Articles | Volume 19, issue 3
https://doi.org/10.5194/os-19-923-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-19-923-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
28 Jun 2023
Research article |
| 28 Jun 2023
| 28 Jun 2023
Factors influencing the meridional width of the equatorial deep jets
Swantje Bastin
CORRESPONDING AUTHOR
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
now at: Climate Variability Department, Max Planck Institute for Meteorology, Hamburg, Germany
Martin Claus
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Faculty of Mathematics and Natural Sciences, Kiel University, Kiel, Germany
Richard J. Greatbatch
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Faculty of Mathematics and Natural Sciences, Kiel University, Kiel, Germany
Peter Brandt
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Faculty of Mathematics and Natural Sciences, Kiel University, Kiel, Germany
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Ocean Sci., 13, 531–549, https://doi.org/10.5194/os-13-531-2017, https://doi.org/10.5194/os-13-531-2017, 2017
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Ocean Sci. Discuss., https://doi.org/10.5194/os-2017-24, https://doi.org/10.5194/os-2017-24, 2017
Revised manuscript not accepted
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In coupled global atmosphere ocean models a feedback from ocean surface currents to atmospheric winds was found. Surface winds are energized by about 30 % of the ocean currents. We were able to implement this feedback in uncoupled ocean models which results in a realistic surface flux coupling. Due to changes in the dissipation the kinetic energy of the time-variable flow is increased up to 10 % when this feedback is implemented. Implementation in other models should be straightforward.
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Biogeosciences, 13, 5865–5881, https://doi.org/10.5194/bg-13-5865-2016, https://doi.org/10.5194/bg-13-5865-2016, 2016
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Mesoscale eddies with very low–oxygen concentrations at shallow depth have been recently discovered in the eastern tropical North Atlantic. Our analysis shows that low oxygen eddies occur more frequent than expected and are found even close to the equator (8° N). From budget calculations we show that an oxygen reduction of 7 µmol/kg in the depth range of 50–150 m in the eastern tropical North Atlantic (peak reduction is 16 µmol/kg at 100 m depth) can be associated with the dispersion of these eddies.
Florian Schütte, Peter Brandt, and Johannes Karstensen
Ocean Sci., 12, 663–685, https://doi.org/10.5194/os-12-663-2016, https://doi.org/10.5194/os-12-663-2016, 2016
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We want to examine the characteristics of mesoscale eddies in the tropical northeastern Atlantic. They serve as transport agents, exporting water from the coast into the open ocean. Traditionally eddies are categorized with respect to their rotation: cyclonic and anticyclonic. But we could identify, with a combination of different satellite products, a third type called "anticyclonic mode-water eddy" transporting much larger anomalies. We propose a distinction into three classes for further studies.
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This study is the first report of the formation of dead zones in the open ocean. A combination of multiple ocean observing system elements (mooring, floats, satellites, ships) allowed us to reconstruct the generation of the dead zones and to connect the formation to enhanced respiration within mesoscale ocean eddies. The dead zones present specific threats to the ecosystem, such as the interruption of the diurnal migration of zooplankters.
P. Brandt, H. W. Bange, D. Banyte, M. Dengler, S.-H. Didwischus, T. Fischer, R. J. Greatbatch, J. Hahn, T. Kanzow, J. Karstensen, A. Körtzinger, G. Krahmann, S. Schmidtko, L. Stramma, T. Tanhua, and M. Visbeck
Biogeosciences, 12, 489–512, https://doi.org/10.5194/bg-12-489-2015, https://doi.org/10.5194/bg-12-489-2015, 2015
Short summary
Short summary
Our observational study looks at the structure of the eastern tropical North Atlantic (ETNA) oxygen minimum zone (OMZ) in comparison with the less-ventilated, eastern tropical South Pacific OMZ. We quantify the OMZ’s oxygen budget composed of consumption, advection, lateral and vertical mixing. Substantial oxygen variability is observed on interannual to multidecadal timescales. The deoxygenation of the ETNA OMZ during the last decades represents a substantial imbalance of the oxygen budget.
M. Thoma, R. Gerdes, R. J. Greatbatch, and H. Ding
Geosci. Model Dev., 8, 51–68, https://doi.org/10.5194/gmd-8-51-2015, https://doi.org/10.5194/gmd-8-51-2015, 2015
T. Fischer, D. Banyte, P. Brandt, M. Dengler, G. Krahmann, T. Tanhua, and M. Visbeck
Biogeosciences, 10, 5079–5093, https://doi.org/10.5194/bg-10-5079-2013, https://doi.org/10.5194/bg-10-5079-2013, 2013
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Short summary
Equatorial deep jets are ocean currents that flow along the Equator in the deep oceans. They are relevant for oxygen transport and tropical surface climate, but their dynamics are not yet entirely understood. We investigate different factors leading to the jets being broader than theory predicts. Mainly using an ocean model, but corroborating the results with shipboard observations, we show that loss of momentum is the main factor for the broadening but that meandering also contributes.
Equatorial deep jets are ocean currents that flow along the Equator in the deep oceans. They are...
