Modelling heat transfer in permafrost with COMSOL

Thawing of permafrost is widely observed, and its rate is expected to be accelerated due to the global warming caused by anthropogenic climate change. Although permafrost thawing has been acknowledged in IPCC Assessment reports, uncertainties related to model-based estimates of its extent and magnit...

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Main Author: Korhonen, Vesa
Other Authors: Helsingin yliopisto, Matemaattis-luonnontieteellinen tiedekunta, University of Helsinki, Faculty of Science, Helsingfors universitet, Matematisk-naturvetenskapliga fakulteten
Format: Master Thesis
Language:English
Published: Helsingin yliopisto 2023
Subjects:
Online Access:http://hdl.handle.net/10138/564303
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spelling ftunivhelsihelda:oai:helda.helsinki.fi:10138/564303 2023-10-09T21:55:07+02:00 Modelling heat transfer in permafrost with COMSOL Korhonen, Vesa Helsingin yliopisto, Matemaattis-luonnontieteellinen tiedekunta University of Helsinki, Faculty of Science Helsingfors universitet, Matematisk-naturvetenskapliga fakulteten 2023 application/pdf http://hdl.handle.net/10138/564303 eng eng Helsingin yliopisto University of Helsinki Helsingfors universitet URN:NBN:fi:hulib-202308223563 http://hdl.handle.net/10138/564303 Heat transfer modelling Permafrost modelling COMSOL Nadym Ilmakehätieteiden maisteriohjelma (Atmospheric Sciences) Master's Programme in Atmospheric Sciences Magisterprogrammet i atmosfärsvetenskaper Hydrosfäärin geofysiikka Geophysics of the Hydrosphere Hydrosfärens geofysik pro gradu -tutkielmat master's thesis pro gradu-avhandlingar 2023 ftunivhelsihelda 2023-09-13T23:01:04Z Thawing of permafrost is widely observed, and its rate is expected to be accelerated due to the global warming caused by anthropogenic climate change. Although permafrost thawing has been acknowledged in IPCC Assessment reports, uncertainties related to model-based estimates of its extent and magnitude in the future exist due to the challenges for the models to account for heterogeneous changes in permafrost under the changing climate. Various one-dimensional finite element conductive heat transfer model codes have been successfully used for simulating permafrost, while models created with the COMSOL multiphysics tool have seen little use. In this work, COMSOL version 5.6 was chosen for modelling the heat transfer in permafrost. COMSOLs' ability to accurately simulate thermal evolution in porous medium experiencing freezing was demonstrated using the Interfrost test case T1, which is a benchmark modelling problem adapted to use by the Intercomparison project for TH (Thermo-Hydro) coupled heat and water transfers in permafrost regions. Benchmark results agreed with Lunardini's analytical solution, although compared to the previous studies, the results had more deviation from the analytical solution. Discontinuous permafrost in North-Western Siberia is thawing. Based on the temperature measurements available from three boreholes located in the area (Nadym), and an observed increasing mean annual air temperature trend of 0.5\textdegree C per decade, the rate of thawing could be increasing. A one-dimensional heat transfer model for one of the boreholes was created and benchmarked against soil temperature measurements to form a basis for future estimates of the permafrost evolution. The temperature time series produced by the model agreed moderately with the measurements, but the need for further model improvements was identified. Adjustments proposed in this work and parameter changes indicated by the sensitivity analysis form a basis for further model development. Additionally, the results of the conducted ... Master Thesis permafrost Siberia Helsingfors Universitet: HELDA – Helsingin yliopiston digitaalinen arkisto Nadym ENVELOPE(72.517,72.517,65.533,65.533)
institution Open Polar
collection Helsingfors Universitet: HELDA – Helsingin yliopiston digitaalinen arkisto
op_collection_id ftunivhelsihelda
language English
topic Heat transfer modelling
Permafrost modelling
COMSOL
Nadym
Ilmakehätieteiden maisteriohjelma (Atmospheric Sciences)
Master's Programme in Atmospheric Sciences
Magisterprogrammet i atmosfärsvetenskaper
Hydrosfäärin geofysiikka
Geophysics of the Hydrosphere
Hydrosfärens geofysik
spellingShingle Heat transfer modelling
Permafrost modelling
COMSOL
Nadym
Ilmakehätieteiden maisteriohjelma (Atmospheric Sciences)
Master's Programme in Atmospheric Sciences
Magisterprogrammet i atmosfärsvetenskaper
Hydrosfäärin geofysiikka
Geophysics of the Hydrosphere
Hydrosfärens geofysik
Korhonen, Vesa
Modelling heat transfer in permafrost with COMSOL
topic_facet Heat transfer modelling
Permafrost modelling
COMSOL
Nadym
Ilmakehätieteiden maisteriohjelma (Atmospheric Sciences)
Master's Programme in Atmospheric Sciences
Magisterprogrammet i atmosfärsvetenskaper
Hydrosfäärin geofysiikka
Geophysics of the Hydrosphere
Hydrosfärens geofysik
description Thawing of permafrost is widely observed, and its rate is expected to be accelerated due to the global warming caused by anthropogenic climate change. Although permafrost thawing has been acknowledged in IPCC Assessment reports, uncertainties related to model-based estimates of its extent and magnitude in the future exist due to the challenges for the models to account for heterogeneous changes in permafrost under the changing climate. Various one-dimensional finite element conductive heat transfer model codes have been successfully used for simulating permafrost, while models created with the COMSOL multiphysics tool have seen little use. In this work, COMSOL version 5.6 was chosen for modelling the heat transfer in permafrost. COMSOLs' ability to accurately simulate thermal evolution in porous medium experiencing freezing was demonstrated using the Interfrost test case T1, which is a benchmark modelling problem adapted to use by the Intercomparison project for TH (Thermo-Hydro) coupled heat and water transfers in permafrost regions. Benchmark results agreed with Lunardini's analytical solution, although compared to the previous studies, the results had more deviation from the analytical solution. Discontinuous permafrost in North-Western Siberia is thawing. Based on the temperature measurements available from three boreholes located in the area (Nadym), and an observed increasing mean annual air temperature trend of 0.5\textdegree C per decade, the rate of thawing could be increasing. A one-dimensional heat transfer model for one of the boreholes was created and benchmarked against soil temperature measurements to form a basis for future estimates of the permafrost evolution. The temperature time series produced by the model agreed moderately with the measurements, but the need for further model improvements was identified. Adjustments proposed in this work and parameter changes indicated by the sensitivity analysis form a basis for further model development. Additionally, the results of the conducted ...
author2 Helsingin yliopisto, Matemaattis-luonnontieteellinen tiedekunta
University of Helsinki, Faculty of Science
Helsingfors universitet, Matematisk-naturvetenskapliga fakulteten
format Master Thesis
author Korhonen, Vesa
author_facet Korhonen, Vesa
author_sort Korhonen, Vesa
title Modelling heat transfer in permafrost with COMSOL
title_short Modelling heat transfer in permafrost with COMSOL
title_full Modelling heat transfer in permafrost with COMSOL
title_fullStr Modelling heat transfer in permafrost with COMSOL
title_full_unstemmed Modelling heat transfer in permafrost with COMSOL
title_sort modelling heat transfer in permafrost with comsol
publisher Helsingin yliopisto
publishDate 2023
url http://hdl.handle.net/10138/564303
long_lat ENVELOPE(72.517,72.517,65.533,65.533)
geographic Nadym
geographic_facet Nadym
genre permafrost
Siberia
genre_facet permafrost
Siberia
op_relation URN:NBN:fi:hulib-202308223563
http://hdl.handle.net/10138/564303
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