Ocean stratification and low melt rates at the Ross Ice Shelf grounding zone
Ocean‐driven melting of ice shelves is a primary mechanism for ice loss from Antarctica. However, due to the difficulty in accessing the sub‐ice shelf ocean cavity, the relationship between ice shelf melting and ocean conditions is poorly understood, particularly near the grounding zone, where the i...
Published in: | Journal of Geophysical Research: Oceans |
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2018
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Online Access: | https://eprints.utas.edu.au/28624/ https://eprints.utas.edu.au/28624/1/Begeman_et_al-2018-Journal_of_Geophysical_Research_Oceans.pdf |
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ftunivtasmania:oai:eprints.utas.edu.au:28624 2023-05-15T13:31:53+02:00 Ocean stratification and low melt rates at the Ross Ice Shelf grounding zone Begeman, CB Tulaczyk, SM Marsh, OJ Mikucki, JA Stanton, TP Hodson, TO Siegfried, MR Powell, RD Christianson, K King, MA 2018 application/pdf https://eprints.utas.edu.au/28624/ https://eprints.utas.edu.au/28624/1/Begeman_et_al-2018-Journal_of_Geophysical_Research_Oceans.pdf en eng Wiley-Blackwell Publishing https://eprints.utas.edu.au/28624/1/Begeman_et_al-2018-Journal_of_Geophysical_Research_Oceans.pdf Begeman, CB, Tulaczyk, SM, Marsh, OJ, Mikucki, JA, Stanton, TP, Hodson, TO, Siegfried, MR, Powell, RD, Christianson, K and King, MA orcid:0000-0001-5611-9498 2018 , 'Ocean stratification and low melt rates at the Ross Ice Shelf grounding zone' , Journal of Geophysical Research: Oceans , pp. 1-15 , doi:10.1029/2018JC013987 <http://dx.doi.org/10.1029/2018JC013987>. ice-ocean interactions ice shelf Antarctica double diffusion grounding zone ocean mixing Ross Ice Shelf Article PeerReviewed 2018 ftunivtasmania https://doi.org/10.1029/2018JC013987 2021-09-20T22:16:55Z Ocean‐driven melting of ice shelves is a primary mechanism for ice loss from Antarctica. However, due to the difficulty in accessing the sub‐ice shelf ocean cavity, the relationship between ice shelf melting and ocean conditions is poorly understood, particularly near the grounding zone, where the ice transitions from grounded to floating. We present the first borehole oceanographic observations from the grounding zone of the Ross Ice Shelf, Antarctica's largest ice shelf by area. Contrary to predictions that tidal currents near grounding zones mix the water column, we found that Ross Ice Shelf waters were vertically stratified. Current velocities at middepth in the ocean cavity did not change significantly over measurement periods at two different parts of the tidal cycle. The observed stratification resulted in low melt rates near this portion of the grounding zone, inferred from phase‐sensitive radar observations. These melt rates were generally <10 cm/year, which is lower than average for the Ross Ice Shelf (∼20 cm/year). Melt rates may be higher at portions of the grounding zone that experience higher subglacial discharge or stronger tidal mixing. Stratification in the cavity at the borehole site was prone to diffusive convection as a result of ice shelf melting. Since diffusive convection influences vertical heat and salt fluxes differently than shear‐driven turbulence, this process may affect ice shelf melting and merits further consideration in ocean models of sub‐ice shelf circulation. Article in Journal/Newspaper Antarc* Antarctica Ice Shelf Ice Shelves Ross Ice Shelf University of Tasmania: UTas ePrints Ross Ice Shelf Journal of Geophysical Research: Oceans 123 10 7438 7452 |
institution |
Open Polar |
collection |
University of Tasmania: UTas ePrints |
op_collection_id |
ftunivtasmania |
language |
English |
topic |
ice-ocean interactions ice shelf Antarctica double diffusion grounding zone ocean mixing Ross Ice Shelf |
spellingShingle |
ice-ocean interactions ice shelf Antarctica double diffusion grounding zone ocean mixing Ross Ice Shelf Begeman, CB Tulaczyk, SM Marsh, OJ Mikucki, JA Stanton, TP Hodson, TO Siegfried, MR Powell, RD Christianson, K King, MA Ocean stratification and low melt rates at the Ross Ice Shelf grounding zone |
topic_facet |
ice-ocean interactions ice shelf Antarctica double diffusion grounding zone ocean mixing Ross Ice Shelf |
description |
Ocean‐driven melting of ice shelves is a primary mechanism for ice loss from Antarctica. However, due to the difficulty in accessing the sub‐ice shelf ocean cavity, the relationship between ice shelf melting and ocean conditions is poorly understood, particularly near the grounding zone, where the ice transitions from grounded to floating. We present the first borehole oceanographic observations from the grounding zone of the Ross Ice Shelf, Antarctica's largest ice shelf by area. Contrary to predictions that tidal currents near grounding zones mix the water column, we found that Ross Ice Shelf waters were vertically stratified. Current velocities at middepth in the ocean cavity did not change significantly over measurement periods at two different parts of the tidal cycle. The observed stratification resulted in low melt rates near this portion of the grounding zone, inferred from phase‐sensitive radar observations. These melt rates were generally <10 cm/year, which is lower than average for the Ross Ice Shelf (∼20 cm/year). Melt rates may be higher at portions of the grounding zone that experience higher subglacial discharge or stronger tidal mixing. Stratification in the cavity at the borehole site was prone to diffusive convection as a result of ice shelf melting. Since diffusive convection influences vertical heat and salt fluxes differently than shear‐driven turbulence, this process may affect ice shelf melting and merits further consideration in ocean models of sub‐ice shelf circulation. |
format |
Article in Journal/Newspaper |
author |
Begeman, CB Tulaczyk, SM Marsh, OJ Mikucki, JA Stanton, TP Hodson, TO Siegfried, MR Powell, RD Christianson, K King, MA |
author_facet |
Begeman, CB Tulaczyk, SM Marsh, OJ Mikucki, JA Stanton, TP Hodson, TO Siegfried, MR Powell, RD Christianson, K King, MA |
author_sort |
Begeman, CB |
title |
Ocean stratification and low melt rates at the Ross Ice Shelf grounding zone |
title_short |
Ocean stratification and low melt rates at the Ross Ice Shelf grounding zone |
title_full |
Ocean stratification and low melt rates at the Ross Ice Shelf grounding zone |
title_fullStr |
Ocean stratification and low melt rates at the Ross Ice Shelf grounding zone |
title_full_unstemmed |
Ocean stratification and low melt rates at the Ross Ice Shelf grounding zone |
title_sort |
ocean stratification and low melt rates at the ross ice shelf grounding zone |
publisher |
Wiley-Blackwell Publishing |
publishDate |
2018 |
url |
https://eprints.utas.edu.au/28624/ https://eprints.utas.edu.au/28624/1/Begeman_et_al-2018-Journal_of_Geophysical_Research_Oceans.pdf |
geographic |
Ross Ice Shelf |
geographic_facet |
Ross Ice Shelf |
genre |
Antarc* Antarctica Ice Shelf Ice Shelves Ross Ice Shelf |
genre_facet |
Antarc* Antarctica Ice Shelf Ice Shelves Ross Ice Shelf |
op_relation |
https://eprints.utas.edu.au/28624/1/Begeman_et_al-2018-Journal_of_Geophysical_Research_Oceans.pdf Begeman, CB, Tulaczyk, SM, Marsh, OJ, Mikucki, JA, Stanton, TP, Hodson, TO, Siegfried, MR, Powell, RD, Christianson, K and King, MA orcid:0000-0001-5611-9498 2018 , 'Ocean stratification and low melt rates at the Ross Ice Shelf grounding zone' , Journal of Geophysical Research: Oceans , pp. 1-15 , doi:10.1029/2018JC013987 <http://dx.doi.org/10.1029/2018JC013987>. |
op_doi |
https://doi.org/10.1029/2018JC013987 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
123 |
container_issue |
10 |
container_start_page |
7438 |
op_container_end_page |
7452 |
_version_ |
1766021992875556864 |