Seasonal Variability of the Mauritania Current and Hydrography at 18°N.

Klenz, Thilo , Dengler, Marcus and Brandt, Peter (2018) Seasonal Variability of the Mauritania Current and Hydrography at 18°N. Open Access Journal of Geophysical Research: Oceans, 123 (11). pp. 8122-8137. DOI 10.1029/2018JC014264.

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Abstract

Extensive field campaigns in the Mauritanian upwelling region between 2005 and 2016 provide the database for analyzing the seasonal variability of the eastern boundary circulation (EBC) and associated water mass distribution at 18°N. The data set includes shipboard upper ocean current, hydrographic, and oxygen measurements from nine research cruises conducted during upwelling (December to April) and relaxation (May to July) seasons. During the upwelling season, the EBC closely resembles a classical eastern boundary current regime, with a poleward undercurrent flowing beneath an equatorward coastal jet. In contrast, elevated poleward flow exceeding 30 cm/s and extending from the surface down to 250-m depth is observed during the relaxation season. The pronounced seasonal variability of the across-shore structure of the EBC can be related to local wind forcing and is in general agreement with Sverdrup balance. The EBC transport is correlated to the wind stress curl leading the transport by 7 days. The short lead time suggests a fast response of locally forced waves adjusting the EBC to wind forcing. The seasonal and vertical water mass distribution is presented based on hydrographic observations. The meridional oxygen distribution and corresponding water mass partitioning into South and North Atlantic Central Water masses reveal a possible northerly ventilation pathway in the deeper layers of the central water stratum. Our results suggest that the poleward surface flow and the poleward undercurrent both are a consequence of the cyclonic wind stress curl forcing and thus propose to name it the Mauritania Current.

Document Type: Article
Funder compliance: info:eu-repo/grantAgreement/EC/FP7/603521
Keywords: central water, Mauritania Current, seasonal variability, Sverdrup, wind stress curl
Research affiliation: OceanRep > SFB 754 > B6
OceanRep > SFB 754 > A4
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-PO Physical Oceanography
OceanRep > SFB 754
Refereed: Yes
Open Access Journal?: No
Publisher: AGU (American Geophysical Union), Wiley
Projects: PREFACE, SFB754
Expeditions/Models/Experiments:
Date Deposited: 27 Nov 2018 11:26
Last Modified: 19 Mar 2021 11:36
URI: https://oceanrep.geomar.de/id/eprint/44753

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