scholarly journals Report Viewgraphs for IC project: Is high resolution or a more realistic bathymetry necessary to simulate Maud Rise polynyas in the Southern Ocean?

2021 ◽  
Author(s):  
Carmela Veneziani
Keyword(s):  
High Resolution ◽  
Southern Ocean ◽  
Maud Rise

scholarly journals Multidecadal preconditioning of the Maud Rise polynya region

Ocean Science ◽  
2020 ◽  
Vol 16 (6) ◽  
pp. 1443-1457
Author(s):  
René M. van Westen ◽  
Henk A. Dijkstra
Keyword(s):  
High Resolution ◽  
Southern Ocean ◽  
Large Scale ◽  
Heat Content ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Model Resolution ◽  
Community Earth System Model ◽  
Maud Rise

Abstract. In this paper, we consider Maud Rise polynya formation in a long (250-year) high-resolution (ocean 0.1∘, atmosphere 0.5∘ horizontal model resolution) of the Community Earth System Model. We find a dominant multidecadal timescale in the occurrence of these Maud Rise polynyas. Analysis of the results leads us to the interpretation that a preferred timescale can be induced by the variability of the Weddell Gyre, previously identified as the Southern Ocean Mode. The large-scale pattern of heat content variability associated with the Southern Ocean Mode modifies the stratification in the Maud Rise region and leads to a preferred timescale in convection through preconditioning of the subsurface density and consequently to polynya formation.

scholarly journals Multidecadal Preconditioning of the Maud Rise Polynya Region

2020 ◽  
Author(s):  
René M. van Westen ◽  
Henk A. Dijkstra
Keyword(s):  
High Resolution ◽  
Southern Ocean ◽  
Time Scale ◽  
Large Scale ◽  
Heat Content ◽  
System Model ◽  
Earth System ◽  
Model Resolution ◽  
Community Earth System Model ◽  
Maud Rise

Abstract. In this paper, we consider Maud Rise polynya formation in a long (250 years) high-resolution (ocean 0.1°, atmosphere 0.5° horizontal model resolution) of the Community Earth System Model. We find a dominant multidecadal time scale in the occurrence of these Maud Rise polynyas. Analysis of the results leads us to the interpretation that a preferred time scale can be induced by the variability of the Weddell Gyre, previously identified as the Southern Ocean Mode. The large-scale pattern of heat content variability associated with the Southern Ocean Mode modifies the stratification in the Maud Rise region and leads to a preferred time scale in convection through preconditioning of the subsurface density, and consequently to polynya formation.

scholarly journals Centennial mineral dust variability in high-resolution ice core data from Dome C, Antarctica

2012 ◽  
Vol 8 (2) ◽  
pp. 609-623 ◽  
Author(s):  
F. Lambert ◽  
M. Bigler ◽  
J. P. Steffensen ◽  
M. Hutterli ◽  
H. Fischer
Keyword(s):  
High Resolution ◽  
Southern Ocean ◽  
Mineral Dust ◽  
Ice Core ◽  
Principal Component ◽  
Dominant Factor ◽  
Core Data ◽  
The Past ◽  
Dust Flux ◽  
Soluble Calcium

Abstract. Ice core data from Antarctica provide detailed insights into the characteristics of past climate, atmospheric circulation, as well as changes in the aerosol load of the atmosphere. We present high-resolution records of soluble calcium (Ca2+), non-sea-salt soluble calcium (nssCa2+), and particulate mineral dust aerosol from the East Antarctic Plateau at a depth resolution of 1 cm, spanning the past 800 000 years. Despite the fact that all three parameters are largely dust-derived, the ratio of nssCa2+ to particulate dust is dependent on the particulate dust concentration itself. We used principal component analysis to extract the joint climatic signal and produce a common high-resolution record of dust flux. This new record is used to identify Antarctic warming events during the past eight glacial periods. The phasing of dust flux and CO2 changes during glacial-interglacial transitions reveals that iron fertilization of the Southern Ocean during the past nine glacial terminations was not the dominant factor in the deglacial rise of CO2 concentrations. Rapid changes in dust flux during glacial terminations and Antarctic warming events point to a rapid response of the southern westerly wind belt in the region of southern South American dust sources on changing climate conditions. The clear lead of these dust changes on temperature rise suggests that an atmospheric reorganization occurred in the Southern Hemisphere before the Southern Ocean warmed significantly.

Southern Ocean Macrostylidae reviewed with a key to the species and new descriptions from Maud Rise

Zootaxa ◽  
2013 ◽  
Vol 3692 (1) ◽  
pp. 160 ◽  
Author(s):  
TORBEN RIEHL ◽  
ANGELIKA BRANDT
Keyword(s):  
Southern Ocean ◽  
Maud Rise

scholarly journals Diatom ooze—A large marine mercury sink

Science ◽  
2018 ◽  
Vol 361 (6404) ◽  
pp. 797-800 ◽  
Author(s):  
Sara Zaferani ◽  
Marta Pérez-Rodríguez ◽  
Harald Biester
Keyword(s):  
High Resolution ◽  
Southern Ocean ◽  
Marine Sediment ◽  
Crucial Role ◽  
Anthropogenic Pollution ◽  
Atmospheric Mercury ◽  
Mercury Accumulation ◽  
Accumulation Rates ◽  
Sediment Data

The role of algae for sequestration of atmospheric mercury in the ocean is largely unknown owing to a lack of marine sediment data. We used high-resolution cores from marine Antarctica to estimate Holocene global mercury accumulation in biogenic siliceous sediments (diatom ooze). Diatom ooze exhibits the highest mercury accumulation rates ever reported for the marine environment and provides a large sink of anthropogenic mercury, surpassing existing model estimates by as much as a factor of 7. Anthropogenic pollution of the Southern Ocean began ~150 years ago, and up to 20% of anthropogenic mercury emitted to the atmosphere may have been stored in diatom ooze. These findings reveal the crucial role of diatoms as a fast vector for mercury sequestration and diatom ooze as a large marine mercury sink.

scholarly journals Southern Ocean Deep Circulation and Heat Uptake in a High-Resolution Climate Model

2016 ◽  
Vol 29 (7) ◽  
pp. 2597-2619 ◽  
Author(s):  
Emily R. Newsom ◽  
Cecilia M. Bitz ◽  
Frank O. Bryan ◽  
Ryan Abernathey ◽  
Peter R. Gent
Keyword(s):  
High Resolution ◽  
Southern Ocean ◽  
Sea Ice ◽  
Climate Model ◽  
Water Mass ◽  
Global Climate Model ◽  
Substantial Reduction ◽  
Meridional Overturning Circulation ◽  
Heat Uptake ◽  
Water Mass Transformation

Abstract The dynamics of the lower cell of the meridional overturning circulation (MOC) in the Southern Ocean are compared in two versions of a global climate model: one with high-resolution (0.1°) ocean and sea ice and the other a lower-resolution (1.0°) counterpart. In the high-resolution version, the lower cell circulation is stronger and extends farther northward into the abyssal ocean. Using the water-mass-transformation framework, it is shown that the differences in the lower cell circulation between resolutions are explained by greater rates of surface water-mass transformation within the higher-resolution Antarctic sea ice pack and by differences in diapycnal-mixing-induced transformation in the abyssal ocean. While both surface and interior transformation processes work in tandem to sustain the lower cell in the control climate, the circulation is far more sensitive to changes in surface transformation in response to atmospheric warming from raising carbon dioxide levels. The substantial reduction in overturning is primarily attributed to reduced surface heat loss. At high resolution, the circulation slows more dramatically, with an anomaly that reaches deeper into the abyssal ocean and alters the distribution of Southern Ocean warming. The resolution dependence of associated heat uptake is particularly pronounced in the abyssal ocean (below 4000 m), where the higher-resolution version of the model warms 4.5 times more than its lower-resolution counterpart.

A new method for characterising the Antarctic Circumpolar Currents using Argo float temperature and salinity profiles

2020 ◽  
Author(s):  
Luke Roberts ◽  
Rhiannon Jones ◽  
Matthew Donnelly ◽  
Katharine Hendry
Keyword(s):  
High Resolution ◽  
Southern Ocean ◽  
Data Processing ◽  
Rapid Development ◽  
Regional Scale ◽  
Global Ocean ◽  
Argo Float ◽  
Oceanographic Data ◽  
The University ◽  
The Antarctic

<p>Argo is an array of automated profiling floats, which have allowed the rapid development of high-resolution and high-quality oceanographic data acquisition. The international program has been in operation since the 1990s providing continuous hydrographic data globally. There are now over a million individual float profiles, contributing to our understanding of global ocean physical properties, such as circulation processes at both a local and regional scale. With these innovations come the challenges of data processing, and compilation of user-friendly data products. For example, the Southern Ocean is a critical region that modulates our climate, via heat exchange, carbon storage, biogeochemistry, and primary productivity. An improved quantified understanding of Southern Ocean currents, informed by Argo, must be implemented in policy-relevant high-resolution climate models to advance our understanding of future change.</p><p> </p><p>In May 2019, a new collaboration was formed between the Southern Ocean Argo Resource Centre (British Oceanographic Data Centre) and the University of Bristol. The aims were two-fold: to produce a method for characterising Southern Ocean frontal zones using Argo floats, and to train early career researchers in the University sector in data processing and management. We have created a publicly available code that characterises physical features of the Antarctic Circumpolar Current using Argo float profiles, using minimal software, and without the need to access high-performance computers. The code categorises each profile based on the temperature and salinity ‘fingerprints’ of zones between each Southern Ocean front. This allows the user to produce output surface plots from user-specified time-slices and geographic areas, and so compare frontal movement in time and space.</p>

Sign in / Sign up

Export Citation Format

Share Document