author(s):  
Ricardo M. Domingues ◽  
William E. Johns ◽  
Christopher S. Meinen
Keyword(s):  
Open Ocean ◽  
Meridional Overturning Circulation ◽  
Western Boundary ◽  
Florida Current ◽  
Response Mechanism ◽  
Intrinsic Variability ◽  
Boundary Current ◽  
Indirect Response ◽  
Florida Straits ◽  
Anticyclonic Eddies

In this study, mechanisms causing year-to-year changes in the Florida Current seasonality are investigated using controlled realistic numerical experiments designed to isolate the western boundary responses to westward-propagating open ocean signals. The experiments reveal two distinct processes by which westward-propagating signals can modulate the phase of the Florida Current variability, which we refer to as the “direct” and “indirect” response mechanisms. The direct response mechanism involves a two-stage response to open ocean anticyclonic eddies characterized by the direct influence of Rossby wave barotropic anomalies and baroclinic wall jets that propagate through Northwest Providence Channel. In the indirect response mechanism, open ocean signals act as small perturbations to the stochastic Gulf Stream variability downstream, which are then transmitted upstream to the Florida Straits through baroclinic coastally trapped signals that can rapidly travel along the U.S. East Coast. Experiments indicate that westward-propagating eddies play a key role in modulating the phase of the Florida Current variability, but not the amplitude, which is determined by its intrinsic variability in our simulations. Results from this study further suggest that the Antilles Current may act as a semipermeable barrier to incoming signals, favoring the interaction through the indirect response mechanism. The mechanisms reported here can be potentially linked to year-to-year changes in the seasonality of the Atlantic meridional overturning circulation and may also be present in other western boundary current systems.

Icelandic Low and Azores High Migrations Impact Florida Current Transport in Winter

2021 ◽  
Author(s):  
Sultan Hameed ◽  
Christopher L. P. Wolfe ◽  
Lequan Chi
Keyword(s):  
Wind Stress ◽  
North Atlantic ◽  
Florida Current ◽  
Current Transport ◽  
Wind Stress Curl ◽  
Negative Results ◽  
The North ◽  
Icelandic Low ◽  
Florida Straits ◽  
Azores High

AbstractPrevious work to find an association between variations of annually averaged Florida Current transport and the North Atlantic Oscillation (NAO) have yielded negative results (Meinen et al. 2010). Here we show that Florida current in winter is impacted by displacements in the positions of the Azores High and the Icelandic Low, the constituent pressure centers of the NAO. As a one-dimensional representation of North Atlantic atmospheric circulation, the NAO index does not distinguish displacements of the pressure centers from fluctuations in their intensity. Florida Current transport is significantly correlated with Icelandic Low longitude with a lag of less than one season. We carried out perturbation experiments in the ECCOv4 model to investigate these correlations. These experiments reveal that east-west shifts of the Icelandic Low perturb the wind stress in mid-latitudes adjacent to the American coast, driving downwelling (through longshore winds) and offshore sea level anomalies (through wind stress curl) which travel to the Florida Straits within the same season. Florida Current transport is also correlated with the latitude variations of both the Icelandic Low and the Azores High with a lag of four years. Regression analysis shows that latitude variations of the Icelandic Low and the Azores High are associated with positive wind stress curl anomalies over extended regions in the ocean east of Florida. Rossby wave propagation from this region to the Florida Straits has been suggested as a mechanism for perturbing FCT transport in several previous studies (DiNezio et al. 2009; Czeschel et al. 2012; Frajka-Williams et al. 2013; Domingues et al. 2016, 2019).

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