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Quantifying He fluxes from the mantle using multi-tracer data assimilation

A global, coarse-resolution ocean model previously fitted to geostrophic shear estimates and to data of 10 hydrographic parameters and tracers has been used to simulate the (3)He and (4)He distributions resulting from the release of mantle helium from mid-ocean ridges. The model is in very good agre...

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Detalles Bibliográficos
Autor principal: Schlitzer, Reiner
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5069525/
https://www.ncbi.nlm.nih.gov/pubmed/29035254
http://dx.doi.org/10.1098/rsta.2015.0288
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author Schlitzer, Reiner
author_facet Schlitzer, Reiner
author_sort Schlitzer, Reiner
collection PubMed
description A global, coarse-resolution ocean model previously fitted to geostrophic shear estimates and to data of 10 hydrographic parameters and tracers has been used to simulate the (3)He and (4)He distributions resulting from the release of mantle helium from mid-ocean ridges. The model is in very good agreement with (14)C and chlorofluorocarbon data and has realistic global ocean overturning strength as well as water mass formation and transport rates. It is found that previously published global mantle (3)He fluxes are too high by a factor of about 2. In the model, optimal agreement of modelled δ(3)He with data is achieved for a global flux of 450 ± 50 mol (3)He yr(−1). The formulation of He source strengths proportional to ridge spreading rates appears compatible with data. A model/data misfit analysis shows significant and large-scale δ(3)He underestimation in the southwestern Pacific centred over the Lau Backarc Basin (approx. 179° W/20° S). These misfits disappear in a set-up with 30 of the 450 mol yr(−1) global total (3)He flux released in the Lau Basin over a depth range between 1250 and 2500 m. Such He flux contributions are missing in present mantle He source compilations. Hydrothermal fluxes of other trace elements and isotopes (TEI) can be calculated from He fluxes on the basis of TEI : He ratios measured close to the sources. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’.
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spelling pubmed-50695252016-11-28 Quantifying He fluxes from the mantle using multi-tracer data assimilation Schlitzer, Reiner Philos Trans A Math Phys Eng Sci Articles A global, coarse-resolution ocean model previously fitted to geostrophic shear estimates and to data of 10 hydrographic parameters and tracers has been used to simulate the (3)He and (4)He distributions resulting from the release of mantle helium from mid-ocean ridges. The model is in very good agreement with (14)C and chlorofluorocarbon data and has realistic global ocean overturning strength as well as water mass formation and transport rates. It is found that previously published global mantle (3)He fluxes are too high by a factor of about 2. In the model, optimal agreement of modelled δ(3)He with data is achieved for a global flux of 450 ± 50 mol (3)He yr(−1). The formulation of He source strengths proportional to ridge spreading rates appears compatible with data. A model/data misfit analysis shows significant and large-scale δ(3)He underestimation in the southwestern Pacific centred over the Lau Backarc Basin (approx. 179° W/20° S). These misfits disappear in a set-up with 30 of the 450 mol yr(−1) global total (3)He flux released in the Lau Basin over a depth range between 1250 and 2500 m. Such He flux contributions are missing in present mantle He source compilations. Hydrothermal fluxes of other trace elements and isotopes (TEI) can be calculated from He fluxes on the basis of TEI : He ratios measured close to the sources. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’. The Royal Society 2016-11-28 /pmc/articles/PMC5069525/ /pubmed/29035254 http://dx.doi.org/10.1098/rsta.2015.0288 Text en © 2015 The Authors. http://creativecommons.org/licenses/by/4.0/ Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
spellingShingle Articles
Schlitzer, Reiner
Quantifying He fluxes from the mantle using multi-tracer data assimilation
title Quantifying He fluxes from the mantle using multi-tracer data assimilation
title_full Quantifying He fluxes from the mantle using multi-tracer data assimilation
title_fullStr Quantifying He fluxes from the mantle using multi-tracer data assimilation
title_full_unstemmed Quantifying He fluxes from the mantle using multi-tracer data assimilation
title_short Quantifying He fluxes from the mantle using multi-tracer data assimilation
title_sort quantifying he fluxes from the mantle using multi-tracer data assimilation
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5069525/
https://www.ncbi.nlm.nih.gov/pubmed/29035254
http://dx.doi.org/10.1098/rsta.2015.0288
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