Variability of the Antarctic Coastal Current in the Amundsen Sea

Kim, Chang-Sin; Kim, Tae‐Wan; Cho, Kyoung‐Ho; Ha, Ho Kyung; Lee, Sanghoon; Kim, Hyuncheol; Lee, Jae-Hak

doi:10.1016/j.ecss.2016.08.004

Cited by 34 publications

(46 citation statements)

References 38 publications

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“…Consequently, the pressure gradient between the continental shelf and slope increases, leading to a geostrophic acceleration of the throughflow. This is in line with slope current variability elsewhere around Antarctica (Mathiot et al, 2011;Núñez-Riboni & Fahrbach, 2009), although baroclinic effects may also be substantial (Kim et al, 2016). Those anomalies originating in the Bellingshausen Sea (Figures 3a and 3b) follow f/H contours in accordance with barotropic southern mode dynamics (Hughes et al, 1999).…”

Section: Discussionsupporting

confidence: 78%

“…Those anomalies originating in the Bellingshausen Sea (Figures 3a and 3b) follow f/H contours in accordance with barotropic southern mode dynamics (Hughes et al, 1999). This is in line with slope current variability elsewhere around Antarctica (Mathiot et al, 2011;Núñez-Riboni & Fahrbach, 2009), although baroclinic effects may also be substantial (Kim et al, 2016). The throughflow and BT correlate at r = 0.49, indicating a significant level of covariance.…”

Section: Discussionsupporting

confidence: 74%

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Variability of the Ross Gyre, Southern Ocean: Drivers and Responses Revealed by Satellite Altimetry

Dotto

Garabato

Bacon

et al. 2018

Geophysical Research Letters

113

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Year‐round variability in the Ross Gyre (RG), Antarctica, during 2011–2015, is derived using radar altimetry. The RG is characterized by a bounded recirculating component and a westward throughflow to the south. Two modes of variability of the sea surface height and ocean surface stress curl are revealed. The first represents a large‐scale sea surface height change forced by the Antarctic Oscillation. The second represents semiannual variability in gyre area and strength, driven by fluctuations in sea level pressure associated with the Amundsen Sea Low. Variability in the throughflow is also linked to the Amundsen Sea Low. An adequate description of the oceanic circulation is achieved only when sea ice drag is accounted for in the ocean surface stress. The drivers of RG variability elucidated here have significant implications for our understanding of the oceanic forcing of Antarctic Ice Sheet melting and for the downstream propagation of its ocean freshening footprint.

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Section: Discussionsupporting

confidence: 78%

Section: Discussionsupporting

confidence: 74%

Variability of the Ross Gyre, Southern Ocean: Drivers and Responses Revealed by Satellite Altimetry

Dotto

Garabato

Bacon

et al. 2018

Geophysical Research Letters

113

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“…2). Biotite grains from site 41 were picked from a smaller size-fraction (Table 2) and hence could potentially be influenced by ocean current transport due to fast flow speeds detected off the Dotson Ice Shelf (Kim et al, 2016a). However, 40 Ar/ 39 Ar ages from this sample do not reveal any pattern deviating from that of 40 Ar/ 39 Ar ages in nearby core samples (Table S1).…”

Section: Accepted Manuscriptmentioning

confidence: 93%

“…In the Pacific sector of the Southern Ocean, deep warm water upwells onto the continental shelf ( Fig. 2 inset), locally protrudes towards the coast via bathymetric cross-shelf troughs, which were eroded by WAIS advances during past ice ages, and causes the bases of floating ice shelves to (Kim et al, 2016a). These velocities will become important when discussing transport pathways of detrital mineral grains later on.…”

Section: Oceanographymentioning

confidence: 99%

Geochemical fingerprints of glacially eroded bedrock from West Antarctica: Detrital thermochronology, radiogenic isotope systematics and trace element geochemistry in Late Holocene glacial-marine sediments

Pereira

Flierdt

Hemming

et al. 2018

Earth-Science Reviews

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2018). Geochemical ngerprints of glacially eroded bedrock from West Antarctica: Detrital thermochronology, radiogenic isotope systematics and trace element geochemistry in Late Holocene glacial-marine sediments. Earth-Science Reviews, 182 pp. 204-232.For guidance on citations see FAQs. fingerprints of glacially eroded bedrock from West Antarctica: Detrital thermochronology, radiogenic isotope systematics and trace element geochemistry in Late Holocene glacial-marine sediments. AbstractGeochemical provenance studies of glacial-marine sediments provide a powerful approach to describe subglacial geology, sediment transport pathways, and past ice sheet dynamics. The marinebased West Antarctic Ice Sheet (WAIS) is considered highly vulnerable to ocean warming and sea level rise that is likely to cause its rapid and irreversible retreat. Studies of its past response to climate change are hence essential for projecting its future behaviour. The application of radiogenic and trace element provenance studies for past ice sheet reconstructions requires surveying the geographic variability of geochemical compositions of glaciomarine sediments. In this study, we characterize the provenance of the detrital fraction of 67 Late Holocene marine sediment samples collected off the Pacific margin of West Antarctica (60°W to 160°W), including 40 Ar/ 39 Ar ages of individual hornblende and biotite grains (>150μm), as well as Sr and Nd isotope and trace element composition of the fine-grained (<63μm) sediment fraction. Overall, this approach allows differentiating West Antarctica into five source regions: the Antarctic Peninsula, Bellingshausen Sea, Amundsen Sea, Wrigley Gulf-Hobbs Coast and Sulzberger Bay. Minor geochemical variability is found within each individual sector due to local variability in onland geology. 40 Ar/ 39 Ar ages of icebergrafted hornblende and biotite grains record primarily Carboniferous to Lates Quaternary ages (~0 to 380 Ma), with a notable age peak of ~100 Ma, associated with plutonic intrusions or deformation events during the mid-Cretaceous. Permian-Jurassic 40 Ar/ 39 Ar ages are widespread in the Amundsen Sea sector, marking episodes of large-volume magmatism along the long-lived continental margin.Metasedimentary rocks and Late Cenozoic alkali basalts in West Antarctica cannot be detected using detrital hornblende and biotite 40 Ar/ 39 Ar ages due to the absence or small grain-size (i.e. <150μm) of these minerals in such rocks. These sources can however be readily recognized by their fine-grained geochemical composition. In addition, geographic trends in the provenance from proximal to distal sites provide insights into major sediment transport pathways. While the transport of fine-grained detritus follows bathymetric cross-shelf troughs, the distribution of iceberg-rafted grains shows

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“…This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. As a result of the sSO's environmental challenges to conventional observational approaches, our understanding of the regional ocean dynamics remains fragmentary and is founded primarily on a few long-term mooring records (Daae et al, 2018;Graham et al, 2013;Kim et al, 2016;Núñez-Riboni & Fahrbach, 2009;Peña-Molino et al, 2016;Webber et al, 2017) and numerical models (Kimura et al, 2017;Mathiot et al, 2011;Paloczy et al, 2018;Stewart & Thompson, 2015) as well as sparse hydrographic data (Hatterman, 2018;Mallett et al, 2018). These studies indicate that in many areas around Antarctica, the slope frontal system and on-shelf pycnocline exhibit pronounced seasonality, with wind forcing being consistently suggested as the primary causal factor.…”

Section: Introductionmentioning

confidence: 99%

Phased Response of the Subpolar Southern Ocean to Changes in Circumpolar Winds

Garabato

Dotto

Hooley

et al. 2019

Geophysical Research Letters

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The response of the subpolar Southern Ocean (sSO) to wind forcing is assessed using satellite radar altimetry. sSO sea level exhibits a phased, zonally coherent, bimodal adjustment to circumpolar wind changes, involving comparable seasonal and interannual variations. The adjustment is effected via a quasi‐instantaneous exchange of mass between the Antarctic continental shelf and the sSO to the north, and a 2‐month‐delayed transfer of mass between the wider Southern Ocean and the subtropics. Both adjustment modes are consistent with an Ekman‐mediated response to variations in surface stress. Only the fast mode projects significantly onto the surface geostrophic flow of the sSO; thus, the regional circulation varies in phase with the leading edge of sSO sea level variability. The surface forcing of changes in the sSO system is partly associated with variations of surface winds linked to the Southern Annular Mode and is modulated by sea ice cover near Antarctica.

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Variability of the Antarctic Coastal Current in the Amundsen Sea

Cited by 34 publications

References 38 publications

Variability of the Ross Gyre, Southern Ocean: Drivers and Responses Revealed by Satellite Altimetry

Variability of the Ross Gyre, Southern Ocean: Drivers and Responses Revealed by Satellite Altimetry

Geochemical fingerprints of glacially eroded bedrock from West Antarctica: Detrital thermochronology, radiogenic isotope systematics and trace element geochemistry in Late Holocene glacial-marine sediments

Phased Response of the Subpolar Southern Ocean to Changes in Circumpolar Winds

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