Dynamical modelling of Kara Sea land-fast ice
In this thesis land-fast ice is modelled based on the internal dynamics of sea ice. The region of interest is the Kara Sea, which has a well documented semi-permanent fast-ice cover. The Kara Sea fast ice is especially interesting because it forms over relatively deep waters compared to the maximum...
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Staats- und Universitätsbibliothek Hamburg Carl von Ossietzky
2012
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ftsubhamburg:oai:ediss.sub.uni-hamburg.de:ediss/4429 2023-05-15T16:59:50+02:00 Dynamical modelling of Kara Sea land-fast ice Dynamische Modellierung von Festeis in der Karasee Olason, Einar Örn Kaleschke, Lars (Jun. Prof. Dr.) 2012-01-01 http://nbn-resolving.de/urn:nbn:de:gbv:18-56105 https://ediss.sub.uni-hamburg.de/handle/ediss/4429 eng eng Staats- und Universitätsbibliothek Hamburg Carl von Ossietzky http://nbn-resolving.de/urn:nbn:de:gbv:18-56105 https://ediss.sub.uni-hamburg.de/handle/ediss/4429 http://purl.org/coar/access_right/c_abf2 info:eu-repo/semantics/openAccess No license Meereis Festeis Numerisches Modell Zirkulationsmodell Polynja sea ice land-fast ice numerical model general circulation model polynya 550 Geowissenschaften 38.90 Ozeanologie Ozeanographie Küstenmeer ddc:550 doctoralThesis doc-type:doctoralThesis 2012 ftsubhamburg 2022-11-09T07:10:47Z In this thesis land-fast ice is modelled based on the internal dynamics of sea ice. The region of interest is the Kara Sea, which has a well documented semi-permanent fast-ice cover. The Kara Sea fast ice is especially interesting because it forms over relatively deep waters compared to the maximum thickness of pressure ridges. This means that internal ice stresses must play an important role, in addition to the well-known grounding of pressure ridges. The main objective here is therefore to model the internal stresses of the ice well enough to reproduce the observed fast-ice cover. This has not been done successfully before. The model and methods developed here are general and should be applicable to other areas of fast-ice growth. In order to accurately model land-fast ice an improved version of the well-known viscous-plastic model is used. To produce a more physically realistic model material different yield curves are proposed while some numerical properties of the model are improved. The transition from plasticity to viscosity and the role of linear viscosity is also reconsidered. In an idealised stand-alone setup the model is used to investigate some general properties of polynya formation in the model. Coupling the ice model to an ocean model, realistic decadal simulations of the ice and ocean in the Kara Sea are then carried out testing some dynamic and thermodynamic properties of the model. Having thus confirmed that the model produces realistic results attempts are made to model land-fast ice. First the winter of 1997©-98 is considered in which various model parametrisations are tested and evaluated. Utilising the improved model and correct parametrisations the observed fast-ice cover can be reproduced during the height of the fast-ice season. After further tuning the fast-ice cover in 1967©-74 and 1997©-2005 could also be reproduced. The longer runs allow us to give an estimate of the minimum ice thickness required for fast ice to form over the deeper areas of the Kara Sea. Doctoral or Postdoctoral Thesis Kara Sea Sea ice ediss.sub.hamburg (Staats- und Universitätsbibliothek Hamburg, Carl von Ossietzky) Kara Sea |
institution |
Open Polar |
collection |
ediss.sub.hamburg (Staats- und Universitätsbibliothek Hamburg, Carl von Ossietzky) |
op_collection_id |
ftsubhamburg |
language |
English |
topic |
Meereis Festeis Numerisches Modell Zirkulationsmodell Polynja sea ice land-fast ice numerical model general circulation model polynya 550 Geowissenschaften 38.90 Ozeanologie Ozeanographie Küstenmeer ddc:550 |
spellingShingle |
Meereis Festeis Numerisches Modell Zirkulationsmodell Polynja sea ice land-fast ice numerical model general circulation model polynya 550 Geowissenschaften 38.90 Ozeanologie Ozeanographie Küstenmeer ddc:550 Olason, Einar Örn Dynamical modelling of Kara Sea land-fast ice |
topic_facet |
Meereis Festeis Numerisches Modell Zirkulationsmodell Polynja sea ice land-fast ice numerical model general circulation model polynya 550 Geowissenschaften 38.90 Ozeanologie Ozeanographie Küstenmeer ddc:550 |
description |
In this thesis land-fast ice is modelled based on the internal dynamics of sea ice. The region of interest is the Kara Sea, which has a well documented semi-permanent fast-ice cover. The Kara Sea fast ice is especially interesting because it forms over relatively deep waters compared to the maximum thickness of pressure ridges. This means that internal ice stresses must play an important role, in addition to the well-known grounding of pressure ridges. The main objective here is therefore to model the internal stresses of the ice well enough to reproduce the observed fast-ice cover. This has not been done successfully before. The model and methods developed here are general and should be applicable to other areas of fast-ice growth. In order to accurately model land-fast ice an improved version of the well-known viscous-plastic model is used. To produce a more physically realistic model material different yield curves are proposed while some numerical properties of the model are improved. The transition from plasticity to viscosity and the role of linear viscosity is also reconsidered. In an idealised stand-alone setup the model is used to investigate some general properties of polynya formation in the model. Coupling the ice model to an ocean model, realistic decadal simulations of the ice and ocean in the Kara Sea are then carried out testing some dynamic and thermodynamic properties of the model. Having thus confirmed that the model produces realistic results attempts are made to model land-fast ice. First the winter of 1997©-98 is considered in which various model parametrisations are tested and evaluated. Utilising the improved model and correct parametrisations the observed fast-ice cover can be reproduced during the height of the fast-ice season. After further tuning the fast-ice cover in 1967©-74 and 1997©-2005 could also be reproduced. The longer runs allow us to give an estimate of the minimum ice thickness required for fast ice to form over the deeper areas of the Kara Sea. |
author2 |
Kaleschke, Lars (Jun. Prof. Dr.) |
format |
Doctoral or Postdoctoral Thesis |
author |
Olason, Einar Örn |
author_facet |
Olason, Einar Örn |
author_sort |
Olason, Einar Örn |
title |
Dynamical modelling of Kara Sea land-fast ice |
title_short |
Dynamical modelling of Kara Sea land-fast ice |
title_full |
Dynamical modelling of Kara Sea land-fast ice |
title_fullStr |
Dynamical modelling of Kara Sea land-fast ice |
title_full_unstemmed |
Dynamical modelling of Kara Sea land-fast ice |
title_sort |
dynamical modelling of kara sea land-fast ice |
publisher |
Staats- und Universitätsbibliothek Hamburg Carl von Ossietzky |
publishDate |
2012 |
url |
http://nbn-resolving.de/urn:nbn:de:gbv:18-56105 https://ediss.sub.uni-hamburg.de/handle/ediss/4429 |
geographic |
Kara Sea |
geographic_facet |
Kara Sea |
genre |
Kara Sea Sea ice |
genre_facet |
Kara Sea Sea ice |
op_relation |
http://nbn-resolving.de/urn:nbn:de:gbv:18-56105 https://ediss.sub.uni-hamburg.de/handle/ediss/4429 |
op_rights |
http://purl.org/coar/access_right/c_abf2 info:eu-repo/semantics/openAccess No license |
_version_ |
1766052266384556032 |