Spatial and temporal variations in basal melting at Nivlisen ice shelf, East Antarctica, derived from phase-sensitive radars
Thinning rates of ice shelves vary widely around Antarctica, and basal melting is a major component of ice shelf mass loss. In this study, we present records of basal melting at a unique spatial and temporal resolution for East Antarctica, derived from autonomous phase-sensitive radars. These record...
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ftcopernicus:oai:publications.copernicus.org:tc76507 2023-05-15T13:55:28+02:00 Spatial and temporal variations in basal melting at Nivlisen ice shelf, East Antarctica, derived from phase-sensitive radars Lindbäck, Katrin Moholdt, Geir Nicholls, Keith W. Hattermann, Tore Pratap, Bhanu Thamban, Meloth Matsuoka, Kenichi 2019-10-02 application/pdf https://doi.org/10.5194/tc-13-2579-2019 https://tc.copernicus.org/articles/13/2579/2019/ eng eng doi:10.5194/tc-13-2579-2019 https://tc.copernicus.org/articles/13/2579/2019/ eISSN: 1994-0424 Text 2019 ftcopernicus https://doi.org/10.5194/tc-13-2579-2019 2020-07-20T16:22:37Z Thinning rates of ice shelves vary widely around Antarctica, and basal melting is a major component of ice shelf mass loss. In this study, we present records of basal melting at a unique spatial and temporal resolution for East Antarctica, derived from autonomous phase-sensitive radars. These records show spatial and temporal variations of basal melting in 2017 and 2018 at Nivlisen, an ice shelf in central Dronning Maud Land. The annually averaged basal melt rates are in general moderate ( ∼0.8 m yr −1 ). Radar profiling of the ice shelf shows variable ice thickness from smooth beds to basal crevasses and channels. The highest basal melt rates (3.9 m yr −1 ) were observed close to a grounded feature near the ice shelf front. Daily time-varying measurements reveal a seasonal melt signal 4 km from the ice shelf front, at an ice draft of 130 m, where the highest daily basal melt rates occurred in summer (up to 5.6 m yr −1 ). In comparison with wind, air temperatures, and sea ice cover from reanalysis and satellite data, the seasonality in basal melt rates indicates that summer-warmed ocean surface water was pushed by wind beneath the ice shelf front. We observed a different melt regime 35 km into the ice shelf cavity, at an ice draft of 280 m, with considerably lower basal melt rates (annual average of 0.4 m yr −1 ) and no seasonality. We conclude that warm deep-ocean water at present has a limited effect on the basal melting of Nivlisen. On the other hand, a warming in surface waters, as a result of diminishing sea ice cover, has the potential to increase basal melting near the ice shelf front. Continuous in situ monitoring of Antarctic ice shelves is needed to understand the complex mechanisms involved in ice shelf–ocean interactions. Text Antarc* Antarctic Antarctica Dronning Maud Land East Antarctica Ice Shelf Ice Shelves Sea ice Copernicus Publications: E-Journals Antarctic Dronning Maud Land East Antarctica Nivlisen ENVELOPE(11.000,11.000,-70.333,-70.333) The Cryosphere 13 10 2579 2595 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Thinning rates of ice shelves vary widely around Antarctica, and basal melting is a major component of ice shelf mass loss. In this study, we present records of basal melting at a unique spatial and temporal resolution for East Antarctica, derived from autonomous phase-sensitive radars. These records show spatial and temporal variations of basal melting in 2017 and 2018 at Nivlisen, an ice shelf in central Dronning Maud Land. The annually averaged basal melt rates are in general moderate ( ∼0.8 m yr −1 ). Radar profiling of the ice shelf shows variable ice thickness from smooth beds to basal crevasses and channels. The highest basal melt rates (3.9 m yr −1 ) were observed close to a grounded feature near the ice shelf front. Daily time-varying measurements reveal a seasonal melt signal 4 km from the ice shelf front, at an ice draft of 130 m, where the highest daily basal melt rates occurred in summer (up to 5.6 m yr −1 ). In comparison with wind, air temperatures, and sea ice cover from reanalysis and satellite data, the seasonality in basal melt rates indicates that summer-warmed ocean surface water was pushed by wind beneath the ice shelf front. We observed a different melt regime 35 km into the ice shelf cavity, at an ice draft of 280 m, with considerably lower basal melt rates (annual average of 0.4 m yr −1 ) and no seasonality. We conclude that warm deep-ocean water at present has a limited effect on the basal melting of Nivlisen. On the other hand, a warming in surface waters, as a result of diminishing sea ice cover, has the potential to increase basal melting near the ice shelf front. Continuous in situ monitoring of Antarctic ice shelves is needed to understand the complex mechanisms involved in ice shelf–ocean interactions. |
format |
Text |
author |
Lindbäck, Katrin Moholdt, Geir Nicholls, Keith W. Hattermann, Tore Pratap, Bhanu Thamban, Meloth Matsuoka, Kenichi |
spellingShingle |
Lindbäck, Katrin Moholdt, Geir Nicholls, Keith W. Hattermann, Tore Pratap, Bhanu Thamban, Meloth Matsuoka, Kenichi Spatial and temporal variations in basal melting at Nivlisen ice shelf, East Antarctica, derived from phase-sensitive radars |
author_facet |
Lindbäck, Katrin Moholdt, Geir Nicholls, Keith W. Hattermann, Tore Pratap, Bhanu Thamban, Meloth Matsuoka, Kenichi |
author_sort |
Lindbäck, Katrin |
title |
Spatial and temporal variations in basal melting at Nivlisen ice shelf, East Antarctica, derived from phase-sensitive radars |
title_short |
Spatial and temporal variations in basal melting at Nivlisen ice shelf, East Antarctica, derived from phase-sensitive radars |
title_full |
Spatial and temporal variations in basal melting at Nivlisen ice shelf, East Antarctica, derived from phase-sensitive radars |
title_fullStr |
Spatial and temporal variations in basal melting at Nivlisen ice shelf, East Antarctica, derived from phase-sensitive radars |
title_full_unstemmed |
Spatial and temporal variations in basal melting at Nivlisen ice shelf, East Antarctica, derived from phase-sensitive radars |
title_sort |
spatial and temporal variations in basal melting at nivlisen ice shelf, east antarctica, derived from phase-sensitive radars |
publishDate |
2019 |
url |
https://doi.org/10.5194/tc-13-2579-2019 https://tc.copernicus.org/articles/13/2579/2019/ |
long_lat |
ENVELOPE(11.000,11.000,-70.333,-70.333) |
geographic |
Antarctic Dronning Maud Land East Antarctica Nivlisen |
geographic_facet |
Antarctic Dronning Maud Land East Antarctica Nivlisen |
genre |
Antarc* Antarctic Antarctica Dronning Maud Land East Antarctica Ice Shelf Ice Shelves Sea ice |
genre_facet |
Antarc* Antarctic Antarctica Dronning Maud Land East Antarctica Ice Shelf Ice Shelves Sea ice |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-13-2579-2019 https://tc.copernicus.org/articles/13/2579/2019/ |
op_doi |
https://doi.org/10.5194/tc-13-2579-2019 |
container_title |
The Cryosphere |
container_volume |
13 |
container_issue |
10 |
container_start_page |
2579 |
op_container_end_page |
2595 |
_version_ |
1766262108969762816 |