scholarly journals The Nature and Distribution of Labile Organic Carbon in Sediments Beneath a Collapsed Ice Shelf: Climate Change Effects on the Antarctic Continental Shelf

2022 ◽  
Author(s):  
Richard S Taylor ◽  
David J DeMaster ◽  
Craig R Smith ◽  
Enrique Isla
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Continental Shelf ◽  
Ice Shelf ◽  
Labile Organic Carbon ◽  
Climate Change Effects ◽  
Antarctic Continental Shelf ◽  
The Antarctic

scholarly journals Explicit and parametrised representation of under ice shelf seas in a z<sup>*</sup> coordinate ocean model

2017 ◽  
Author(s):  
Pierre Mathiot ◽  
Adrian Jenkins ◽  
Christopher Harris ◽  
Gurvan Madec
Keyword(s):  
Sea Ice ◽  
Continental Shelf ◽  
Weddell Sea ◽  
Depth Range ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Antarctic Continental Shelf ◽  
Shelf Seas ◽  
Ocean Properties ◽  
The Antarctic

Abstract. Ice shelf/ocean interactions are a major source of fresh water on the Antarctic continental shelf and have a strong impact on ocean properties, ocean circulation and sea ice. However, climate models based on the ocean/sea ice model NEMO currently do not include these interactions in any detail. The capability of explicitly simulating the circulation beneath ice shelves is introduced in the non-linear free surface model NEMO. Its implementation into the NEMO framework and its assessment in an idealised and realistic circum-Antarctic configuration is described in this study. Compared with the current prescription of ice shelf melting (i.e. at the surface) inclusion of open sub-ice-shelf leads to a decrease sea ice thickness along the coast, a weakening of the ocean stratification on the shelf, a decrease in salinity of HSSW on the Ross and Weddell Sea shelves and an increase in the strength of the gyres that circulate within the over-deepened basins on the West Antarctic continental shelf. Mimicking the under ice shelf seas overturning circulation by introducing the meltwater over the depth range of the ice shelf base, rather than at the surface is also tested. It yields similar improvements in the simulated ocean properties and circulation over the Antarctic continental shelf than the explicit ice shelf cavity representation. With the ice shelf cavities opened, the widely-used “3 equations” ice shelf melting formulation enables an interactive computation of melting that has been assessed. Comparison with observational estimates of ice shelf melting indicates realistic results for most ice shelves. However, melting rates for Amery, Getz and George VI ice shelves are considerably overestimated.

scholarly journals Multidecadal warming of Antarctic waters

Science ◽  
2014 ◽  
Vol 346 (6214) ◽  
pp. 1227-1231 ◽  
Author(s):  
Sunke Schmidtko ◽  
Karen J. Heywood ◽  
Andrew F. Thompson ◽  
Shigeru Aoki
Keyword(s):  
Continental Shelf ◽  
Large Scale ◽  
Bottom Water ◽  
Heat Content ◽  
Ice Shelf ◽  
Antarctic Continental Shelf ◽  
Antarctic Waters ◽  
Core Depth ◽  
The Antarctic

Decadal trends in the properties of seawater adjacent to Antarctica are poorly known, and the mechanisms responsible for such changes are uncertain. Antarctic ice sheet mass loss is largely driven by ice shelf basal melt, which is influenced by ocean-ice interactions and has been correlated with Antarctic Continental Shelf Bottom Water (ASBW) temperature. We document the spatial distribution of long-term large-scale trends in temperature, salinity, and core depth over the Antarctic continental shelf and slope. Warming at the seabed in the Bellingshausen and Amundsen seas is linked to increased heat content and to a shoaling of the mid-depth temperature maximum over the continental slope, allowing warmer, saltier water greater access to the shelf in recent years. Regions of ASBW warming are those exhibiting increased ice shelf melt.

scholarly journals Explicit representation and parametrised impacts of under ice shelf seas in the <i>z</i><sup>∗</sup> coordinate ocean model NEMO 3.6

2017 ◽  
Vol 10 (7) ◽  
pp. 2849-2874 ◽  
Author(s):  
Pierre Mathiot ◽  
Adrian Jenkins ◽  
Christopher Harris ◽  
Gurvan Madec
Keyword(s):  
Sea Ice ◽  
Continental Shelf ◽  
Weddell Sea ◽  
Surface Model ◽  
Depth Range ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Antarctic Continental Shelf ◽  
Ocean Properties ◽  
The Antarctic

Abstract. Ice-shelf–ocean interactions are a major source of freshwater on the Antarctic continental shelf and have a strong impact on ocean properties, ocean circulation and sea ice. However, climate models based on the ocean–sea ice model NEMO (Nucleus for European Modelling of the Ocean) currently do not include these interactions in any detail. The capability of explicitly simulating the circulation beneath ice shelves is introduced in the non-linear free surface model NEMO. Its implementation into the NEMO framework and its assessment in an idealised and realistic circum-Antarctic configuration is described in this study. Compared with the current prescription of ice shelf melting (i.e. at the surface), inclusion of open sub-ice-shelf cavities leads to a decrease in sea ice thickness along the coast, a weakening of the ocean stratification on the shelf, a decrease in salinity of high-salinity shelf water on the Ross and Weddell sea shelves and an increase in the strength of the gyres that circulate within the over-deepened basins on the West Antarctic continental shelf. Mimicking the overturning circulation under the ice shelves by introducing a prescribed meltwater flux over the depth range of the ice shelf base, rather than at the surface, is also assessed. It yields similar improvements in the simulated ocean properties and circulation over the Antarctic continental shelf to those from the explicit ice shelf cavity representation. With the ice shelf cavities opened, the widely used three equation ice shelf melting formulation, which enables an interactive computation of melting, is tested. Comparison with observational estimates of ice shelf melting indicates realistic results for most ice shelves. However, melting rates for the Amery, Getz and George VI ice shelves are considerably overestimated.

scholarly journals A new depositional model for ice shelves, based upon sediment cores from the Ross Sea and the MaC. Robertson shelf, Antarctica

1998 ◽  
Vol 27 ◽  
pp. 281-284 ◽  
Author(s):  
Eugene W. Domack ◽  
P.T. Harris
Keyword(s):  
Continental Shelf ◽  
Ross Sea ◽  
Sediment Cores ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Antarctic Continental Shelf ◽  
Late Pleistocene To Holocene ◽  
Ice Shell ◽  
Bottom To Top ◽  
The Antarctic

We document the similarity of depositional facies occurring in gravity cores recovered from two disjunct regions of the Antarctic continental shelf: the Ross Sea and the MaC. Robertson shelf. The facies sequence model is represented in two cores, one collected during the 1995-1 cruise of the R/VNathaniel R. Palmer(core NBP95 TC-18) and the other collected by the RSVAurora Australisduring cruise 149 in 1995 (core 149 39GC38). Both cores show a succession of facies indicative of ice-shelf retreat during the late-Pleistocene to Holocene transition. Distinct lithofacies range in thickness from a few tens of cm to 1 m and consist of (from bottom to top) a coarse, granulated sandy mud; laminated silt and clay; structureless silly clay; poorly sorted sandy siliceous mud; and siliceous mud and ooze. These facies represent the passage of distinct depositional regimes across the core sites, including sub-ice shelf beneath a basal debris zone; sub-ice shell distal to a debris zone; calving-line transition; and open marine. This facies model represents an advance in our understanding of Glacial marine stratigraphy for the Antarctic continental shelf and will provide the basis for more realistic palaeoglacial reconstructions.

Climate change effects on peatland decomposition and porewater dissolved organic carbon biogeochemistry

2016 ◽  
Vol 128 (3) ◽  
pp. 385-396 ◽  
Author(s):  
Catherine M. Dieleman ◽  
Zoë Lindo ◽  
James W. McLaughlin ◽  
Aaron E. Craig ◽  
Brian A. Branfireun
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Climate Change Effects ◽  
Carbon Biogeochemistry

Pathways and timescales of connectivity around the Antarctic continental shelf 

2021 ◽  
Author(s):  
Hannah Dawson ◽  
Adele Morrison ◽  
Veronica Tamsitt ◽  
Matthew England
Keyword(s):  
Continental Shelf ◽  
Ross Sea ◽  
Coastal Current ◽  
West Antarctica ◽  
Source Regions ◽  
Freshwater Forcing ◽  
Antarctic Continental Shelf ◽  
Antarctic Continent ◽  
Antarctic Slope Current ◽  
The Antarctic

&lt;p&gt;&lt;span xml:lang=&quot;EN-US&quot; data-contrast=&quot;auto&quot;&gt;&lt;span&gt;The Antarctic margin is surrounded by two westward flowing currents: the Antarctic Slope Current and the Antarctic Coastal Current. The former influences key processes near the Antarctic margin by regulating the flow of heat and nutrients onto and off the continental shelf, while together they &lt;/span&gt;&lt;/span&gt;&lt;span xml:lang=&quot;EN-US&quot; data-contrast=&quot;auto&quot;&gt;&lt;span&gt;advect&lt;/span&gt;&lt;/span&gt;&lt;span xml:lang=&quot;EN-US&quot; data-contrast=&quot;auto&quot;&gt;&lt;span&gt; nutrients, biological organisms, and temperature and salinity anomalies around the coastline, providing a connective link between different shelf regions. However, the extent to which these currents transport water from one sector of the continental shelf to another, and the timescales over which this occurs, remain poorly understood. Concern that crucial water formation sites around the Antarctic coastline could respond to non-local freshwater forcing &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span xml:lang=&quot;EN-US&quot; data-contrast=&quot;auto&quot;&gt;&lt;span&gt;from ice shel&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span xml:lang=&quot;EN-US&quot; data-contrast=&quot;auto&quot;&gt;&lt;span&gt;f meltwater&lt;/span&gt;&lt;/span&gt;&lt;/span&gt; &lt;span xml:lang=&quot;EN-US&quot; data-contrast=&quot;auto&quot;&gt;&lt;span&gt;motivates a more thorough understanding of zonal connectivity around Antarctica. In this study, we use daily velocity fields from a global high-resolution ocean-sea ice model, combined with the &lt;span&gt;Lagrangian&lt;/span&gt; tracking software Parcels, to investigate the pathways and timescales connecting different regions of the Antarctic continental shelf&lt;span&gt; with a view to understanding&lt;/span&gt;&lt;span&gt; the timescales of meltwater transport around the continent&lt;/span&gt;. Virtual particles are released over the continental shelf, poleward of the 1000 &lt;span&gt;metre&lt;/span&gt; isobath, and are tracked for 20 years. Our results show a strong seasonal cycle connecting different sectors of the Antarctic continent, with more particles arriving further downstream during winter than during summer months. Strong advective links exist between West Antarctica and the Ross Sea while shelf geometry in some other regions acts as barriers to transport. We also highlight the varying importance of the Antarctic Slope Current and Antarctic Coastal Current in connecting different sectors of the coastline. Our results help to improve our understanding of circum-Antarctic connectivity &lt;span&gt;and the timescales &lt;/span&gt;&lt;span&gt;of meltwater transport from source regions to downstream &lt;/span&gt;&lt;span&gt;shelf locations. &lt;/span&gt;&lt;span&gt;Further&lt;/span&gt;&lt;span&gt;more, t&lt;/span&gt;&lt;span&gt;he timescales and pathways we &lt;/span&gt;&lt;span&gt;present &lt;/span&gt;&lt;span&gt;p&lt;/span&gt;rovide a baseline from which to assess long-term changes in Antarctic coastal circulation due to local and remote forcing.&lt;br&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;

scholarly journals Modelled response of the volume and thickness of the Antarctic ice sheet to the advance of the grounded area

2010 ◽  
Vol 51 (55) ◽  
pp. 41-48 ◽  
Author(s):  
Fuyuki Saito ◽  
Ayako Abe-Ouchi
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Volume Change ◽  
Numerical Experiments ◽  
Ice Sheet ◽  
Ice Shelf ◽  
Antarctic Ice Sheet ◽  
Ice Shelves ◽  
Ice Volume ◽  
The Antarctic

AbstractNumerical experiments are performed for the Antarctic ice sheet to study the sensitivity of the ice volume to variations in the area of grounded ice and to changes in the climate during the most recent deglaciation. The effect of the variations in the grounded area is found to be the major source of changes in the ice volume, while the effect of climate change was minor. The maximum possible contribution of the ice-volume change to sea-level rise during the deglaciation is estimated to be 36 m, which covers most values estimated in previous studies. The effect of the advance of the ice-sheet margin over those regions not connected to the major ice shelves contributes one-third of the total ice-volume change, which is comparable to the effect of the grounding of the Filchner–Ronne Ice Shelf and the contribution of the Ross and Amery Ice Shelves together.

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