Controlling high-latitude Southern Ocean convection in climate models
Earth System Models (ESMs) generally suffer from a poor simulation of the High-Latitude Southern Ocean (HLSO). Here we aim at a better understanding of the shortcomings by investigating the sensitivity of the HLSO to the external freshwater flux and the horizontal resolution in forced and coupled si...
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ftpubman:oai:pure.mpg.de:item_2082448 2023-08-27T04:04:43+02:00 Controlling high-latitude Southern Ocean convection in climate models Stössel, A. Notz, D. Haumann, F. Haak, H. Jungclaus, J. Mikolajewicz, U. 2015-02-15 http://hdl.handle.net/11858/00-001M-0000-0024-6E53-8 eng eng info:eu-repo/semantics/altIdentifier/doi/10.1016/j.ocemod.2014.11.008 http://hdl.handle.net/11858/00-001M-0000-0024-6E53-8 Ocean Modelling info:eu-repo/semantics/article 2015 ftpubman https://doi.org/10.1016/j.ocemod.2014.11.008 2023-08-02T01:20:26Z Earth System Models (ESMs) generally suffer from a poor simulation of the High-Latitude Southern Ocean (HLSO). Here we aim at a better understanding of the shortcomings by investigating the sensitivity of the HLSO to the external freshwater flux and the horizontal resolution in forced and coupled simulations with the Max-Planck-Institute Ocean Model (MPIOM). Forced experiments reveal an immediate reduction of open-ocean convection with additional freshwater input. The latter leads to a remarkably realistic simulation of the distinct water-mass structure in the central Weddell Sea featuring a temperature maximum of +0.5 °C at 250 m depth. Similar, but more modest improvements occur over a time span of 40 years after switching from a forced to a coupled simulation with an eddy-resolving version of MPIOM. The switch is accompanied with pronounced changes of the external freshwater flux and the wind field, as well as a more realistic heat flux due to coupling. Similar to the forced freshwater-flux experiments, a heat reservoir develops at depth, which in turn decreases the vertically integrated density of the HLSO and reduces the Antarctic Circumpolar Current to rather realistic values. Coupling with a higher resolution version of the atmosphere model (ECHAM6) yields distinct improvements of the HLSO water-mass structure and sea-ice cover. While the coupled simulations reveal a realistic amount of Antarctic runoff, its distribution appears too concentrated along the coast. Spreading the runoff over a wider region, as suggested in earlier studies to mimic the effect of freshwater transport through icebergs, also leads to noticeable improvements of the HLSO water-mass properties, predominantly along the coast. This suggests that the spread of the runoff improves the representation of Antarctic Bottom Water formation through enhanced near-boundary convection rather than weakened open-ocean convection. Article in Journal/Newspaper Antarc* Antarctic Iceberg* Sea ice Southern Ocean Weddell Sea Max Planck Society: MPG.PuRe Antarctic Southern Ocean The Antarctic Weddell Sea Weddell Ocean Modelling 86 58 75 |
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Max Planck Society: MPG.PuRe |
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ftpubman |
language |
English |
description |
Earth System Models (ESMs) generally suffer from a poor simulation of the High-Latitude Southern Ocean (HLSO). Here we aim at a better understanding of the shortcomings by investigating the sensitivity of the HLSO to the external freshwater flux and the horizontal resolution in forced and coupled simulations with the Max-Planck-Institute Ocean Model (MPIOM). Forced experiments reveal an immediate reduction of open-ocean convection with additional freshwater input. The latter leads to a remarkably realistic simulation of the distinct water-mass structure in the central Weddell Sea featuring a temperature maximum of +0.5 °C at 250 m depth. Similar, but more modest improvements occur over a time span of 40 years after switching from a forced to a coupled simulation with an eddy-resolving version of MPIOM. The switch is accompanied with pronounced changes of the external freshwater flux and the wind field, as well as a more realistic heat flux due to coupling. Similar to the forced freshwater-flux experiments, a heat reservoir develops at depth, which in turn decreases the vertically integrated density of the HLSO and reduces the Antarctic Circumpolar Current to rather realistic values. Coupling with a higher resolution version of the atmosphere model (ECHAM6) yields distinct improvements of the HLSO water-mass structure and sea-ice cover. While the coupled simulations reveal a realistic amount of Antarctic runoff, its distribution appears too concentrated along the coast. Spreading the runoff over a wider region, as suggested in earlier studies to mimic the effect of freshwater transport through icebergs, also leads to noticeable improvements of the HLSO water-mass properties, predominantly along the coast. This suggests that the spread of the runoff improves the representation of Antarctic Bottom Water formation through enhanced near-boundary convection rather than weakened open-ocean convection. |
format |
Article in Journal/Newspaper |
author |
Stössel, A. Notz, D. Haumann, F. Haak, H. Jungclaus, J. Mikolajewicz, U. |
spellingShingle |
Stössel, A. Notz, D. Haumann, F. Haak, H. Jungclaus, J. Mikolajewicz, U. Controlling high-latitude Southern Ocean convection in climate models |
author_facet |
Stössel, A. Notz, D. Haumann, F. Haak, H. Jungclaus, J. Mikolajewicz, U. |
author_sort |
Stössel, A. |
title |
Controlling high-latitude Southern Ocean convection in climate models |
title_short |
Controlling high-latitude Southern Ocean convection in climate models |
title_full |
Controlling high-latitude Southern Ocean convection in climate models |
title_fullStr |
Controlling high-latitude Southern Ocean convection in climate models |
title_full_unstemmed |
Controlling high-latitude Southern Ocean convection in climate models |
title_sort |
controlling high-latitude southern ocean convection in climate models |
publishDate |
2015 |
url |
http://hdl.handle.net/11858/00-001M-0000-0024-6E53-8 |
geographic |
Antarctic Southern Ocean The Antarctic Weddell Sea Weddell |
geographic_facet |
Antarctic Southern Ocean The Antarctic Weddell Sea Weddell |
genre |
Antarc* Antarctic Iceberg* Sea ice Southern Ocean Weddell Sea |
genre_facet |
Antarc* Antarctic Iceberg* Sea ice Southern Ocean Weddell Sea |
op_source |
Ocean Modelling |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.ocemod.2014.11.008 http://hdl.handle.net/11858/00-001M-0000-0024-6E53-8 |
op_doi |
https://doi.org/10.1016/j.ocemod.2014.11.008 |
container_title |
Ocean Modelling |
container_volume |
86 |
container_start_page |
58 |
op_container_end_page |
75 |
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1775352999425605632 |