Seasonal and interannual variability of landfast sea ice in Atka Bay, Weddell Sea, Antarctica
Landfast sea ice (fast ice) attached to Antarctic (near-)coastal elements is a critical component of the local physical and ecological systems. Through its direct coupling with the atmosphere and ocean, fast-ice properties are also a potential indicator of processes related to a changing climate. Ho...
Published in: | The Cryosphere |
---|---|
Main Authors: | , , , , |
Format: | Text |
Language: | English |
Published: |
2020
|
Subjects: | |
Online Access: | https://doi.org/10.5194/tc-14-2775-2020 https://tc.copernicus.org/articles/14/2775/2020/ |
id |
ftcopernicus:oai:publications.copernicus.org:tc81936 |
---|---|
record_format |
openpolar |
spelling |
ftcopernicus:oai:publications.copernicus.org:tc81936 2023-05-15T13:31:39+02:00 Seasonal and interannual variability of landfast sea ice in Atka Bay, Weddell Sea, Antarctica Arndt, Stefanie Hoppmann, Mario Schmithüsen, Holger Fraser, Alexander D. Nicolaus, Marcel 2020-08-31 application/pdf https://doi.org/10.5194/tc-14-2775-2020 https://tc.copernicus.org/articles/14/2775/2020/ eng eng doi:10.5194/tc-14-2775-2020 https://tc.copernicus.org/articles/14/2775/2020/ eISSN: 1994-0424 Text 2020 ftcopernicus https://doi.org/10.5194/tc-14-2775-2020 2020-09-07T16:22:14Z Landfast sea ice (fast ice) attached to Antarctic (near-)coastal elements is a critical component of the local physical and ecological systems. Through its direct coupling with the atmosphere and ocean, fast-ice properties are also a potential indicator of processes related to a changing climate. However, in situ fast-ice observations in Antarctica are extremely sparse because of logistical challenges and harsh environmental conditions. Since 2010, a monitoring program observing the seasonal evolution of fast ice in Atka Bay has been conducted as part of the Antarctic Fast Ice Network (AFIN). The bay is located on the northeastern edge of Ekström Ice Shelf in the eastern Weddell Sea, close to the German wintering station Neumayer III. A number of sampling sites have been regularly revisited each year between annual ice formation and breakup to obtain a continuous record of sea-ice and sub-ice platelet-layer thickness, as well as snow depth and freeboard across the bay. Here, we present the time series of these measurements over the last 9 years. Combining them with observations from the nearby Neumayer III meteorological observatory as well as auxiliary satellite images enables us to relate the seasonal and interannual fast-ice cycle to the factors that influence their evolution. On average, the annual consolidated fast-ice thickness at the end of the growth season is about 2 m, with a loose platelet layer of 4 m thickness beneath and 0.70 m thick snow on top. Results highlight the predominately seasonal character of the fast-ice regime in Atka Bay without a significant interannual trend in any of the observed variables over the 9-year observation period. Also, no changes are evident when comparing with sporadic measurements in the 1980s and 1990s. It is shown that strong easterly winds in the area govern the year-round snow distribution and also trigger the breakup of fast ice in the bay during summer months. Due to the substantial snow accumulation on the fast ice, a characteristic feature is frequent negative freeboard, associated flooding of the snow–ice interface, and a likely subsequent snow ice formation. The buoyant platelet layer beneath negates the snow weight to some extent, but snow thermodynamics is identified as the main driver of the energy and mass budgets for the fast-ice cover in Atka Bay. The new knowledge of the seasonal and interannual variability of fast-ice properties from the present study helps to improve our understanding of interactions between atmosphere, fast ice, ocean, and ice shelves in one of the key regions of Antarctica and calls for intensified multidisciplinary studies in this region. Text Antarc* Antarctic Antarctica Ice Shelf Ice Shelves Sea ice Weddell Sea Copernicus Publications: E-Journals Antarctic Atka ENVELOPE(151.789,151.789,60.835,60.835) Ekström Ice Shelf ENVELOPE(-8.000,-8.000,-71.000,-71.000) Neumayer The Antarctic Weddell Weddell Sea The Cryosphere 14 9 2775 2793 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Landfast sea ice (fast ice) attached to Antarctic (near-)coastal elements is a critical component of the local physical and ecological systems. Through its direct coupling with the atmosphere and ocean, fast-ice properties are also a potential indicator of processes related to a changing climate. However, in situ fast-ice observations in Antarctica are extremely sparse because of logistical challenges and harsh environmental conditions. Since 2010, a monitoring program observing the seasonal evolution of fast ice in Atka Bay has been conducted as part of the Antarctic Fast Ice Network (AFIN). The bay is located on the northeastern edge of Ekström Ice Shelf in the eastern Weddell Sea, close to the German wintering station Neumayer III. A number of sampling sites have been regularly revisited each year between annual ice formation and breakup to obtain a continuous record of sea-ice and sub-ice platelet-layer thickness, as well as snow depth and freeboard across the bay. Here, we present the time series of these measurements over the last 9 years. Combining them with observations from the nearby Neumayer III meteorological observatory as well as auxiliary satellite images enables us to relate the seasonal and interannual fast-ice cycle to the factors that influence their evolution. On average, the annual consolidated fast-ice thickness at the end of the growth season is about 2 m, with a loose platelet layer of 4 m thickness beneath and 0.70 m thick snow on top. Results highlight the predominately seasonal character of the fast-ice regime in Atka Bay without a significant interannual trend in any of the observed variables over the 9-year observation period. Also, no changes are evident when comparing with sporadic measurements in the 1980s and 1990s. It is shown that strong easterly winds in the area govern the year-round snow distribution and also trigger the breakup of fast ice in the bay during summer months. Due to the substantial snow accumulation on the fast ice, a characteristic feature is frequent negative freeboard, associated flooding of the snow–ice interface, and a likely subsequent snow ice formation. The buoyant platelet layer beneath negates the snow weight to some extent, but snow thermodynamics is identified as the main driver of the energy and mass budgets for the fast-ice cover in Atka Bay. The new knowledge of the seasonal and interannual variability of fast-ice properties from the present study helps to improve our understanding of interactions between atmosphere, fast ice, ocean, and ice shelves in one of the key regions of Antarctica and calls for intensified multidisciplinary studies in this region. |
format |
Text |
author |
Arndt, Stefanie Hoppmann, Mario Schmithüsen, Holger Fraser, Alexander D. Nicolaus, Marcel |
spellingShingle |
Arndt, Stefanie Hoppmann, Mario Schmithüsen, Holger Fraser, Alexander D. Nicolaus, Marcel Seasonal and interannual variability of landfast sea ice in Atka Bay, Weddell Sea, Antarctica |
author_facet |
Arndt, Stefanie Hoppmann, Mario Schmithüsen, Holger Fraser, Alexander D. Nicolaus, Marcel |
author_sort |
Arndt, Stefanie |
title |
Seasonal and interannual variability of landfast sea ice in Atka Bay, Weddell Sea, Antarctica |
title_short |
Seasonal and interannual variability of landfast sea ice in Atka Bay, Weddell Sea, Antarctica |
title_full |
Seasonal and interannual variability of landfast sea ice in Atka Bay, Weddell Sea, Antarctica |
title_fullStr |
Seasonal and interannual variability of landfast sea ice in Atka Bay, Weddell Sea, Antarctica |
title_full_unstemmed |
Seasonal and interannual variability of landfast sea ice in Atka Bay, Weddell Sea, Antarctica |
title_sort |
seasonal and interannual variability of landfast sea ice in atka bay, weddell sea, antarctica |
publishDate |
2020 |
url |
https://doi.org/10.5194/tc-14-2775-2020 https://tc.copernicus.org/articles/14/2775/2020/ |
long_lat |
ENVELOPE(151.789,151.789,60.835,60.835) ENVELOPE(-8.000,-8.000,-71.000,-71.000) |
geographic |
Antarctic Atka Ekström Ice Shelf Neumayer The Antarctic Weddell Weddell Sea |
geographic_facet |
Antarctic Atka Ekström Ice Shelf Neumayer The Antarctic Weddell Weddell Sea |
genre |
Antarc* Antarctic Antarctica Ice Shelf Ice Shelves Sea ice Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctica Ice Shelf Ice Shelves Sea ice Weddell Sea |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-14-2775-2020 https://tc.copernicus.org/articles/14/2775/2020/ |
op_doi |
https://doi.org/10.5194/tc-14-2775-2020 |
container_title |
The Cryosphere |
container_volume |
14 |
container_issue |
9 |
container_start_page |
2775 |
op_container_end_page |
2793 |
_version_ |
1766019692493799424 |