Forced and Unforced Permafrost Changes in the Northern Hemisphere during 1901-2100
Permafrost regions are very sensitive to rapid changes in climate and environment. In recent decades, there has been growing interest to better understand the permafrost degradation over the Northern Hemisphere in the context of human-induced climate change. Understanding permafrost dynamics is not...
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ftunivarkansas:oai:scholarworks.uark.edu:etd-5844 2023-11-12T03:59:22+01:00 Forced and Unforced Permafrost Changes in the Northern Hemisphere during 1901-2100 Guo, Hong 2021-12-01T08:00:00Z application/pdf https://scholarworks.uark.edu/etd/4294 https://scholarworks.uark.edu/context/etd/article/5844/viewcontent/Guo_uark_0011A_14589.pdf unknown ScholarWorks@UARK https://scholarworks.uark.edu/etd/4294 https://scholarworks.uark.edu/context/etd/article/5844/viewcontent/Guo_uark_0011A_14589.pdf Graduate Theses and Dissertations Active layer thickness Circumpolar Active Layer Monitoring North Atlantic North Pacific Permafrost Climate Environmental Indicators and Impact Assessment Natural Resources and Conservation Nature and Society Relations Physical and Environmental Geography text 2021 ftunivarkansas 2023-10-30T09:53:59Z Permafrost regions are very sensitive to rapid changes in climate and environment. In recent decades, there has been growing interest to better understand the permafrost degradation over the Northern Hemisphere in the context of human-induced climate change. Understanding permafrost dynamics is not only important for infrastructure but also for environmental protection in cold regions. In-situ permafrost measurements are important for assessing permafrost conditions. However, direct permafrost observations are sparse and asymmetrical in both spatial and temporal coverage. Active layer thickness (ALT) modeling is another approach that can overcome many of these limitations, but the models have large uncertainty in predicting future permafrost changes.This doctoral research firstly investigated the impacts of climate forcings on active layer thickness changes over Alaska since 1990 based on data derived from the in-situ Circumpolar Active Layer Monitoring (CALM) measurements. The results suggested that changes in ALT over Alaskan permafrost regions were not only controlled by warming in regional temperature but were also influenced by large-scale atmospheric and oceanic forcings, particularly in the North Atlantic and North Pacific. Meanwhile, an obvious gap was found between simulated and observed active layer thickness, indicating potential uncertainty in model simulations. To quantify these uncertainties, detection and attribution analyses were applied based on simulations made with CESM-LENS and CMIP6 models across the permafrost regions in the northern hemisphere. For a single model (CESM), the multiple ensemble simulations average showed that the deepening ALT during the historical period was generally small over most of the Northern Hemisphere permafrost zone, except in the western Siberia, Mongolia, and portions of the Canadian Arctic. The deepening trends in ALT are projected to increase under the most extreme RCP8.5 scenario and would be two to four times greater than the observed historical trend in ... Text Active layer monitoring Active layer thickness Arctic Climate change North Atlantic permafrost Alaska Siberia University of Arkansas: ScholarWorks@UARK Arctic Pacific |
institution |
Open Polar |
collection |
University of Arkansas: ScholarWorks@UARK |
op_collection_id |
ftunivarkansas |
language |
unknown |
topic |
Active layer thickness Circumpolar Active Layer Monitoring North Atlantic North Pacific Permafrost Climate Environmental Indicators and Impact Assessment Natural Resources and Conservation Nature and Society Relations Physical and Environmental Geography |
spellingShingle |
Active layer thickness Circumpolar Active Layer Monitoring North Atlantic North Pacific Permafrost Climate Environmental Indicators and Impact Assessment Natural Resources and Conservation Nature and Society Relations Physical and Environmental Geography Guo, Hong Forced and Unforced Permafrost Changes in the Northern Hemisphere during 1901-2100 |
topic_facet |
Active layer thickness Circumpolar Active Layer Monitoring North Atlantic North Pacific Permafrost Climate Environmental Indicators and Impact Assessment Natural Resources and Conservation Nature and Society Relations Physical and Environmental Geography |
description |
Permafrost regions are very sensitive to rapid changes in climate and environment. In recent decades, there has been growing interest to better understand the permafrost degradation over the Northern Hemisphere in the context of human-induced climate change. Understanding permafrost dynamics is not only important for infrastructure but also for environmental protection in cold regions. In-situ permafrost measurements are important for assessing permafrost conditions. However, direct permafrost observations are sparse and asymmetrical in both spatial and temporal coverage. Active layer thickness (ALT) modeling is another approach that can overcome many of these limitations, but the models have large uncertainty in predicting future permafrost changes.This doctoral research firstly investigated the impacts of climate forcings on active layer thickness changes over Alaska since 1990 based on data derived from the in-situ Circumpolar Active Layer Monitoring (CALM) measurements. The results suggested that changes in ALT over Alaskan permafrost regions were not only controlled by warming in regional temperature but were also influenced by large-scale atmospheric and oceanic forcings, particularly in the North Atlantic and North Pacific. Meanwhile, an obvious gap was found between simulated and observed active layer thickness, indicating potential uncertainty in model simulations. To quantify these uncertainties, detection and attribution analyses were applied based on simulations made with CESM-LENS and CMIP6 models across the permafrost regions in the northern hemisphere. For a single model (CESM), the multiple ensemble simulations average showed that the deepening ALT during the historical period was generally small over most of the Northern Hemisphere permafrost zone, except in the western Siberia, Mongolia, and portions of the Canadian Arctic. The deepening trends in ALT are projected to increase under the most extreme RCP8.5 scenario and would be two to four times greater than the observed historical trend in ... |
format |
Text |
author |
Guo, Hong |
author_facet |
Guo, Hong |
author_sort |
Guo, Hong |
title |
Forced and Unforced Permafrost Changes in the Northern Hemisphere during 1901-2100 |
title_short |
Forced and Unforced Permafrost Changes in the Northern Hemisphere during 1901-2100 |
title_full |
Forced and Unforced Permafrost Changes in the Northern Hemisphere during 1901-2100 |
title_fullStr |
Forced and Unforced Permafrost Changes in the Northern Hemisphere during 1901-2100 |
title_full_unstemmed |
Forced and Unforced Permafrost Changes in the Northern Hemisphere during 1901-2100 |
title_sort |
forced and unforced permafrost changes in the northern hemisphere during 1901-2100 |
publisher |
ScholarWorks@UARK |
publishDate |
2021 |
url |
https://scholarworks.uark.edu/etd/4294 https://scholarworks.uark.edu/context/etd/article/5844/viewcontent/Guo_uark_0011A_14589.pdf |
geographic |
Arctic Pacific |
geographic_facet |
Arctic Pacific |
genre |
Active layer monitoring Active layer thickness Arctic Climate change North Atlantic permafrost Alaska Siberia |
genre_facet |
Active layer monitoring Active layer thickness Arctic Climate change North Atlantic permafrost Alaska Siberia |
op_source |
Graduate Theses and Dissertations |
op_relation |
https://scholarworks.uark.edu/etd/4294 https://scholarworks.uark.edu/context/etd/article/5844/viewcontent/Guo_uark_0011A_14589.pdf |
_version_ |
1782329107258802176 |