Salinity changes in the World Ocean since 1950 in relation to changing surface freshwater fluxes
Salinity changes in the World Ocean since 1950 in relation to changing surface freshwater fluxes
Global hydrographic and air–sea freshwater flux datasets are used to investigate ocean salinity changes over 1950–2010 in relation to surface freshwater flux. On multi-decadal timescales, surface salinity increases (decreases) in evaporation (precipitation) dominated regions, the Atlantic–Pacific salinity contrast increases, and the upper thermocline salinity maximum increases while the salinity minimum of intermediate waters decreases. Potential trends in E–P are examined for 1950–2010 (using two reanalyses) and 1979–2010 (using four reanalyses and two blended products). Large differences in the 1950–2010 E–P trend patterns are evident in several regions, particularly the North Atlantic. For 1979–2010 some coherency in the spatial change patterns is evident but there is still a large spread in trend magnitude and sign between the six E–P products. However, a robust pattern of increased E–P in the southern hemisphere subtropical gyres is seen in all products. There is also some evidence in the tropical Pacific for a link between the spatial change patterns of salinity and E–P associated with ENSO. The water cycle amplification rate over specific regions is subsequently inferred from the observed 3-D salinity change field using a salt conservation equation in variable isopycnal volumes, implicitly accounting for the migration of isopycnal surfaces. Inferred global changes of E–P over 1950–2010 amount to an increase of 1 ± 0.6 % in net evaporation across the subtropics and an increase of 4.2 ± 2 % in net precipitation across subpolar latitudes. Amplification rates are approximately doubled over 1979–2010, consistent with accelerated broad-scale warming but also coincident with much improved salinity sampling over the latter period.
Salinity, Freshwater flux, Evaporation, Precipitation, Hydrological cycle
709-736
Skliris, Nikolaos
07af7484-2e14-49aa-9cd3-1979ea9b064e
Marsh, Robert
702c2e7e-ac19-4019-abd9-a8614ab27717
Josey, Simon A.
2252ab7f-5cd2-49fd-a951-aece44553d93
Good, Simon A.
6bf72f0c-2772-4537-a6f8-c7f9e961513c
Liu, Chunlei
44c69554-00c4-465c-a6f5-085662f547e6
Allan, Richard P.
0ebcf6b4-ba53-43f2-8931-319280d6650c
August 2014
Skliris, Nikolaos
07af7484-2e14-49aa-9cd3-1979ea9b064e
Marsh, Robert
702c2e7e-ac19-4019-abd9-a8614ab27717
Josey, Simon A.
2252ab7f-5cd2-49fd-a951-aece44553d93
Good, Simon A.
6bf72f0c-2772-4537-a6f8-c7f9e961513c
Liu, Chunlei
44c69554-00c4-465c-a6f5-085662f547e6
Allan, Richard P.
0ebcf6b4-ba53-43f2-8931-319280d6650c
Skliris, Nikolaos, Marsh, Robert, Josey, Simon A., Good, Simon A., Liu, Chunlei and Allan, Richard P.
(2014)
Salinity changes in the World Ocean since 1950 in relation to changing surface freshwater fluxes.
Climate Dynamics, 43 (3-4), .
(doi:10.1007/s00382-014-2131-7).
Abstract
Global hydrographic and air–sea freshwater flux datasets are used to investigate ocean salinity changes over 1950–2010 in relation to surface freshwater flux. On multi-decadal timescales, surface salinity increases (decreases) in evaporation (precipitation) dominated regions, the Atlantic–Pacific salinity contrast increases, and the upper thermocline salinity maximum increases while the salinity minimum of intermediate waters decreases. Potential trends in E–P are examined for 1950–2010 (using two reanalyses) and 1979–2010 (using four reanalyses and two blended products). Large differences in the 1950–2010 E–P trend patterns are evident in several regions, particularly the North Atlantic. For 1979–2010 some coherency in the spatial change patterns is evident but there is still a large spread in trend magnitude and sign between the six E–P products. However, a robust pattern of increased E–P in the southern hemisphere subtropical gyres is seen in all products. There is also some evidence in the tropical Pacific for a link between the spatial change patterns of salinity and E–P associated with ENSO. The water cycle amplification rate over specific regions is subsequently inferred from the observed 3-D salinity change field using a salt conservation equation in variable isopycnal volumes, implicitly accounting for the migration of isopycnal surfaces. Inferred global changes of E–P over 1950–2010 amount to an increase of 1 ± 0.6 % in net evaporation across the subtropics and an increase of 4.2 ± 2 % in net precipitation across subpolar latitudes. Amplification rates are approximately doubled over 1979–2010, consistent with accelerated broad-scale warming but also coincident with much improved salinity sampling over the latter period.
This record has no associated files available for download.
More information
e-pub ahead of print date: May 2014
Published date: August 2014
Keywords:
Salinity, Freshwater flux, Evaporation, Precipitation, Hydrological cycle
Organisations:
Physical Oceanography, Marine Physics and Ocean Climate
Identifiers
Local EPrints ID: 365182
URI: http://eprints.soton.ac.uk/id/eprint/365182
ISSN: 0930-7575
PURE UUID: b8e9e9f3-bdf2-45e5-9dd6-6c4609bb6932
Catalogue record
Date deposited: 23 May 2014 13:18
Last modified: 15 Mar 2024 03:39
Export record
Altmetrics
Contributors
Author:
Simon A. Josey
Author:
Simon A. Good
Author:
Chunlei Liu
Author:
Richard P. Allan
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.
Loading...
View more statistics