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Improved estimates of water cycle change from ocean salinity: the key role of ocean warming

Improved estimates of water cycle change from ocean salinity: the key role of ocean warming
Improved estimates of water cycle change from ocean salinity: the key role of ocean warming

Changes in the global water cycle critically impact environmental, agricultural, and energy systems relied upon by humanity (Jiménez Cisneros et al 2014 Climate Change 2014: Impacts, Adaptation, and Vulnerability (Cambridge: Cambridge University Press)). Understanding recent water cycle change is essential in constraining future projections. Warming-induced water cycle change is expected to amplify the pattern of sea surface salinity (Durack et al 2012 Science 336 455–8). A puzzle has, however, emerged. The surface salinity pattern has amplified by 5%–8% since the 1950s (Durack et al 2012 Science 336 455–8, Skliris et al 2014 Clim. Dyn. 43 709–36) while the water cycle is thought to have amplified at close to half that rate (Durack et al 2012 Science 336 455–8, Skliris et al 2016 Sci. Rep. 6 752). This discrepancy is also replicated in climate projections of the 21st century (Durack et al 2012 Science 336 455–8). Using targeted numerical ocean model experiments we find that, while surface water fluxes due to water cycle change and ice mass loss amplify the surface salinity pattern, ocean warming exerts a substantial influence. Warming increases near-surface stratification, inhibiting the decay of existing salinity contrasts and further amplifying surface salinity patterns. Observed ocean warming can explain approximately half of observed surface salinity pattern changes from 1957–2016 with ice mass loss playing a minor role. Water cycle change of 3.6% ± 2.1% per degree Celsius of surface air temperature change is sufficient to explain the remaining observed salinity pattern change.

Climate change, Ocean salinity, Ocean warming, Water cycle
1748-9318
Zika, Jan D.
1843cce7-77ce-4ef6-9f79-bcf4f9db30e5
Skliris, Nikolaos
07af7484-2e14-49aa-9cd3-1979ea9b064e
Blaker, Adam T.
94efe8b2-c744-4e90-87d7-db19ffa41200
Marsh, Robert
702c2e7e-ac19-4019-abd9-a8614ab27717
Nurser, A. J.George
2493ef9a-21e9-4d8b-9c32-08677e7e145a
Josey, Simon A.
2252ab7f-5cd2-49fd-a951-aece44553d93
Zika, Jan D.
1843cce7-77ce-4ef6-9f79-bcf4f9db30e5
Skliris, Nikolaos
07af7484-2e14-49aa-9cd3-1979ea9b064e
Blaker, Adam T.
94efe8b2-c744-4e90-87d7-db19ffa41200
Marsh, Robert
702c2e7e-ac19-4019-abd9-a8614ab27717
Nurser, A. J.George
2493ef9a-21e9-4d8b-9c32-08677e7e145a
Josey, Simon A.
2252ab7f-5cd2-49fd-a951-aece44553d93

Zika, Jan D., Skliris, Nikolaos, Blaker, Adam T., Marsh, Robert, Nurser, A. J.George and Josey, Simon A. (2018) Improved estimates of water cycle change from ocean salinity: the key role of ocean warming. Environmental Research Letters, 13 (7), [074036]. (doi:10.1088/1748-9326/aace42).

Record type: Article

Abstract

Changes in the global water cycle critically impact environmental, agricultural, and energy systems relied upon by humanity (Jiménez Cisneros et al 2014 Climate Change 2014: Impacts, Adaptation, and Vulnerability (Cambridge: Cambridge University Press)). Understanding recent water cycle change is essential in constraining future projections. Warming-induced water cycle change is expected to amplify the pattern of sea surface salinity (Durack et al 2012 Science 336 455–8). A puzzle has, however, emerged. The surface salinity pattern has amplified by 5%–8% since the 1950s (Durack et al 2012 Science 336 455–8, Skliris et al 2014 Clim. Dyn. 43 709–36) while the water cycle is thought to have amplified at close to half that rate (Durack et al 2012 Science 336 455–8, Skliris et al 2016 Sci. Rep. 6 752). This discrepancy is also replicated in climate projections of the 21st century (Durack et al 2012 Science 336 455–8). Using targeted numerical ocean model experiments we find that, while surface water fluxes due to water cycle change and ice mass loss amplify the surface salinity pattern, ocean warming exerts a substantial influence. Warming increases near-surface stratification, inhibiting the decay of existing salinity contrasts and further amplifying surface salinity patterns. Observed ocean warming can explain approximately half of observed surface salinity pattern changes from 1957–2016 with ice mass loss playing a minor role. Water cycle change of 3.6% ± 2.1% per degree Celsius of surface air temperature change is sufficient to explain the remaining observed salinity pattern change.

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Zika 2018 Environ. Res. Lett. 13 074036 - Version of Record
Available under License Creative Commons Attribution.
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More information

Accepted/In Press date: 21 June 2018
e-pub ahead of print date: 19 July 2018
Published date: 19 July 2018
Keywords: Climate change, Ocean salinity, Ocean warming, Water cycle

Identifiers

Local EPrints ID: 426533
URI: http://eprints.soton.ac.uk/id/eprint/426533
ISSN: 1748-9318
PURE UUID: 131932a6-48e8-4524-b5da-b710b5ee7d08

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Date deposited: 30 Nov 2018 17:30
Last modified: 09 Jan 2022 06:52

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Contributors

Author: Jan D. Zika
Author: Adam T. Blaker
Author: Robert Marsh
Author: A. J.George Nurser
Author: Simon A. Josey

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