Surveying the Upper Ocean with the Ocean Surveyor: A New Phased Array Doppler Current Profiler

Fischer, Jürgen; Brandt, Peter; Dengler, Marcus; Müller, Mario; Symonds, Darryl

doi:10.1175/1520-0426(2003)20<742:stuowt>2.0.co;2

Cited by 34 publications

(25 citation statements)

References 11 publications

(8 reference statements)

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“…The mean velocity errors estimate using LDEO 7.0 software are, for most of the LADCP profiles, of the order of 2 cm s À1 , which is comparable with other results (Fischer et al, 2003). Error changes with depth; the bottom-tracked velocity has lower error than that measured near the surface (up to 5 cm s À1 ).…”

Section: Ladcp Resultssupporting

confidence: 83%

The West Spitsbergen Current volume and heat transport from synoptic observations in summer

Walczowski

Piechura

Osiński

et al. 2005

Deep Sea Research Part I: Oceanographic Research Papers

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This study describes the results of quasi-synoptic hydrographic observations of the West Spitsbergen Current made in summer 2003. Various sources of information and calculation methods were used to estimate the northward volume and heat transport. Ultimately, the results based on the Lowered Acoustic Doppler Current Profiled data were selected as the most reliable. The results of direct current measurements in the entire water column with relatively high horizontal resolution confirm the complicated, multi-path structure and high barotropic component of the West Spitsbergen Current. Measurements show high temporal variability of the volume transport and strong current dependence on wind conditions. The quasi-synoptic northward volume transport across section 78150 0 N from 0021E to the Spitsbergen shelf is estimated at 11.6 Sv, and total heat transport at 70.6 TW.

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Section: Ladcp Resultssupporting

confidence: 83%

The West Spitsbergen Current volume and heat transport from synoptic observations in summer

Walczowski

Piechura

Osiński

et al. 2005

Deep Sea Research Part I: Oceanographic Research Papers

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“…During post processing, misalignment angles and amplitude factors were obtained from water track calibration. Uncertainties of 1h averages were 1–3 cm s −1 , similar to what has been achieved during previous cruises with the same instrumentation [ Fischer et al , 2003].…”

Section: Observationssupporting

confidence: 80%

Oxygen tongues and zonal currents in the equatorial Atlantic

Brandt

Hormann

Bourlès³

et al. 2008

J. Geophys. Res.

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[1] Equatorial zonal currents and associated oxygen distributions are studied using shipboard hydrographic data, trajectories from isopycnic floats drifting at about 300 m depth, and velocity time series from the upper 1100 m obtained at two equatorial moorings located at 35°W and 23°W. Mean profiles of zonal velocity measured by moored acoustic Doppler current profilers yielded a westward flowing Equatorial Intermediate Current (EIC) below the Equatorial Undercurrent (EUC) at both locations. The EIC consists of two westward current cores at about 250 and 450 m. The upper core of the EIC deepens by about 30 m from 23°W, where it has a mean velocity of 6 ± 2 cm s À1 , to 35°W, where the mean is 5 ± 3 cm s À1. The lower core of the EIC is about twice as strong with 12 ± 1 cm s À1 at 23°W and 9 ± 2 cm s À1 at 35°W. The flow below the EUC is characterized by substantial interannual variability. From May to December 2005 a strong, zonally coherent eastward jet occurred at 300 to 350 m depth, found to be an expression of shallow stacked jets superimposed on the mean EIC. Shipboard hydrographic observations in June-July 2006 revealed the existence of a high-oxygen tongue that can be traced from 35°W to 10°W in the depth range of the eastward jet prevailing during the preceding year. On the basis of an advection-diffusion balance, it is suggested that the oxygen decrease from 35°W to 10°W within the oxygen tongue is mainly balanced by lateral eddy diffusivity and oxygen consumption, with diapycnal turbulent diffusivity playing only a minor role.

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“…Vessel‐mounted ADCPs (vm‐ADCPs) are continuously recording velocities throughout the section. The accuracy of 1‐hr averaged vm‐ADCP data is better than 2–4 cm/s (Fischer et al, ). Lowered ADCPs (l‐ADCPs) are attached in pairs of upward and downward looking instruments to a CTD (conductivity‐temperature‐depth) rosette and record velocities during CTD casts typically performed on a uniform latitude grid with half‐degree resolution.…”

Section: Methodsmentioning

confidence: 99%

Interannual Variability of the Atlantic North Equatorial Undercurrent and Its Impact on Oxygen

et al. 2019

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The North Equatorial Undercurrent (NEUC) has been suggested to act as an important oxygen supply route toward the oxygen minimum zone in the eastern tropical North Atlantic. Observational estimates of the mean NEUC strength are uncertain due to the presence of elevated mesoscale activities, and models have difficulties in simulating a realistic NEUC. Here we investigate the interannual variability of the NEUC and its impact onto oxygen based on the output of a high‐resolution Ocean General Circulation Model (OGCM) and contrast the results with an unique data set of 21 ship sections along 23° W and a conceptual model. We find that the interannual variability of the NEUC in the OGCM is related to the Atlantic meridional mode with a stronger and more northward NEUC during negative Atlantic meridional mode phases. Discrepancies between the OGCM and observations suggest a different role of the NEUC in setting the regional oxygen distribution. In the model a stronger NEUC is associated with a weaker oxygen supply toward the east. We attribute this to a too strong recirculation between the NEUC and the northern branch of the South Equatorial Current in the OGCM. Idealized experiments with the conceptual model support the idea that the impact of NEUC variability on oxygen depends on the source water pathway. A strengthening of the NEUC supplied out of the western boundary acts to increase oxygen levels within the NEUC. A strengthening of the recirculations between NEUC and the northern branch of the South Equatorial Current results in a reduction of oxygen levels within the NEUC.

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Surveying the Upper Ocean with the Ocean Surveyor: A New Phased Array Doppler Current Profiler

Cited by 34 publications

References 11 publications

The West Spitsbergen Current volume and heat transport from synoptic observations in summer

The West Spitsbergen Current volume and heat transport from synoptic observations in summer

Oxygen tongues and zonal currents in the equatorial Atlantic

Interannual Variability of the Atlantic North Equatorial Undercurrent and Its Impact on Oxygen

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