Publication Date:
2022-11-04
Description:
© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Tuchen, F., Brandt, P., Hahn, J., Hummels, R., Krahmann, G., Bourlès, B., Provost, C., McPhaden, M., & Toole, J. Two decades of full-depth current velocity observations from a moored observatory in the central equatorial Atlantic at 0°N, 23°W. Frontiers in Marine Science, 9, (2022): 910979, https://doi.org/10.3389/fmars.2022.910979.
Description:
Regional climate variability in the tropical Atlantic, from interannual to decadal time scales, is inevitably connected to changes in the strength and position of the individual components of the tropical current system with impacts on societally relevant climate hazards such as anomalous rainfall or droughts over the surrounding continents (Bourlès et al., 2019; Foltz et al., 2019). Furthermore, the lateral supply of dissolved oxygen in the tropical Atlantic upper-ocean is closely linked to the zonal current bands (Brandt et al., 2008; Brandt et al., 2012; Burmeister et al., 2020) and especially to the Equatorial Undercurrent (EUC) and its long-term variations with potential implications for regional marine ecosystems (Brandt et al., 2021). The eastward flowing EUC is located between 70 to 200 m depth and forms one of the strongest tropical currents with maximum velocities of up to 1 m s-1 and maximum variability on seasonal time scales (Brandt et al., 2014; Johns et al., 2014). In the intermediate to deep equatorial Atlantic, variability on longer time scales is mainly governed by alternating, vertically-stacked, zonal currents (equatorial deep jets (EDJs); Johnson and Zhang, 2003). At a fixed location, the phases of these jets are propagating downward with time, implying that parts of their energy must propagate upward towards the surface (Brandt et al., 2011). In fact, a pronounced interannual cycle of about 4.5 years, that is associated with EDJs, is projected onto surface parameters such as sea surface temperature or precipitation (Brandt et al., 2011) further demonstrating the importance of understanding equatorial circulation variability and its role in tropical climate variability.
Description:
This study was funded by EU H2020 under grant agreement 817578 TRIATLAS project, by the Deutsche Forschungsgemeinschaft as part of the Sonderforschungsbereich754 “Climate–Biogeochemistry Interactions in the Tropical Ocean” and through several research cruises with RV Meteor, RV Maria S. Merian, RV L'Atalante, and RV Sonne and by the Deutsche Bundesministerium für Bildung und Forschung (BMBF) as part of the projects RACE (03F06518) and by the European Union 7th Framework Programme (FP7) under Grant Agreement 603521. Moored velocity observations were acquired in cooperation with the PIRATA project supported by NOAA (USA), IRD and Meteo-France (France), INPE (Brazil) and the Brazil Navy. This research was performed while FPT held an NRC Research Associateship Award at NOAA’s Atlantic Oceanographic and Meteorological Laboratory. FPT, PB, JH, RH, and GK are grateful for continuing support from GEOMAR Helmholtz Centre for Ocean Research Kiel. MM acknowledges the support of NOAA; PMEL contribution no. 5359. JT's contributions to this study were supported by the U.S. National Science Foundation.
Keywords:
Ocean observations
;
Physical oceanography
;
Equatorial Atlantic circulation
;
Ocean currents
;
Moored observations
;
Climate variability
Repository Name:
Woods Hole Open Access Server
Type:
Article
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