Arctic Thermokarst Lake Behaviour: Quantifying Change through Automatic Pixel Classification in Google Earth Engine and the Landsat Archive
Thermokarst lakes cover an estimated 20-40% of Earth’s 14x106 km2 of permafrost. Increasing thermokarst lake size is often used as a proxy for permafrost degradation and associated methane emissions. Lack of long-term, high frequency observations has led to poor quantification of changes in thermoka...
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2024
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ftunivexeter:oai:ore.exeter.ac.uk:10871/137355 2024-10-06T13:47:04+00:00 Arctic Thermokarst Lake Behaviour: Quantifying Change through Automatic Pixel Classification in Google Earth Engine and the Landsat Archive Barnett, H Hill, Tim Palmer, Steven Hinojosa, Jessica 2024 http://hdl.handle.net/10871/137355 en eng University of Exeter Geography http://hdl.handle.net/10871/137355 2026-03-09 This thesis is embargoed until 09/Mar/2026 as the author plans to publish their research. http://www.rioxx.net/licenses/all-rights-reserved Remote sensing GIS Permafrost Thermokarst Lake Google Earth Engine (GEE) Landsat Methane Cryosphere Thesis or dissertation MScbyRes in Physcial Geography Masters MbyRes Dissertation 2024 ftunivexeter 2024-09-17T14:21:27Z Thermokarst lakes cover an estimated 20-40% of Earth’s 14x106 km2 of permafrost. Increasing thermokarst lake size is often used as a proxy for permafrost degradation and associated methane emissions. Lack of long-term, high frequency observations has led to poor quantification of changes in thermokarst lake size as a potential result of climate change. In this study, a scalable and reproducible automatic workflow for water pixel classification was developed in Google Earth Engine using the entire 50-year Landsat archive, and was applied to thermokarst lake ecosystems to detect long-term changes in regional lake fractional area. Two lake area datasets were produced in regionally contrasting study sites: a 45-year dataset in Tuktoyaktuk, Canada and, due to lack of available imagery, a 23-year database for Siberian lakes on the border of the Sakha Republic in Russia. Tuktoyaktuk, a region of extensive thermokarst activity, has a high percentage of thermokarst lake area enabling rigorous testing of the detection algorithm. The fast warming of the region’s permafrost allows a narrative to be established using Landsat timeseries. The lakes near Sakha Republic were chosen based on high Landsat image availability to test the wider applicability of the workflow in geographically varying permafrost regions. Water pixel identification had a 93% accuracy compared to published datasets. Lake coverage in Tuktoyaktuk is higher, with lakes covering on average 20.7% more of the total area. Both areas had overall increases in fractional lake area, with Tuktoyaktuk recording a 3.5 times greater increase. Annual rates of expansion are increasing at 0.23% in Tuktoyaktuk and 0.49% in the Siberian study site. Estimated total emissions from both sites over their respective time periods was 1.58x106 tCH4, or 44.24x106 tCO2e. Key drivers of lake area change require more research, but both sites demonstrated strong positive correlation with freezing height anomaly and sea surface temperature anomaly. Future work should focus on applying ... Master Thesis Arctic Climate change permafrost Sakha Republic Thermokarst University of Exeter: Open Research Exeter (ORE) Arctic Sakha Canada Tuktoyaktuk ENVELOPE(-133.006,-133.006,69.425,69.425) |
institution |
Open Polar |
collection |
University of Exeter: Open Research Exeter (ORE) |
op_collection_id |
ftunivexeter |
language |
English |
topic |
Remote sensing GIS Permafrost Thermokarst Lake Google Earth Engine (GEE) Landsat Methane Cryosphere |
spellingShingle |
Remote sensing GIS Permafrost Thermokarst Lake Google Earth Engine (GEE) Landsat Methane Cryosphere Barnett, H Arctic Thermokarst Lake Behaviour: Quantifying Change through Automatic Pixel Classification in Google Earth Engine and the Landsat Archive |
topic_facet |
Remote sensing GIS Permafrost Thermokarst Lake Google Earth Engine (GEE) Landsat Methane Cryosphere |
description |
Thermokarst lakes cover an estimated 20-40% of Earth’s 14x106 km2 of permafrost. Increasing thermokarst lake size is often used as a proxy for permafrost degradation and associated methane emissions. Lack of long-term, high frequency observations has led to poor quantification of changes in thermokarst lake size as a potential result of climate change. In this study, a scalable and reproducible automatic workflow for water pixel classification was developed in Google Earth Engine using the entire 50-year Landsat archive, and was applied to thermokarst lake ecosystems to detect long-term changes in regional lake fractional area. Two lake area datasets were produced in regionally contrasting study sites: a 45-year dataset in Tuktoyaktuk, Canada and, due to lack of available imagery, a 23-year database for Siberian lakes on the border of the Sakha Republic in Russia. Tuktoyaktuk, a region of extensive thermokarst activity, has a high percentage of thermokarst lake area enabling rigorous testing of the detection algorithm. The fast warming of the region’s permafrost allows a narrative to be established using Landsat timeseries. The lakes near Sakha Republic were chosen based on high Landsat image availability to test the wider applicability of the workflow in geographically varying permafrost regions. Water pixel identification had a 93% accuracy compared to published datasets. Lake coverage in Tuktoyaktuk is higher, with lakes covering on average 20.7% more of the total area. Both areas had overall increases in fractional lake area, with Tuktoyaktuk recording a 3.5 times greater increase. Annual rates of expansion are increasing at 0.23% in Tuktoyaktuk and 0.49% in the Siberian study site. Estimated total emissions from both sites over their respective time periods was 1.58x106 tCH4, or 44.24x106 tCO2e. Key drivers of lake area change require more research, but both sites demonstrated strong positive correlation with freezing height anomaly and sea surface temperature anomaly. Future work should focus on applying ... |
author2 |
Hill, Tim Palmer, Steven Hinojosa, Jessica |
format |
Master Thesis |
author |
Barnett, H |
author_facet |
Barnett, H |
author_sort |
Barnett, H |
title |
Arctic Thermokarst Lake Behaviour: Quantifying Change through Automatic Pixel Classification in Google Earth Engine and the Landsat Archive |
title_short |
Arctic Thermokarst Lake Behaviour: Quantifying Change through Automatic Pixel Classification in Google Earth Engine and the Landsat Archive |
title_full |
Arctic Thermokarst Lake Behaviour: Quantifying Change through Automatic Pixel Classification in Google Earth Engine and the Landsat Archive |
title_fullStr |
Arctic Thermokarst Lake Behaviour: Quantifying Change through Automatic Pixel Classification in Google Earth Engine and the Landsat Archive |
title_full_unstemmed |
Arctic Thermokarst Lake Behaviour: Quantifying Change through Automatic Pixel Classification in Google Earth Engine and the Landsat Archive |
title_sort |
arctic thermokarst lake behaviour: quantifying change through automatic pixel classification in google earth engine and the landsat archive |
publisher |
University of Exeter |
publishDate |
2024 |
url |
http://hdl.handle.net/10871/137355 |
long_lat |
ENVELOPE(-133.006,-133.006,69.425,69.425) |
geographic |
Arctic Sakha Canada Tuktoyaktuk |
geographic_facet |
Arctic Sakha Canada Tuktoyaktuk |
genre |
Arctic Climate change permafrost Sakha Republic Thermokarst |
genre_facet |
Arctic Climate change permafrost Sakha Republic Thermokarst |
op_relation |
http://hdl.handle.net/10871/137355 |
op_rights |
2026-03-09 This thesis is embargoed until 09/Mar/2026 as the author plans to publish their research. http://www.rioxx.net/licenses/all-rights-reserved |
_version_ |
1812175325879074816 |