Anthropogenic Temperature and Salinity Changes in the Southern Ocean

In this study, we compare observed Southern Ocean temperature and salinity changes with the historical simulations from 13 models from phase 5 of the Coupled Model Intercomparison Project (CMIP5), using an optimal fingerprinting framework. We show that there is an unequivocal greenhouse gas-forced w...

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Bibliographic Details
Published in:Journal of Climate
Main Authors: Hobbs, William R., Roach, Christopher, Roy, Tilla, Sallee, Jean-baptiste, Bindoff, Nathaniel
Format: Article in Journal/Newspaper
Language:English
Published: Amer Meteorological Soc 2021
Subjects:
Ocean
Southern Ocean
Climate change
Coupled models
Model comparison
Antarctic
Antarc*
Online Access:https://archimer.ifremer.fr/doc/00755/86729/92170.pdf
https://archimer.ifremer.fr/doc/00755/86729/92171.pdf
https://doi.org/10.1175/JCLI-D-20-0454.1
https://archimer.ifremer.fr/doc/00755/86729/
Description
Summary:In this study, we compare observed Southern Ocean temperature and salinity changes with the historical simulations from 13 models from phase 5 of the Coupled Model Intercomparison Project (CMIP5), using an optimal fingerprinting framework. We show that there is an unequivocal greenhouse gas-forced warming in the Southern Ocean. This warming is strongest in the Subantarctic Mode Waters but is also detectable in denser water masses, which has not been shown in previous studies. We also find greenhouse gas-forced salinity changes, most notably a freshening of Antarctic Intermediate Waters. Our analysis also shows that non-greenhouse gas anthropogenic forcings-anthropogenic aerosols and stratospheric ozone depletion-have played an important role in mitigating the Southern Ocean's warming. However, the detestability of these responses using optimal fingerprinting is model dependent, and this result is therefore not as robust as for the greenhouse gas response.

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