The Dependence of Internal Multidecadal Variability in the Southern Ocean on the Ocean Background Mean State
: Previous studies have shown the existence of internal multidecadal variability in the Southern Ocean using multiple climate models. This variability, associated with deep ocean convection, can have significant climate impacts. In this work, we use sensitivity studies based on Geophysical Fluid Dyn...
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ftunistlouisbrus:oai:dial.uclouvain.be:boreal:241541 2024-05-12T07:55:50+00:00 The Dependence of Internal Multidecadal Variability in the Southern Ocean on the Ocean Background Mean State Zhang, Liping Delworth, Thomas L. Cooke, William Goosse, Hugues Bushuk, Mitchell Morioka, Yushi Yang, Xiaosong UCL - SST/ELI/ELIC - Earth & Climate 2021 http://hdl.handle.net/2078.1/241541 https://doi.org/10.1175/jcli-d-20-0049.1 eng eng American Meteorological Society boreal:241541 http://hdl.handle.net/2078.1/241541 doi:10.1175/jcli-d-20-0049.1 urn:ISSN:0894-8755 urn:EISSN:1520-0442 info:eu-repo/semantics/openAccess Journal of Climate, Vol. 34, no.3, p. 1061-1080 (2021) Atmospheric Science info:eu-repo/semantics/article 2021 ftunistlouisbrus https://doi.org/10.1175/jcli-d-20-0049.1 2024-04-18T17:20:09Z : Previous studies have shown the existence of internal multidecadal variability in the Southern Ocean using multiple climate models. This variability, associated with deep ocean convection, can have significant climate impacts. In this work, we use sensitivity studies based on Geophysical Fluid Dynamics Laboratory (GFDL) models to investigate the linkage of this internal variability with the background ocean mean state. We find that mean ocean stratification in the subpolar region that is dominated by mean salinity influences whether this variability occurs, as well as its time scale. The weakening of background stratification favors the occurrence of deep convection. For background stratification states in which the low-frequency variability occurs, weaker ocean stratification corresponds to shorter periods of variability and vice versa. The amplitude of convection variability is largely determined by the amount of heat that can accumulate in the subsurface ocean during periods of the oscillation without deep convection. A larger accumulation of heat in the subsurface reservoir corresponds to a larger amplitude of variability. The subsurface heat buildup is a balance between advection that supplies heat to the reservoir and vertical mixing/convection that depletes it. Subsurface heat accumulation can be intensified both by an enhanced horizontal temperature advection by the Weddell Gyre and by an enhanced ocean stratification leading to reduced vertical mixing and surface heat loss. The paleoclimate records over Antarctica indicate that this multidecadal variability has very likely happened in past climates and that the period of this variability may shift with different climate background mean state. Article in Journal/Newspaper Antarc* Antarctica Southern Ocean DIAL@USL-B (Université Saint-Louis, Bruxelles) Southern Ocean Weddell Journal of Climate 34 3 1061 1080 |
institution |
Open Polar |
collection |
DIAL@USL-B (Université Saint-Louis, Bruxelles) |
op_collection_id |
ftunistlouisbrus |
language |
English |
topic |
Atmospheric Science |
spellingShingle |
Atmospheric Science Zhang, Liping Delworth, Thomas L. Cooke, William Goosse, Hugues Bushuk, Mitchell Morioka, Yushi Yang, Xiaosong The Dependence of Internal Multidecadal Variability in the Southern Ocean on the Ocean Background Mean State |
topic_facet |
Atmospheric Science |
description |
: Previous studies have shown the existence of internal multidecadal variability in the Southern Ocean using multiple climate models. This variability, associated with deep ocean convection, can have significant climate impacts. In this work, we use sensitivity studies based on Geophysical Fluid Dynamics Laboratory (GFDL) models to investigate the linkage of this internal variability with the background ocean mean state. We find that mean ocean stratification in the subpolar region that is dominated by mean salinity influences whether this variability occurs, as well as its time scale. The weakening of background stratification favors the occurrence of deep convection. For background stratification states in which the low-frequency variability occurs, weaker ocean stratification corresponds to shorter periods of variability and vice versa. The amplitude of convection variability is largely determined by the amount of heat that can accumulate in the subsurface ocean during periods of the oscillation without deep convection. A larger accumulation of heat in the subsurface reservoir corresponds to a larger amplitude of variability. The subsurface heat buildup is a balance between advection that supplies heat to the reservoir and vertical mixing/convection that depletes it. Subsurface heat accumulation can be intensified both by an enhanced horizontal temperature advection by the Weddell Gyre and by an enhanced ocean stratification leading to reduced vertical mixing and surface heat loss. The paleoclimate records over Antarctica indicate that this multidecadal variability has very likely happened in past climates and that the period of this variability may shift with different climate background mean state. |
author2 |
UCL - SST/ELI/ELIC - Earth & Climate |
format |
Article in Journal/Newspaper |
author |
Zhang, Liping Delworth, Thomas L. Cooke, William Goosse, Hugues Bushuk, Mitchell Morioka, Yushi Yang, Xiaosong |
author_facet |
Zhang, Liping Delworth, Thomas L. Cooke, William Goosse, Hugues Bushuk, Mitchell Morioka, Yushi Yang, Xiaosong |
author_sort |
Zhang, Liping |
title |
The Dependence of Internal Multidecadal Variability in the Southern Ocean on the Ocean Background Mean State |
title_short |
The Dependence of Internal Multidecadal Variability in the Southern Ocean on the Ocean Background Mean State |
title_full |
The Dependence of Internal Multidecadal Variability in the Southern Ocean on the Ocean Background Mean State |
title_fullStr |
The Dependence of Internal Multidecadal Variability in the Southern Ocean on the Ocean Background Mean State |
title_full_unstemmed |
The Dependence of Internal Multidecadal Variability in the Southern Ocean on the Ocean Background Mean State |
title_sort |
dependence of internal multidecadal variability in the southern ocean on the ocean background mean state |
publisher |
American Meteorological Society |
publishDate |
2021 |
url |
http://hdl.handle.net/2078.1/241541 https://doi.org/10.1175/jcli-d-20-0049.1 |
geographic |
Southern Ocean Weddell |
geographic_facet |
Southern Ocean Weddell |
genre |
Antarc* Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctica Southern Ocean |
op_source |
Journal of Climate, Vol. 34, no.3, p. 1061-1080 (2021) |
op_relation |
boreal:241541 http://hdl.handle.net/2078.1/241541 doi:10.1175/jcli-d-20-0049.1 urn:ISSN:0894-8755 urn:EISSN:1520-0442 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1175/jcli-d-20-0049.1 |
container_title |
Journal of Climate |
container_volume |
34 |
container_issue |
3 |
container_start_page |
1061 |
op_container_end_page |
1080 |
_version_ |
1798835706731167744 |