Polynya-Mediated Southern Ocean Convection: Mechanisms and Response to Climate
2018 Ocean Sciences Meeting, 11-16 February, in Portland, Oregon Many climate models show strong variability in preindustrial Southern Ocean (SO) sea surface temperatures (as well as heat fluxes, sea-ice, salinity, and mixed layer depths) associated with open-ocean deep convection through polynyas....
Main Authors: | , , , , |
---|---|
Format: | Still Image |
Language: | unknown |
Published: |
American Geophysical Union
2018
|
Subjects: | |
Online Access: | http://hdl.handle.net/10261/186030 |
id |
ftcsic:oai:digital.csic.es:10261/186030 |
---|---|
record_format |
openpolar |
spelling |
ftcsic:oai:digital.csic.es:10261/186030 2024-02-11T09:58:05+01:00 Polynya-Mediated Southern Ocean Convection: Mechanisms and Response to Climate Soucie, John Edward San Marinov, I. Cabré Albos, Anna Gnanadesikan, Anand Asadieh, Behzad Asadieh 2018-02 http://hdl.handle.net/10261/186030 unknown American Geophysical Union Association for the Sciences of Limnology and Oceanography https://agu.confex.com/agu/os18/meetingapp.cgi/Paper/326624 Sí 2018 Ocean Sciences Meeting (2018) http://hdl.handle.net/10261/186030 none póster de congreso http://purl.org/coar/resource_type/c_6670 2018 ftcsic 2024-01-16T10:41:21Z 2018 Ocean Sciences Meeting, 11-16 February, in Portland, Oregon Many climate models show strong variability in preindustrial Southern Ocean (SO) sea surface temperatures (as well as heat fluxes, sea-ice, salinity, and mixed layer depths) associated with open-ocean deep convection through polynyas. The CM2MC model, a coarse-resolution 3° version of GFDL’s ESM2M model, demonstrates regular multi-decadal variability of SO open-sea convection in a 5000-year-long control simulation. Under climate-driven freshening of the surface Southern Ocean, polynya-mediated convection shuts down. We explore the mechanisms for regular SO convection—and its climate-driven shutdown—by analyzing results from 3-member ensembles of a long control simulation, historical and RCP8.5 scenarios up to the year 2100, a SO wind increase experiment, and a SO freshwater hosing experiment. We hypothesize that this regular SO variability is primarily driven by a shallow preconditioning mechanism, where near-surface density anomalies induce destratification of the water column at the site of polynya formation. We also explore a simple 2 layer and sea-ice column model to understand this convective oscillation. We hypothesize that a delicate equilibrium between warming from CDW, cooling from the atmosphere, and freshening from ice dynamics can explain the emerging time-scales of internal oscillation in the system. SO water mass formation is significantly impacted by variability in convection. We propose that Antarctic Bottom Water (AABW) formation and the Antarctic Circumpolar Current (ACC) increase in decades with strong convection, while Antarctic Intermediate Water (AAIW) decreases. An analysis of the oceanic implications of a permanent shutdown of convection with climate warming (and under freshwater hosing) shows AABW formation drastically decreasing, along with complex behavior of the intermediate and mode waters. The AABW and AAIW also serve as teleconnections pathways for northward propagation of temperature and salinity anomaly signals, ... Still Image Antarc* Antarctic Sea ice Southern Ocean Digital.CSIC (Spanish National Research Council) Antarctic Southern Ocean The Antarctic |
institution |
Open Polar |
collection |
Digital.CSIC (Spanish National Research Council) |
op_collection_id |
ftcsic |
language |
unknown |
description |
2018 Ocean Sciences Meeting, 11-16 February, in Portland, Oregon Many climate models show strong variability in preindustrial Southern Ocean (SO) sea surface temperatures (as well as heat fluxes, sea-ice, salinity, and mixed layer depths) associated with open-ocean deep convection through polynyas. The CM2MC model, a coarse-resolution 3° version of GFDL’s ESM2M model, demonstrates regular multi-decadal variability of SO open-sea convection in a 5000-year-long control simulation. Under climate-driven freshening of the surface Southern Ocean, polynya-mediated convection shuts down. We explore the mechanisms for regular SO convection—and its climate-driven shutdown—by analyzing results from 3-member ensembles of a long control simulation, historical and RCP8.5 scenarios up to the year 2100, a SO wind increase experiment, and a SO freshwater hosing experiment. We hypothesize that this regular SO variability is primarily driven by a shallow preconditioning mechanism, where near-surface density anomalies induce destratification of the water column at the site of polynya formation. We also explore a simple 2 layer and sea-ice column model to understand this convective oscillation. We hypothesize that a delicate equilibrium between warming from CDW, cooling from the atmosphere, and freshening from ice dynamics can explain the emerging time-scales of internal oscillation in the system. SO water mass formation is significantly impacted by variability in convection. We propose that Antarctic Bottom Water (AABW) formation and the Antarctic Circumpolar Current (ACC) increase in decades with strong convection, while Antarctic Intermediate Water (AAIW) decreases. An analysis of the oceanic implications of a permanent shutdown of convection with climate warming (and under freshwater hosing) shows AABW formation drastically decreasing, along with complex behavior of the intermediate and mode waters. The AABW and AAIW also serve as teleconnections pathways for northward propagation of temperature and salinity anomaly signals, ... |
format |
Still Image |
author |
Soucie, John Edward San Marinov, I. Cabré Albos, Anna Gnanadesikan, Anand Asadieh, Behzad Asadieh |
spellingShingle |
Soucie, John Edward San Marinov, I. Cabré Albos, Anna Gnanadesikan, Anand Asadieh, Behzad Asadieh Polynya-Mediated Southern Ocean Convection: Mechanisms and Response to Climate |
author_facet |
Soucie, John Edward San Marinov, I. Cabré Albos, Anna Gnanadesikan, Anand Asadieh, Behzad Asadieh |
author_sort |
Soucie, John Edward San |
title |
Polynya-Mediated Southern Ocean Convection: Mechanisms and Response to Climate |
title_short |
Polynya-Mediated Southern Ocean Convection: Mechanisms and Response to Climate |
title_full |
Polynya-Mediated Southern Ocean Convection: Mechanisms and Response to Climate |
title_fullStr |
Polynya-Mediated Southern Ocean Convection: Mechanisms and Response to Climate |
title_full_unstemmed |
Polynya-Mediated Southern Ocean Convection: Mechanisms and Response to Climate |
title_sort |
polynya-mediated southern ocean convection: mechanisms and response to climate |
publisher |
American Geophysical Union |
publishDate |
2018 |
url |
http://hdl.handle.net/10261/186030 |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Sea ice Southern Ocean |
op_relation |
https://agu.confex.com/agu/os18/meetingapp.cgi/Paper/326624 Sí 2018 Ocean Sciences Meeting (2018) http://hdl.handle.net/10261/186030 |
op_rights |
none |
_version_ |
1790593667183935488 |