The sea ice thickness in the Atlantic sector of the Southern Ocean
The remoteness of the Antarctic sea ice field and the fact that there is still no reliable way to measure its thickness from satellites renders it one of the most difficult geophysical parameters to measure. In this study, variations in sea ice thickness were examined by means of upward looking sona...
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Universität Bremen
2013
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Online Access: | https://media.suub.uni-bremen.de/handle/elib/532 https://nbn-resolving.org/urn:nbn:de:gbv:46-00103362-13 |
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ftsubbremen:oai:media.suub.uni-bremen.de:Publications/elib/532 2023-05-15T14:04:15+02:00 The sea ice thickness in the Atlantic sector of the Southern Ocean Die Meereisdicke im atlantischen Sektor des Südozeans Behrendt, Axel Lemke, Peter Fahrbach, Eberhard Kaleschke, Lars 2013-05-28 application/pdf https://media.suub.uni-bremen.de/handle/elib/532 https://nbn-resolving.org/urn:nbn:de:gbv:46-00103362-13 eng eng Universität Bremen FB1 Physik/Elektrotechnik https://media.suub.uni-bremen.de/handle/elib/532 urn:nbn:de:gbv:46-00103362-13 info:eu-repo/semantics/openAccess Bitte wählen Sie eine Lizenz aus: (Unsere Empfehlung: CC-BY) CC-BY sea ice sea ice thickness upward looking sonar Weddell Sea Antarctica oceanography climate 530 530 Physics ddc:530 Dissertation doctoralThesis 2013 ftsubbremen 2022-11-09T07:09:23Z The remoteness of the Antarctic sea ice field and the fact that there is still no reliable way to measure its thickness from satellites renders it one of the most difficult geophysical parameters to measure. In this study, variations in sea ice thickness were examined by means of upward looking sonar (ULS) measurements in the Weddell Sea. ULS instruments measure the subsurface portion (draft) of the ice as a proxy for sea ice thickness. Both quantities are linearly related. A consistent and extensive data set of sea ice draft was produced and its quality was investigated in detail. The obtained draft time series were studied in terms of variability, trends, oscillations and autocorrelation. A correlation analysis was performed to examine the geophysical driving mechanisms for changes in sea ice thickness and their relation to climate variability in the Southern Hemisphere. It was shown that sea ice draft can be measured with an accuracy of 5-12 cm, depending on the season. Furthermore, it was demonstrated that biases introduced by high ice concentration can be avoided by applying a simple sound speed model. Different significant oscillations with sub-annual periods and periods of up to 3-4 years were found in the draft time series. It was also shown that autocorrelation of sea ice thickness extends over up to eight years. Trends in the ice draft could be observed in three regions of the Weddell Sea: (1) A strong decline of about 2 m at the tip of the Antarctic Peninsula between the periods 1991-1992 and 2005-2007. (2) A statistically significant trend of -3 cm per year in the northeastern Weddell Sea during 2001-2005. (3) A statistically significant trend of 9 cm per year in the southeastern Weddell Sea during 2000-2004. The decrease in ice thickness in the peninsula region was found to be due to changing patterns of ice advection and is therefore not the result of temperature changes. The ice thickness, however, has become more sensitive to surface air temperature in the recent years. The trend in the ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Antarctic Peninsula Antarctica Sea ice Southern Ocean Weddell Sea Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) Antarctic Antarctic Peninsula Southern Ocean The Antarctic Weddell Weddell Sea |
institution |
Open Polar |
collection |
Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) |
op_collection_id |
ftsubbremen |
language |
English |
topic |
sea ice sea ice thickness upward looking sonar Weddell Sea Antarctica oceanography climate 530 530 Physics ddc:530 |
spellingShingle |
sea ice sea ice thickness upward looking sonar Weddell Sea Antarctica oceanography climate 530 530 Physics ddc:530 Behrendt, Axel The sea ice thickness in the Atlantic sector of the Southern Ocean |
topic_facet |
sea ice sea ice thickness upward looking sonar Weddell Sea Antarctica oceanography climate 530 530 Physics ddc:530 |
description |
The remoteness of the Antarctic sea ice field and the fact that there is still no reliable way to measure its thickness from satellites renders it one of the most difficult geophysical parameters to measure. In this study, variations in sea ice thickness were examined by means of upward looking sonar (ULS) measurements in the Weddell Sea. ULS instruments measure the subsurface portion (draft) of the ice as a proxy for sea ice thickness. Both quantities are linearly related. A consistent and extensive data set of sea ice draft was produced and its quality was investigated in detail. The obtained draft time series were studied in terms of variability, trends, oscillations and autocorrelation. A correlation analysis was performed to examine the geophysical driving mechanisms for changes in sea ice thickness and their relation to climate variability in the Southern Hemisphere. It was shown that sea ice draft can be measured with an accuracy of 5-12 cm, depending on the season. Furthermore, it was demonstrated that biases introduced by high ice concentration can be avoided by applying a simple sound speed model. Different significant oscillations with sub-annual periods and periods of up to 3-4 years were found in the draft time series. It was also shown that autocorrelation of sea ice thickness extends over up to eight years. Trends in the ice draft could be observed in three regions of the Weddell Sea: (1) A strong decline of about 2 m at the tip of the Antarctic Peninsula between the periods 1991-1992 and 2005-2007. (2) A statistically significant trend of -3 cm per year in the northeastern Weddell Sea during 2001-2005. (3) A statistically significant trend of 9 cm per year in the southeastern Weddell Sea during 2000-2004. The decrease in ice thickness in the peninsula region was found to be due to changing patterns of ice advection and is therefore not the result of temperature changes. The ice thickness, however, has become more sensitive to surface air temperature in the recent years. The trend in the ... |
author2 |
Lemke, Peter Fahrbach, Eberhard Kaleschke, Lars |
format |
Doctoral or Postdoctoral Thesis |
author |
Behrendt, Axel |
author_facet |
Behrendt, Axel |
author_sort |
Behrendt, Axel |
title |
The sea ice thickness in the Atlantic sector of the Southern Ocean |
title_short |
The sea ice thickness in the Atlantic sector of the Southern Ocean |
title_full |
The sea ice thickness in the Atlantic sector of the Southern Ocean |
title_fullStr |
The sea ice thickness in the Atlantic sector of the Southern Ocean |
title_full_unstemmed |
The sea ice thickness in the Atlantic sector of the Southern Ocean |
title_sort |
sea ice thickness in the atlantic sector of the southern ocean |
publisher |
Universität Bremen |
publishDate |
2013 |
url |
https://media.suub.uni-bremen.de/handle/elib/532 https://nbn-resolving.org/urn:nbn:de:gbv:46-00103362-13 |
geographic |
Antarctic Antarctic Peninsula Southern Ocean The Antarctic Weddell Weddell Sea |
geographic_facet |
Antarctic Antarctic Peninsula Southern Ocean The Antarctic Weddell Weddell Sea |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica Sea ice Southern Ocean Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica Sea ice Southern Ocean Weddell Sea |
op_relation |
https://media.suub.uni-bremen.de/handle/elib/532 urn:nbn:de:gbv:46-00103362-13 |
op_rights |
info:eu-repo/semantics/openAccess Bitte wählen Sie eine Lizenz aus: (Unsere Empfehlung: CC-BY) |
op_rightsnorm |
CC-BY |
_version_ |
1766275278490828800 |