Lateral diffusivity from tracer release experiments in the tropical North Atlantic thermocline.

Banyte, Donata, Visbeck, Martin , Tanhua, Toste , Fischer, Tim , Krahmann, Gerd and Karstensen, Johannes (2013) Lateral diffusivity from tracer release experiments in the tropical North Atlantic thermocline. Open Access Journal of Geophysical Research: Oceans, 118 (4). pp. 1-15. DOI 10.1002/jgrc.20211.

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Lateral diffusivity is computed from a tracer release experiment in the northeastern tropical Atlantic thermocline. The uncertainties of the estimates are inferred from a synthetic particle release using a high-resolution ocean circulation model. The main method employed to compute zonal and meridional components of lateral diffusivity is the growth of the second moment of a cloud of tracer. The application of an areal comparison method for estimating tracer-based diffusivity in the field experiments is also discussed. The best estimate of meridional eddy diffusivity in the Guinea Upwelling region at about 300 m depth is estimated to be inline image m2 s−1. The zonal component of lateral diffusivity is estimated to be inline image m2 s−1, while areal comparison method yields areal equivalent zonal diffusivity component of inline image m2 s−1. In comparison to Ky, Kx is about twice larger, resulting from the tracer patch stretching by zonal jets. Employed conceptual jet model indicates that zonal jet velocities of about inline image m s−1 are required to explain the enhancement of the zonal eddy diffusivity component. Finally, different sampling strategies are tested on synthetic tracer release experiments. They indicate that the best sampling strategy is a sparse regular sampling grid covering most of the tracer patch.

Document Type: Article
Additional Information: WOS:000324913700032
Keywords: tracer release experiment; isopycnal mixing; North Atlantic OMZ
Research affiliation: OceanRep > SFB 754 > A3
OceanRep > SFB 754
OceanRep > The Future Ocean - Cluster of Excellence
OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-CH Chemical Oceanography
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-PO Physical Oceanography
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/jgrc.20211
ISSN: 2169-9275
Projects: SFB754, Future Ocean
Date Deposited: 06 Jun 2013 11:07
Last Modified: 24 Sep 2019 00:02

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