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From the subtropics to the equator in the Southwest Pacific: Continental material fluxes quantified using neodymium data along modeled thermocline water pathways

Citation

Grenier, M and Jeandel, C and Cravatte, S, From the subtropics to the equator in the Southwest Pacific: Continental material fluxes quantified using neodymium data along modeled thermocline water pathways, Journal of Geophysical Research: Oceans, 119, (6) pp. 3948-3966. ISSN 2169-9275 (2014) [Refereed Article]


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Copyright Statement

Copyright 2014 American Geophysical Union

DOI: doi:10.1002/2013JC009670

Abstract

The southwestern tropical Pacific, part of a major pathway for waters feeding the Equatorial Undercurrent, is a region of important geochemical enrichment through land-ocean boundary exchange. Here we develop an original method based on the coupling between dynamical modeling and geochemical tracer data to identify regions of enrichment along the water pathways from the subtropics to the equator, and to allow a refined quantification of continental material fluxes. Neodymium data are interpreted with the help of modeled Lagrangian trajectories of an Ocean General Circulation Model. We reveal that upper and lower thermocline waters have different pathways together with different geochemical evolutions. The upper thermocline waters entering the Solomon Sea mainly originate from the central subtropical gyre, enter the Coral Sea in the North Vanuatu Jet and likely receive radiogenic neodymium from the basaltic island margins encountered along their route. The lower thermocline waters entering the Solomon Sea mainly originate from northeast of New Zealand and enter the Coral Sea in the North Caledonian Jet. Depletion of their neodymium content likely occurs when flowing along the Australian and Papua coasts. Downstream from the Solomon Sea, waters flowing along the Papua New Guinea margins near the Sepik river mouth become surprisingly depleted in their neodymium content in the upper thermocline while enriched in the lower thermocline. This coupled approach is proposed as strong support to interpret the origin of the equatorial Pacific natural fertilization through a better understanding of the circulation, important objectives of the international GEOTRACES and SPICE programs, respectively.

Item Details

Item Type:Refereed Article
Keywords:continental material flux, neodumium data, thermocline water pathways, equatorial undercurrent, tropical Pacific
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical Oceanography
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
UTAS Author:Grenier, M (Dr Melanie Grenier)
ID Code:118231
Year Published:2014
Web of Science® Times Cited:17
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2017-07-07
Last Modified:2018-04-17
Downloads:100 View Download Statistics

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