Internal dynamics of a medium-sized subarctic lake: field measurements and numerical modeling
As the Arctic Circle opens up due to the effects of global warming, the surrounding regions, and in particular the subarctic zone, experience both climatic and societal changes, which makes it imperative to understand the existing ecosystems. Lake Lagarfljót, an Icelandic fjord lake with glacial inf...
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Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
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University of Iceland, School of Engineering and Natural Sciences, Faculty of Civil and Environmental Engineering
2019
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Online Access: | https://hdl.handle.net/20.500.11815/1273 |
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ftopinvisindi:oai:opinvisindi.is:20.500.11815/1273 2023-05-15T15:03:35+02:00 Internal dynamics of a medium-sized subarctic lake: field measurements and numerical modeling Priet-Mahéo, Morgane Hrund Ólöf Andradóttir Umhverfis- og byggingarverkfræðideild (HÍ) Faculty of Civil and Environmental Engineering (UI) Verkfræði- og náttúruvísindasvið (HÍ) School of Engineering and Natural Sciences (UI) Háskóli Íslands University of Iceland 2019-09 145 https://hdl.handle.net/20.500.11815/1273 en eng University of Iceland, School of Engineering and Natural Sciences, Faculty of Civil and Environmental Engineering Morgane Priet-Mahéo, 2019, Internal dynamics of a medium-sized subarctic lake: field measurements and numerical modeling, PhD dissertation, Faculty of Civil and Environmental Engineering, University of Iceland, 145 pp. 978-9935-9473-6-9 https://hdl.handle.net/20.500.11815/1273 info:eu-repo/semantics/openAccess Limnology Hydrodynamics Inflow Numerical model Subarctic Cimate change Lagarfljót Vatnalíffræði Straumfræði Reiknilíkön Norður-heimskautið Hlýnun jarðar Loftslagsbreytingar Umhverfisfræði Doktorsritgerðir info:eu-repo/semantics/doctoralThesis 2019 ftopinvisindi https://doi.org/20.500.11815/1273 2022-11-18T06:51:46Z As the Arctic Circle opens up due to the effects of global warming, the surrounding regions, and in particular the subarctic zone, experience both climatic and societal changes, which makes it imperative to understand the existing ecosystems. Lake Lagarfljót, an Icelandic fjord lake with glacial inflow, is used to evaluate processes occurring in weakly stratified water bodies in the sub-Arctic. Field observations during the summers of 2010 and 2011 show that the lake experiences a short period of stratification, with overturning occurring when the heat fluxes become negative. The internal-wave regime evolves rapidly as the stratification strengthens, higher vertical modes and Kelvin waves are identified. Glacial inflow to Lake Lagarfljót delivers large volumes of fine sediment. It is expected that most of the sediments remain in suspension and this can alter the density of the water-column, resulting in inverse thermal gradients. Additionally, the glacial river is deflected to the eastern edge of the lake by Coriolis forces, causing the inflow to remain in shallow water before entering the center of the lake. Results from the Münnich model demonstrate that the natural oscillation of the lake basin is close to the oscillation period of the wind. The 3D hydrodynamic model Si3D was adapted to account for suspended sediment, and it successfully reproduced the motions observed in the lake, showing its utility for the study of weakly stratified lakes. Results suggest that wind is the main driver of internal waves in Lake Lagarfljót, but that the river influences stratification, meaning that it cannot be ignored when considering lake circulation. The model confirms the presence of Kelvin waves in the basin. Tracking the pathways of the inflowing glacial water, it appears that the initial intrusion depth is dependent on internal waves. During summertime stratification, the river penetrates the lake as interflows or underflows. Underflows can become trapped, causing them to oscillate and becoming flushed episodically ... Doctoral or Postdoctoral Thesis Arctic Global warming Lagarfljót Subarctic Opin vísindi (Iceland) Arctic Lagarfljót ENVELOPE(-14.600,-14.600,65.183,65.183) |
institution |
Open Polar |
collection |
Opin vísindi (Iceland) |
op_collection_id |
ftopinvisindi |
language |
English |
topic |
Limnology Hydrodynamics Inflow Numerical model Subarctic Cimate change Lagarfljót Vatnalíffræði Straumfræði Reiknilíkön Norður-heimskautið Hlýnun jarðar Loftslagsbreytingar Umhverfisfræði Doktorsritgerðir |
spellingShingle |
Limnology Hydrodynamics Inflow Numerical model Subarctic Cimate change Lagarfljót Vatnalíffræði Straumfræði Reiknilíkön Norður-heimskautið Hlýnun jarðar Loftslagsbreytingar Umhverfisfræði Doktorsritgerðir Priet-Mahéo, Morgane Internal dynamics of a medium-sized subarctic lake: field measurements and numerical modeling |
topic_facet |
Limnology Hydrodynamics Inflow Numerical model Subarctic Cimate change Lagarfljót Vatnalíffræði Straumfræði Reiknilíkön Norður-heimskautið Hlýnun jarðar Loftslagsbreytingar Umhverfisfræði Doktorsritgerðir |
description |
As the Arctic Circle opens up due to the effects of global warming, the surrounding regions, and in particular the subarctic zone, experience both climatic and societal changes, which makes it imperative to understand the existing ecosystems. Lake Lagarfljót, an Icelandic fjord lake with glacial inflow, is used to evaluate processes occurring in weakly stratified water bodies in the sub-Arctic. Field observations during the summers of 2010 and 2011 show that the lake experiences a short period of stratification, with overturning occurring when the heat fluxes become negative. The internal-wave regime evolves rapidly as the stratification strengthens, higher vertical modes and Kelvin waves are identified. Glacial inflow to Lake Lagarfljót delivers large volumes of fine sediment. It is expected that most of the sediments remain in suspension and this can alter the density of the water-column, resulting in inverse thermal gradients. Additionally, the glacial river is deflected to the eastern edge of the lake by Coriolis forces, causing the inflow to remain in shallow water before entering the center of the lake. Results from the Münnich model demonstrate that the natural oscillation of the lake basin is close to the oscillation period of the wind. The 3D hydrodynamic model Si3D was adapted to account for suspended sediment, and it successfully reproduced the motions observed in the lake, showing its utility for the study of weakly stratified lakes. Results suggest that wind is the main driver of internal waves in Lake Lagarfljót, but that the river influences stratification, meaning that it cannot be ignored when considering lake circulation. The model confirms the presence of Kelvin waves in the basin. Tracking the pathways of the inflowing glacial water, it appears that the initial intrusion depth is dependent on internal waves. During summertime stratification, the river penetrates the lake as interflows or underflows. Underflows can become trapped, causing them to oscillate and becoming flushed episodically ... |
author2 |
Hrund Ólöf Andradóttir Umhverfis- og byggingarverkfræðideild (HÍ) Faculty of Civil and Environmental Engineering (UI) Verkfræði- og náttúruvísindasvið (HÍ) School of Engineering and Natural Sciences (UI) Háskóli Íslands University of Iceland |
format |
Doctoral or Postdoctoral Thesis |
author |
Priet-Mahéo, Morgane |
author_facet |
Priet-Mahéo, Morgane |
author_sort |
Priet-Mahéo, Morgane |
title |
Internal dynamics of a medium-sized subarctic lake: field measurements and numerical modeling |
title_short |
Internal dynamics of a medium-sized subarctic lake: field measurements and numerical modeling |
title_full |
Internal dynamics of a medium-sized subarctic lake: field measurements and numerical modeling |
title_fullStr |
Internal dynamics of a medium-sized subarctic lake: field measurements and numerical modeling |
title_full_unstemmed |
Internal dynamics of a medium-sized subarctic lake: field measurements and numerical modeling |
title_sort |
internal dynamics of a medium-sized subarctic lake: field measurements and numerical modeling |
publisher |
University of Iceland, School of Engineering and Natural Sciences, Faculty of Civil and Environmental Engineering |
publishDate |
2019 |
url |
https://hdl.handle.net/20.500.11815/1273 |
long_lat |
ENVELOPE(-14.600,-14.600,65.183,65.183) |
geographic |
Arctic Lagarfljót |
geographic_facet |
Arctic Lagarfljót |
genre |
Arctic Global warming Lagarfljót Subarctic |
genre_facet |
Arctic Global warming Lagarfljót Subarctic |
op_relation |
Morgane Priet-Mahéo, 2019, Internal dynamics of a medium-sized subarctic lake: field measurements and numerical modeling, PhD dissertation, Faculty of Civil and Environmental Engineering, University of Iceland, 145 pp. 978-9935-9473-6-9 https://hdl.handle.net/20.500.11815/1273 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/20.500.11815/1273 |
_version_ |
1766335441720573952 |