The Role of Land Cover Classes and Rainfall Events on the Active Layer Thermal Regime in the High Arctic
The active layer’s thermal regime, which includes surface energy exchanges and soil thawing/freezing characteristics, is sensitive to environmental factors and processes, and has important implications on biogeochemical, hydrological and geomorphic processes. High Arctic land cover classes were hypo...
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ftqueensuniv:oai:qspace.library.queensu.ca:1974/29024 2023-05-15T14:49:55+02:00 The Role of Land Cover Classes and Rainfall Events on the Active Layer Thermal Regime in the High Arctic Rahman, Tabatha Lamoureux, Scott Geography and Planning 2021-08-16T21:26:08Z http://hdl.handle.net/1974/29024 eng eng Canadian theses http://hdl.handle.net/1974/29024 Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada ProQuest PhD and Master's Theses International Dissemination Agreement Intellectual Property Guidelines at Queen's University Copying and Preserving Your Thesis This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. Attribution 3.0 United States http://creativecommons.org/licenses/by/3.0/us/ CC-BY Active layer Canadian High Arctic Permafrost Subsurface thermal regime Land cover class Rainfall thesis 2021 ftqueensuniv 2021-08-21T23:02:06Z The active layer’s thermal regime, which includes surface energy exchanges and soil thawing/freezing characteristics, is sensitive to environmental factors and processes, and has important implications on biogeochemical, hydrological and geomorphic processes. High Arctic land cover classes were hypothesized to affect the active layer’s thermal regime because they represent variations in environmental factors (e.g., vegetation cover, snow cover and soil moisture content). The objectives of this research were to fill knowledge gaps on the: 1) relationship between land cover classes and active layer thermal regimes, and on the 2) role of rainfall on active layer temperatures in the High Arctic. To address these objectives, air temperature, precipitation, soil temperature and soil moisture data were recorded within three land cover classes (polar semi-desert, mesic tundra and wet sedge) at the Cape Bounty Arctic Watershed Observatory (CBAWO), Nunavut, between 2012 and 2019. The data were used to calculate surface energy exchange (n-factors, surface offsets), mean annual ground temperature at 15 cm depth (MAGT15cm), mean annual ground temperature at the top of permafrost (TTOP), and empirical and modelled maximum thaw depth (MTD). The data were also used to determine characteristics of soil thawing and freezing, ground ice formation and melt, and the active layer’s thermal responses to rainfall. Results showed significant (p < 0.05) interclass differences in n-factors between all three land cover classes. However, MAGT15cm, TTOP and MTD were not significantly different (p > 0.05) between land cover classes (excluding wet sedge where MTD was not calculated), and the empirical MTD was consistently shallower than the modelled MTD. The soil temperature responses to rainfall were consistent between land cover classes and mostly consisted of a dampening of peak diel soil temperatures and a convergence of temperatures with depth. This study was unsuccessful at identifying ice formation and melt within the active layer by purely thermal measures. These results improve our understanding of the relationships between High Arctic land cover classes, rainfall events and the active layer thermal regime, which is critical for our ability to accurately model and predict hydrological and biogeochemical processes, permafrost degradation and landscape stability in continuous permafrost regions. M.Sc. Thesis Arctic Ice Nunavut permafrost Tundra Queen's University, Ontario: QSpace Arctic Cape Bounty ENVELOPE(-109.542,-109.542,74.863,74.863) Nunavut |
institution |
Open Polar |
collection |
Queen's University, Ontario: QSpace |
op_collection_id |
ftqueensuniv |
language |
English |
topic |
Active layer Canadian High Arctic Permafrost Subsurface thermal regime Land cover class Rainfall |
spellingShingle |
Active layer Canadian High Arctic Permafrost Subsurface thermal regime Land cover class Rainfall Rahman, Tabatha The Role of Land Cover Classes and Rainfall Events on the Active Layer Thermal Regime in the High Arctic |
topic_facet |
Active layer Canadian High Arctic Permafrost Subsurface thermal regime Land cover class Rainfall |
description |
The active layer’s thermal regime, which includes surface energy exchanges and soil thawing/freezing characteristics, is sensitive to environmental factors and processes, and has important implications on biogeochemical, hydrological and geomorphic processes. High Arctic land cover classes were hypothesized to affect the active layer’s thermal regime because they represent variations in environmental factors (e.g., vegetation cover, snow cover and soil moisture content). The objectives of this research were to fill knowledge gaps on the: 1) relationship between land cover classes and active layer thermal regimes, and on the 2) role of rainfall on active layer temperatures in the High Arctic. To address these objectives, air temperature, precipitation, soil temperature and soil moisture data were recorded within three land cover classes (polar semi-desert, mesic tundra and wet sedge) at the Cape Bounty Arctic Watershed Observatory (CBAWO), Nunavut, between 2012 and 2019. The data were used to calculate surface energy exchange (n-factors, surface offsets), mean annual ground temperature at 15 cm depth (MAGT15cm), mean annual ground temperature at the top of permafrost (TTOP), and empirical and modelled maximum thaw depth (MTD). The data were also used to determine characteristics of soil thawing and freezing, ground ice formation and melt, and the active layer’s thermal responses to rainfall. Results showed significant (p < 0.05) interclass differences in n-factors between all three land cover classes. However, MAGT15cm, TTOP and MTD were not significantly different (p > 0.05) between land cover classes (excluding wet sedge where MTD was not calculated), and the empirical MTD was consistently shallower than the modelled MTD. The soil temperature responses to rainfall were consistent between land cover classes and mostly consisted of a dampening of peak diel soil temperatures and a convergence of temperatures with depth. This study was unsuccessful at identifying ice formation and melt within the active layer by purely thermal measures. These results improve our understanding of the relationships between High Arctic land cover classes, rainfall events and the active layer thermal regime, which is critical for our ability to accurately model and predict hydrological and biogeochemical processes, permafrost degradation and landscape stability in continuous permafrost regions. M.Sc. |
author2 |
Lamoureux, Scott Geography and Planning |
format |
Thesis |
author |
Rahman, Tabatha |
author_facet |
Rahman, Tabatha |
author_sort |
Rahman, Tabatha |
title |
The Role of Land Cover Classes and Rainfall Events on the Active Layer Thermal Regime in the High Arctic |
title_short |
The Role of Land Cover Classes and Rainfall Events on the Active Layer Thermal Regime in the High Arctic |
title_full |
The Role of Land Cover Classes and Rainfall Events on the Active Layer Thermal Regime in the High Arctic |
title_fullStr |
The Role of Land Cover Classes and Rainfall Events on the Active Layer Thermal Regime in the High Arctic |
title_full_unstemmed |
The Role of Land Cover Classes and Rainfall Events on the Active Layer Thermal Regime in the High Arctic |
title_sort |
role of land cover classes and rainfall events on the active layer thermal regime in the high arctic |
publishDate |
2021 |
url |
http://hdl.handle.net/1974/29024 |
long_lat |
ENVELOPE(-109.542,-109.542,74.863,74.863) |
geographic |
Arctic Cape Bounty Nunavut |
geographic_facet |
Arctic Cape Bounty Nunavut |
genre |
Arctic Ice Nunavut permafrost Tundra |
genre_facet |
Arctic Ice Nunavut permafrost Tundra |
op_relation |
Canadian theses http://hdl.handle.net/1974/29024 |
op_rights |
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada ProQuest PhD and Master's Theses International Dissemination Agreement Intellectual Property Guidelines at Queen's University Copying and Preserving Your Thesis This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. Attribution 3.0 United States http://creativecommons.org/licenses/by/3.0/us/ |
op_rightsnorm |
CC-BY |
_version_ |
1766320997777014784 |