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Burmeister, Kristin; Lübbecke, Joke; Brandt, Peter; Duteil, Olaf (2019): Interannual variability of the Atlantic North Equatorial Undercurrent and its impact on oxygen. PANGAEA, https://doi.org/10.1594/PANGAEA.899052

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Abstract:
The North Equatorial Undercurrent (NEUC) has been suggested to act as an important oxygen supply route towards 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 (AMM) with a stronger and more northward NEUC during negative AMM phases. Discrepancies between 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 towards the east. We attribute this to a too strong recirculation between the NEUC and the northern branch of the South Equatorial Current (nSEC) 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 nSEC results in a reduction of oxygen levels within the NEUC.
Related to:
Burmeister, Kristin; Lübbecke, Joke; Brandt, Peter; Duteil, Olaf (2019): Interannual Variability of the Atlantic North Equatorial Undercurrent and Its Impact on Oxygen. Journal of Geophysical Research: Oceans, 124(4), 2348-2373, https://doi.org/10.1029/2018JC014760
Funding:
German Research Foundation (DFG), grant/award no. 27542298: Climate - Biogeochemistry Interactions in the Tropical Ocean
Coverage:
Median Latitude: 7.633024 * Median Longitude: -25.365472 * South-bound Latitude: -33.911860 * West-bound Longitude: -68.937900 * North-bound Latitude: 28.144100 * East-bound Longitude: 18.434600
Date/Time Start: 2002-10-13T00:00:00 * Date/Time End: 2018-03-14T00:00:00
Size:
24 datasets

Datasets listed in this bibliography

  1. Brandt, P; Czeschel, R (2019): ADCP current measurements during METEOR cruise M145. https://doi.org/10.1594/PANGAEA.899170
  2. Brandt, P; Czeschel, R; Schütte, F et al. (2017): ADCP current measurements (38 and 75 kHz) during METEOR cruise M119. https://doi.org/10.1594/PANGAEA.877375
  3. Brandt, P; Funk, A; Krahmann, G (2017): ADCP current measurements (38 and 75 kHz) during Maria S. Merian cruise MSM18/2. https://doi.org/10.1594/PANGAEA.877352
  4. Brandt, P; Funk, A; Krahmann, G (2017): ADCP current measurements (300 and 75 kHz) during L'Atalante cruise AT08_4 (IFM_GEOMAR/4). https://doi.org/10.1594/PANGAEA.877362
  5. Brandt, P; Hahn, J; Czeschel, R et al. (2017): ADCP current measurements during POLARSTERN cruise PS88.2 (ANT-XXX/1.2). https://doi.org/10.1594/PANGAEA.877353
  6. Brandt, P; Krahmann, G (2017): Lowered ADCP data during METEOR cruise M119. https://doi.org/10.1594/PANGAEA.877351
  7. Brandt, P; Krahmann, G (2019): Physical oceanography (CTD) during METEOR cruise M145. https://doi.org/10.1594/PANGAEA.904382
  8. Brandt, P; Vogt, M; Krahmann, G (2017): ADCP current measurements (38 kHz) during METEOR cruise M81/1. https://doi.org/10.1594/PANGAEA.877359
  9. Dengler, M; Krahmann, G (2019): Physical oceanography (CTD) during METEOR cruise M130. https://doi.org/10.1594/PANGAEA.904367
  10. Krahmann, G (2013): Lowered ADCP data during L'ATALANTE cruise ATA_IFMGEOMAR/4. https://doi.org/10.1594/PANGAEA.811565
  11. Krahmann, G (2013): Lowered ADCP data during METEOR cruise M80/1. https://doi.org/10.1594/PANGAEA.811718
  12. Krahmann, G (2014): Physical oceanography during L'Atalante cruise ATA_IFMGEOMAR-4. https://doi.org/10.1594/PANGAEA.834325
  13. Krahmann, G (2014): Physical oceanography during Maria S. Merian cruise MSM22. https://doi.org/10.1594/PANGAEA.834588
  14. Krahmann, G (2014): Physical oceanography during METEOR cruise M80/1. https://doi.org/10.1594/PANGAEA.834424
  15. Krahmann, G (2015): Lowered ADCP data during Maria S. Merian cruise MSM22. https://doi.org/10.1594/PANGAEA.846763
  16. Krahmann, G (2016): Lowered ADCP data during METEOR cruise M106. https://doi.org/10.1594/PANGAEA.869634
  17. Krahmann, G (2016): Physical oceanography during METEOR cruise M106. https://doi.org/10.1594/PANGAEA.869361
  18. Krahmann, G (2016): Physical oceanography during METEOR cruise M119. https://doi.org/10.1594/PANGAEA.860484
  19. Krahmann, G; Hahn, J (2018): Current velocities (LADCP) during POLARSTERN cruise PS88.2 (ANT-XXX/1.2). https://doi.org/10.1594/PANGAEA.887769
  20. Krahmann, G; Hahn, J (2018): Physical oceanography (CTD) during POLARSTERN cruise PS88.2 (ANT-XXX/1.2). https://doi.org/10.1594/PANGAEA.887770
  21. Krahmann, G; Hummels, R (2017): ADCP current measurements during METEOR cruise M68/2. https://doi.org/10.1594/PANGAEA.874876
  22. Krahmann, G; Kopte, R (2015): ADCP current measurements during Maria S. Merian cruise MSM22. https://doi.org/10.1594/PANGAEA.841476
  23. Stramma, L (2012): Physical oceanography during METEOR cruise M68/2. https://doi.org/10.1594/PANGAEA.787643
  24. Wallace, DWR; Schafstall, J; Krahmann, G (2017): ADCP current measurements (75 kHz) during METEOR cruise M55/1. https://doi.org/10.1594/PANGAEA.877591