The University of Southampton
University of Southampton Institutional Repository

Estimating the recharge properties of the deep ocean using noble gases and helium isotopes

Estimating the recharge properties of the deep ocean using noble gases and helium isotopes
Estimating the recharge properties of the deep ocean using noble gases and helium isotopes
The distribution of noble gases and helium isotopes in the dense shelf waters of Antarctica reflect the boundary conditions near the ocean surface: air-sea exchange, sea ice formation and subsurface ice melt. We use a non-linear least-squares solution to determine the value of the recharge temperature and salinity, as well as the excess air injection and glacial meltwater content throughout the water column and in the precursor to Antarctic Bottom Water. The noble gas-derived recharge temperature and salinity in the Weddell Gyre are -1.95 °C and 34.95 psu near 5500 m; these cold, salty recharge values are a result of surface cooling as well as brine rejection during sea ice formation in Antarctic polynyas. In comparison, the global value for deep water recharge temperature is -0.44 °C at 5500 m, which is 1.5 °C warmer than the southern hemisphere deep water recharge temperature, reflecting the contribution from the north Atlantic. The contrast between northern and southern hemisphere recharge properties highlight the impact of sea ice formation on setting the gas properties in southern sourced deep water. Below 1000 m, glacial meltwater averages 3.5 ‰ by volume and represents greater than 50% of the excess neon and argon found in the water column. These results indicate glacial melt has a non-negligible impact on the atmospheric gas content of Antarctic Bottom Water.
meridional overturning circulation, glacial meltwater, ocean carbon cycle, Southern Ocean upwelling, sea ice processes
5959-5979
Loose, Brice
64fb1ea7-f908-4fe2-a0c1-156c9c2c18e7
Jenkins, William J.
c1e43414-a6ab-4ca1-92d5-24e1c09ad6d5
Moriarty, Roisin
0a169ba6-d3cd-42c1-8561-5706e072b338
Brown, Peter
e21132aa-29de-4c0e-846a-f090ddda0dbc
Jullion, Loic
bc5dea82-19db-4e37-bc12-e5bb2c257a99
Naviera Garabato, Alberto C.
97c0e923-f076-4b38-b89b-938e11cea7a6
Torres-Valdes, Sinhue
50398d55-4df9-4b9e-a431-16936300650c
Hoppema, Mario
6f021392-ab2f-4167-8cb0-016b601d392e
Ballentine, Chris
2453fa25-fe95-4bf1-92f3-7931431326a5
Meredith, Michael P.
25fd5f1c-f3ed-40a2-af59-5a7074a25fcd
Loose, Brice
64fb1ea7-f908-4fe2-a0c1-156c9c2c18e7
Jenkins, William J.
c1e43414-a6ab-4ca1-92d5-24e1c09ad6d5
Moriarty, Roisin
0a169ba6-d3cd-42c1-8561-5706e072b338
Brown, Peter
e21132aa-29de-4c0e-846a-f090ddda0dbc
Jullion, Loic
bc5dea82-19db-4e37-bc12-e5bb2c257a99
Naviera Garabato, Alberto C.
97c0e923-f076-4b38-b89b-938e11cea7a6
Torres-Valdes, Sinhue
50398d55-4df9-4b9e-a431-16936300650c
Hoppema, Mario
6f021392-ab2f-4167-8cb0-016b601d392e
Ballentine, Chris
2453fa25-fe95-4bf1-92f3-7931431326a5
Meredith, Michael P.
25fd5f1c-f3ed-40a2-af59-5a7074a25fcd

Loose, Brice, Jenkins, William J., Moriarty, Roisin, Brown, Peter, Jullion, Loic, Naviera Garabato, Alberto C., Torres-Valdes, Sinhue, Hoppema, Mario, Ballentine, Chris and Meredith, Michael P. (2016) Estimating the recharge properties of the deep ocean using noble gases and helium isotopes. Journal of Geophysical Research: Oceans, 121 (8), 5959-5979. (doi:10.1002/2016JC011809).

Record type: Article

Abstract

The distribution of noble gases and helium isotopes in the dense shelf waters of Antarctica reflect the boundary conditions near the ocean surface: air-sea exchange, sea ice formation and subsurface ice melt. We use a non-linear least-squares solution to determine the value of the recharge temperature and salinity, as well as the excess air injection and glacial meltwater content throughout the water column and in the precursor to Antarctic Bottom Water. The noble gas-derived recharge temperature and salinity in the Weddell Gyre are -1.95 °C and 34.95 psu near 5500 m; these cold, salty recharge values are a result of surface cooling as well as brine rejection during sea ice formation in Antarctic polynyas. In comparison, the global value for deep water recharge temperature is -0.44 °C at 5500 m, which is 1.5 °C warmer than the southern hemisphere deep water recharge temperature, reflecting the contribution from the north Atlantic. The contrast between northern and southern hemisphere recharge properties highlight the impact of sea ice formation on setting the gas properties in southern sourced deep water. Below 1000 m, glacial meltwater averages 3.5 ‰ by volume and represents greater than 50% of the excess neon and argon found in the water column. These results indicate glacial melt has a non-negligible impact on the atmospheric gas content of Antarctic Bottom Water.

Text
jgrc21807.pdf - Accepted Manuscript
Download (2MB)
Text
jgrc21807.pdf - Version of Record
Download (4MB)

More information

Submitted date: 19 March 2016
Accepted/In Press date: 16 June 2016
e-pub ahead of print date: 18 August 2016
Published date: 18 August 2016
Keywords: meridional overturning circulation, glacial meltwater, ocean carbon cycle, Southern Ocean upwelling, sea ice processes
Organisations: Marine Biogeochemistry, Physical Oceanography

Identifiers

Local EPrints ID: 390013
URI: http://eprints.soton.ac.uk/id/eprint/390013
PURE UUID: 65133474-80bd-47c4-9d20-af33b8a706ea
ORCID for Alberto C. Naviera Garabato: ORCID iD orcid.org/0000-0001-6071-605X

Catalogue record

Date deposited: 13 Jul 2016 13:03
Last modified: 15 Mar 2024 03:24

Export record

Altmetrics

Contributors

Author: Brice Loose
Author: William J. Jenkins
Author: Roisin Moriarty
Author: Peter Brown
Author: Loic Jullion
Author: Sinhue Torres-Valdes
Author: Mario Hoppema
Author: Chris Ballentine
Author: Michael P. Meredith

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×