Numerical Modeling Of Seasonally Freezing Ground And Permafrost
Dissertation (Ph.D.) University of Alaska Fairbanks, 2007 This thesis represents a collection of papers on numerical modeling of permafrost and seasonally freezing ground dynamics. An important problem in numerical modeling of temperature dynamics in permafrost and seasonally freezing ground is rela...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/8940 2023-05-15T15:46:59+02:00 Numerical Modeling Of Seasonally Freezing Ground And Permafrost Nicolsky, Dmitry J. Romanovsky, Vladimir 2007 http://hdl.handle.net/11122/8940 unknown http://hdl.handle.net/11122/8940 Department of Geology and Geophysics Geophysics Dissertation phd 2007 ftunivalaska 2023-02-23T21:37:09Z Dissertation (Ph.D.) University of Alaska Fairbanks, 2007 This thesis represents a collection of papers on numerical modeling of permafrost and seasonally freezing ground dynamics. An important problem in numerical modeling of temperature dynamics in permafrost and seasonally freezing ground is related to parametrization of already existing models. In this thesis, a variation data assimilation technique is presented to find soil properties by minimizing the discrepancy between in-situ measured temperatures and those computed by the models. The iterative minimization starts from an initial approximation of the soil properties that are found by solving a sequence of simple subproblems. In order to compute the discrepancy, the temperature dynamics is simulated by a new implementation of the finite element method applied to the heat equation with phase change. Despite simplifications in soil physics, the presented technique was successfully applied to recover soil properties, such as thermal conductivity, soil porosity, and the unfrozen water content, at several sites in Alaska. The recovered properties are used in discussion on soil freezing/thawing and permafrost dynamics in other parts of this thesis. Another part of this thesis concerns development of a numerical thermo-mechanical model of seasonal soil freezing on the lateral scale of several meters. The presented model explains observed differential frost heave occurring in non-sorted circle ecosystems north of the Brooks Range in the Alaskan tundra. The model takes into account conservation principles for energy, linear momentum and mass of three constituents: liquid water, ice and solid particles. The conservation principles are reduced to a computationally convenient system of coupled equations for temperature, liquid water pressure, porosity, and the velocity of soil particles in a three-dimensional domain with cylindrical symmetry. Despite a simplified rheology, the model simulates the ground surface motion, temperature, and water dynamics in soil and ... Doctoral or Postdoctoral Thesis Brooks Range Ice permafrost Tundra Alaska University of Alaska: ScholarWorks@UA Fairbanks |
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University of Alaska: ScholarWorks@UA |
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ftunivalaska |
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unknown |
topic |
Geophysics |
spellingShingle |
Geophysics Nicolsky, Dmitry J. Numerical Modeling Of Seasonally Freezing Ground And Permafrost |
topic_facet |
Geophysics |
description |
Dissertation (Ph.D.) University of Alaska Fairbanks, 2007 This thesis represents a collection of papers on numerical modeling of permafrost and seasonally freezing ground dynamics. An important problem in numerical modeling of temperature dynamics in permafrost and seasonally freezing ground is related to parametrization of already existing models. In this thesis, a variation data assimilation technique is presented to find soil properties by minimizing the discrepancy between in-situ measured temperatures and those computed by the models. The iterative minimization starts from an initial approximation of the soil properties that are found by solving a sequence of simple subproblems. In order to compute the discrepancy, the temperature dynamics is simulated by a new implementation of the finite element method applied to the heat equation with phase change. Despite simplifications in soil physics, the presented technique was successfully applied to recover soil properties, such as thermal conductivity, soil porosity, and the unfrozen water content, at several sites in Alaska. The recovered properties are used in discussion on soil freezing/thawing and permafrost dynamics in other parts of this thesis. Another part of this thesis concerns development of a numerical thermo-mechanical model of seasonal soil freezing on the lateral scale of several meters. The presented model explains observed differential frost heave occurring in non-sorted circle ecosystems north of the Brooks Range in the Alaskan tundra. The model takes into account conservation principles for energy, linear momentum and mass of three constituents: liquid water, ice and solid particles. The conservation principles are reduced to a computationally convenient system of coupled equations for temperature, liquid water pressure, porosity, and the velocity of soil particles in a three-dimensional domain with cylindrical symmetry. Despite a simplified rheology, the model simulates the ground surface motion, temperature, and water dynamics in soil and ... |
author2 |
Romanovsky, Vladimir |
format |
Doctoral or Postdoctoral Thesis |
author |
Nicolsky, Dmitry J. |
author_facet |
Nicolsky, Dmitry J. |
author_sort |
Nicolsky, Dmitry J. |
title |
Numerical Modeling Of Seasonally Freezing Ground And Permafrost |
title_short |
Numerical Modeling Of Seasonally Freezing Ground And Permafrost |
title_full |
Numerical Modeling Of Seasonally Freezing Ground And Permafrost |
title_fullStr |
Numerical Modeling Of Seasonally Freezing Ground And Permafrost |
title_full_unstemmed |
Numerical Modeling Of Seasonally Freezing Ground And Permafrost |
title_sort |
numerical modeling of seasonally freezing ground and permafrost |
publishDate |
2007 |
url |
http://hdl.handle.net/11122/8940 |
geographic |
Fairbanks |
geographic_facet |
Fairbanks |
genre |
Brooks Range Ice permafrost Tundra Alaska |
genre_facet |
Brooks Range Ice permafrost Tundra Alaska |
op_relation |
http://hdl.handle.net/11122/8940 Department of Geology and Geophysics |
_version_ |
1766381800227078144 |