Inferring Florida Current Volume Transport From Satellite Altimetry

2020 ◽  
Vol 125 (12) ◽  
Author(s):  
Denis L. Volkov ◽  
Ricardo Domingues ◽  
Christopher S. Meinen ◽  
Rigoberto Garcia ◽  
Molly Baringer ◽  
...  
Keyword(s):  
Satellite Altimetry ◽  
Volume Transport ◽  
Florida Current ◽  
Current Volume

Inferring Florida Current volume transport from satellite altimetry

2020 ◽  
Author(s):  
Denis L. Volkov ◽  
Ricardo M. Domingues ◽  
Christopher S. Meinen ◽  
Rigoberto F. Garcia ◽  
Molly O'Neill Baringer ◽  
...  
Keyword(s):  
Satellite Altimetry ◽  
Volume Transport ◽  
Florida Current ◽  
Current Volume

scholarly journals Malvinas Current Volume Transport at 41°S: A 24 Yearlong Time Series Consistent With Mooring Data From 3 Decades and Satellite Altimetry

2018 ◽  
Vol 123 (1) ◽  
pp. 378-398 ◽  
Author(s):  
Camila Artana ◽  
Ramiro Ferrari ◽  
Zoé Koenig ◽  
Nathalie Sennéchael ◽  
Martin Saraceno ◽  
...  
Keyword(s):  
Time Series ◽  
Satellite Altimetry ◽  
Volume Transport ◽  
Current Volume

scholarly journals Overflow of cold water across the Iceland-Faroe Ridge through the Western Valley

2018 ◽  
Author(s):  
Bogi Hansen ◽  
Karin Margretha Húsgarð Larsen ◽  
Steffen Malskær Olsen ◽  
Detlef Quadfasel ◽  
Kerstin Jochumsen ◽  
...  
Keyword(s):  
Satellite Altimetry ◽  
Cold Water ◽  
Large Fraction ◽  
Acoustic Doppler Current Profiler ◽  
Atlantic Water ◽  
Volume Transport ◽  
Meridional Overturning Circulation ◽  
Direct Measurements ◽  
Current Profiler ◽  
Meridional Overturning

Abstract. The Iceland-Faroe Ridge (IFR) is considered to be the third-most important passage for dense overflow water from the Nordic Seas feeding into the lower limb of the Atlantic Meridional Overturning Circulation with a volume transport on the order of 1 Sv (106 m3 s−1). The Western Valley, which is the northernmost deep passage across the IFR, has been presumed to supply a strong and persistent overflow (WV-overflow), contributing a large fraction of the total overflow across the IFR. However, prolonged measurements of this transport are so far missing. In order to quantify the flow by direct measurements, three instrumental packages were deployed close to the sill of the Western Valley for 278 days (2016–2017) including an Acoustic Doppler Current Profiler at the expected location of the overflow core. The average volume transport of WV-overflow during this field experiment was found to be less than 0.03 Sv. Aided by the observations and a two-layer hydraulic model, we argue that the reason for this low value is the inflow of warm Atlantic Water to the Norwegian Sea in the upper layers suppressing the deep overflow. The link between deep and surface flows explains an observed relationship between overflow and sea level slope as measured by satellite altimetry. This relationship, combined with historical hydrographic measurements allows us to conclude that the volume transport of WV-overflow most likely has been less than 0.1 Sv on average since the beginning of regular satellite altimetry in 1993. Our new direct measurements do not allow us to present an updated estimate of the total overflow across the IFR, but they indicate that it may well be considerably less than 1 Sv.

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 Brazil Current volume transport variability during 2009‐2015 from a long‐term moored array at 34.5°S

2021 ◽  
Author(s):  
M. P. Chidichimo ◽  
A. R. Piola ◽  
C. S. Meinen ◽  
R. C. Perez ◽  
E. J. D. Campos ◽  
...  
Keyword(s):  
Volume Transport ◽  
Current Volume ◽  
Brazil Current

Pathways connecting the North Brazil Current and the RAPID line

2021 ◽  
Author(s):  
Kimberley Drouin ◽  
M Susan Lozier ◽  
F Javier Beron-Vera ◽  
Phillip Miron ◽  
M Josefina Olascoaga
Keyword(s):  
Three Dimensional ◽  
Volume Transport ◽  
Florida Current ◽  
The North ◽  
Dynamical Systems Analysis ◽  
Brazil Current ◽  
North Brazil ◽  
North Brazil Current ◽  
The Caribbean ◽  
Surface Drifters

<p>The North Brazil Current is considered a bottleneck in the South Atlantic, responsible for funneling upper-ocean waters into the North Atlantic. This work explores the surface and subsurface pathways that connect the North Brazil Current to the RAPID line. To that extent, observational trajectories from surface drifters and Argo floats are used in conjunction with Markov chain theory and tools from dynamical systems analysis to compute probable pathways. More specifically, these pathways are computed as ensembles of paths transitioning directly between the North Brazil Current and the RAPID line. In addition, simulated trajectories will be used (1) to assess how representative the two-dimensional observational trajectories are of the three-dimensional circulation, and (2) to compute the associated volume transport of different pathways. Preliminary results suggest that two dominant pathways connect the North Brazil Current and the RAPID line. First, is the traditional pathway through the Caribbean Sea and Gulf of Mexico, which carries waters to the Florida Current, and second is a more direct route east of the Caribbean that supplies waters to the Antilles Current and the basin interior.  </p>

Long-term observations of the strongest inflow branch of warm water to the Arctic Mediterranean

2020 ◽  
Author(s):  
Bogi Hansen ◽  
Karin M. H. Larsen ◽  
Hjálmar Hátún ◽  
Svein Østerhus
Keyword(s):  
Satellite Altimetry ◽  
Saline Water ◽  
Accurate Determination ◽  
Volume Transport ◽  
High Accuracy ◽  
The Arctic ◽  
Boundary Current ◽  
Data Set

<p>Warm and saline water from the North Atlantic enters the Arctic Mediterranean through three gaps. The strongest of these three flows is the inflow between Iceland and Faroes, which is focused into a narrow boundary current north of the Faroes. This boundary current, the Faroe Current, has been observed with regular CTD cruises since 1988 and with moored ADCPs since 1997, as well as satellite altimetry since 1993. Once calibrated by the long-term ADCP measurements, the satellite altimetry is found to yield high-accuracy determination of the velocity field and volume transport down to fixed depth. Due to geostrophic adjustment, satellite altimetry combined with CTD data also allow fairly accurate determination of the depth of the Atlantic layer. From the combined data set, monthly transport time series have been generated for the period Jan 1993 to April 2019. Over the period, the annually averaged volume transport of Atlantic water in the Faroe Current seems to have increased slightly, while the heat transport relative to an outflow temperature of 0°C increased by 13%, significant at the 95% level. The salinity increased from the mid-1990s to around 2010, after which it has decreased, especially after 2016, leading to the lowest salinities in the whole period since 1988. To stay updated on a possible inflow reduction due to reduced thermohaline ventilation caused by this freshening, the future monitoring system of the Faroe Current is planned to be expanded with moored PIES (Pressure Inverted Echo Sounders). An experiment with two PIES in 2017-2019 has documented that these instruments allow high-accuracy monitoring of the depth of the Atlantic layer on the section, which combined with satellite altimetry and CTD observations should give more accurate transport estimates.</p>

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