Resolving Leads in Sea-Ice Models : New Analysis Methods for Frontier Resolution Arctic Simulations
Sea ice deforms constantly under the forcing of winds and ocean currents. Eventually the ice cover of the Arctic Ocean breaks into a multitude of ice floes. Strips of open ocean, so-called leads, and pressure ridges, where the collision of floes piled up the ice, are found along the floe boundaries....
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Universität Bremen
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ftsubbremen:oai:media.suub.uni-bremen.de:Publications/elib/1711 2023-05-15T14:52:25+02:00 Resolving Leads in Sea-Ice Models : New Analysis Methods for Frontier Resolution Arctic Simulations Modellieren von Meereisrinnen : Neue Analysemethoden für Arktische Simulationen mit extremen Auflösungen Hutter, Nils Jung, Thomas Haas, Christian 2019-08-15 application/pdf https://media.suub.uni-bremen.de/handle/elib/1711 https://nbn-resolving.org/urn:nbn:de:gbv:46-00107794-12 eng eng Universität Bremen FB1 Physik/Elektrotechnik https://media.suub.uni-bremen.de/handle/elib/1711 urn:nbn:de:gbv:46-00107794-12 info:eu-repo/semantics/openAccess Arctic sea ice sea-ice modelling high-resolution remote sensing sea-ice observations MITgcm LKFs leads pressure-ridges Linear Kinematic Features lead-resolving sea-ice simulation scaling power-law scaling analysis fractal multi-fractal image detection lead detection automated detection evaluation validation 530 530 Physics ddc:530 Dissertation doctoralThesis 2019 ftsubbremen 2022-11-09T07:09:39Z Sea ice deforms constantly under the forcing of winds and ocean currents. Eventually the ice cover of the Arctic Ocean breaks into a multitude of ice floes. Strips of open ocean, so-called leads, and pressure ridges, where the collision of floes piled up the ice, are found along the floe boundaries. These features have a strong impact on the interaction of sea ice with the atmosphere and the ocean, as they affect heat loss and surface drag. Currently, climate models do not resolve leads and pressure ridges in simulated sea ice fields due to their coarse resolution. They parameterize the effects of leads on the Arctic climate, if at all. The goal of this thesis is to develop Arctic simulations that reproduce leads sufficiently to be used in climate simulations. By decreasing the horizontal grid-spacing, a numerical ocean sea-ice model is shown to resolve leads explicitly. To test how realistic these lead-resolving sea-ice simulations are, the following research questions are addressed: (1) what are good metrics to evaluate the simulated leads with observational data? (2) Which observed characteristics of sea ice deformation and deformation features are reproduced by the model? In a first step, the sea ice deformation in a 1-km lead-resolving sea-ice simulation is analyzed with a spatio-temporal scaling analysis. The simulated sea ice deformation is strongly localized in failure zones and dominated by spontaneous fracture. This heterogeneity and intermittency of sea ice deformation shows that the simulation captures the fracture processes that form leads. In a second step, two new algorithms are described that detect and track leads and pressure ridges, combined into Linear Kinematic Features (LKFs). Both algorithms are applied to deformation data observed from satellite to establish a data set of deformation features that can be used as a reference in model evaluation. LKFs in two lead-resolving sea-ice simulations are extracted with the same algorithms, and found to agree with the LKF data set with respect to ... Doctoral or Postdoctoral Thesis Arctic Arctic Ocean Arktis* Sea ice Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) Arctic Arctic Ocean |
institution |
Open Polar |
collection |
Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) |
op_collection_id |
ftsubbremen |
language |
English |
topic |
Arctic sea ice sea-ice modelling high-resolution remote sensing sea-ice observations MITgcm LKFs leads pressure-ridges Linear Kinematic Features lead-resolving sea-ice simulation scaling power-law scaling analysis fractal multi-fractal image detection lead detection automated detection evaluation validation 530 530 Physics ddc:530 |
spellingShingle |
Arctic sea ice sea-ice modelling high-resolution remote sensing sea-ice observations MITgcm LKFs leads pressure-ridges Linear Kinematic Features lead-resolving sea-ice simulation scaling power-law scaling analysis fractal multi-fractal image detection lead detection automated detection evaluation validation 530 530 Physics ddc:530 Hutter, Nils Resolving Leads in Sea-Ice Models : New Analysis Methods for Frontier Resolution Arctic Simulations |
topic_facet |
Arctic sea ice sea-ice modelling high-resolution remote sensing sea-ice observations MITgcm LKFs leads pressure-ridges Linear Kinematic Features lead-resolving sea-ice simulation scaling power-law scaling analysis fractal multi-fractal image detection lead detection automated detection evaluation validation 530 530 Physics ddc:530 |
description |
Sea ice deforms constantly under the forcing of winds and ocean currents. Eventually the ice cover of the Arctic Ocean breaks into a multitude of ice floes. Strips of open ocean, so-called leads, and pressure ridges, where the collision of floes piled up the ice, are found along the floe boundaries. These features have a strong impact on the interaction of sea ice with the atmosphere and the ocean, as they affect heat loss and surface drag. Currently, climate models do not resolve leads and pressure ridges in simulated sea ice fields due to their coarse resolution. They parameterize the effects of leads on the Arctic climate, if at all. The goal of this thesis is to develop Arctic simulations that reproduce leads sufficiently to be used in climate simulations. By decreasing the horizontal grid-spacing, a numerical ocean sea-ice model is shown to resolve leads explicitly. To test how realistic these lead-resolving sea-ice simulations are, the following research questions are addressed: (1) what are good metrics to evaluate the simulated leads with observational data? (2) Which observed characteristics of sea ice deformation and deformation features are reproduced by the model? In a first step, the sea ice deformation in a 1-km lead-resolving sea-ice simulation is analyzed with a spatio-temporal scaling analysis. The simulated sea ice deformation is strongly localized in failure zones and dominated by spontaneous fracture. This heterogeneity and intermittency of sea ice deformation shows that the simulation captures the fracture processes that form leads. In a second step, two new algorithms are described that detect and track leads and pressure ridges, combined into Linear Kinematic Features (LKFs). Both algorithms are applied to deformation data observed from satellite to establish a data set of deformation features that can be used as a reference in model evaluation. LKFs in two lead-resolving sea-ice simulations are extracted with the same algorithms, and found to agree with the LKF data set with respect to ... |
author2 |
Jung, Thomas Haas, Christian |
format |
Doctoral or Postdoctoral Thesis |
author |
Hutter, Nils |
author_facet |
Hutter, Nils |
author_sort |
Hutter, Nils |
title |
Resolving Leads in Sea-Ice Models : New Analysis Methods for Frontier Resolution Arctic Simulations |
title_short |
Resolving Leads in Sea-Ice Models : New Analysis Methods for Frontier Resolution Arctic Simulations |
title_full |
Resolving Leads in Sea-Ice Models : New Analysis Methods for Frontier Resolution Arctic Simulations |
title_fullStr |
Resolving Leads in Sea-Ice Models : New Analysis Methods for Frontier Resolution Arctic Simulations |
title_full_unstemmed |
Resolving Leads in Sea-Ice Models : New Analysis Methods for Frontier Resolution Arctic Simulations |
title_sort |
resolving leads in sea-ice models : new analysis methods for frontier resolution arctic simulations |
publisher |
Universität Bremen |
publishDate |
2019 |
url |
https://media.suub.uni-bremen.de/handle/elib/1711 https://nbn-resolving.org/urn:nbn:de:gbv:46-00107794-12 |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Arktis* Sea ice |
genre_facet |
Arctic Arctic Ocean Arktis* Sea ice |
op_relation |
https://media.suub.uni-bremen.de/handle/elib/1711 urn:nbn:de:gbv:46-00107794-12 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766323664191488000 |