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The role of mean ocean salinity in climate
Author(s)
Language
English
Obiettivo Specifico
3A. Geofisica marina e osservazioni multiparametriche a fondo mare
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
2-3/49 (2010)
Publisher
elsevier
Pages (printed)
108-123
Issued date
2010
Abstract
We describe numerical simulations designed to help elucidate the role of ocean salinity in climate. Using a general circulation model, we study a 100-year sensitivity experiment in which the global-mean salinity is doubled from its present observed value, by adding 35 psu everywhere. The salinity increase produces a rapid global-mean sea-surface warming of 0.8◦ within a few years, caused by reduced vertical mixing associated with changes in cabbeling. The warming is followed by a gradual global mean sea-surface cooling of 0.4 ◦C over the next few decades, caused by an increase in the vertical (downward) component of the isopycnal diffusive heat flux. We find no evidence of impacts on the variability of either the Atlantic thermohaline circulation or the El Ni ̃no/Southern Oscillation. The mean strength of the Atlantic meridional overturning is slightly reduced and the North Atlantic Deep Water penetrates less deeply. Nevertheless, our results dispute claims that higher salinities for the world ocean have profound consequences for the thermohaline circulation. In additional experiments with doubled atmospheric carbon dioxide, we find that the amplitude and spatial pattern of the global warming signal are modified in the hypersaline ocean. In particular, the ocean’s contribution to the climate sensitivity is significantly reduced. We infer the existence of a non-linear interaction between the climate responses to modified carbon dioxide and modified salinity.
Type
article
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williams_2009.pdf
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Format
Adobe PDF
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