Detection and spatiotemporal analysis of methane ebullition on thermokarst lake ice using high-resolution optical aerial imagery

Thermokarst lakes are important emitters of methane, a potent greenhouse gas. However, accurate estimation of methane flux from thermokarst lakes is difficult due to their remoteness and observational challenges associated with the heterogeneous nature of ebullition. We used high-resolution (9–11 cm...

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Published in:Biogeosciences
Main Authors: P. R. Lindgren, G. Grosse, K. M. Walter Anthony, F. J. Meyer
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2016
Subjects:
Online Access:https://doi.org/10.5194/bg-13-27-2016
https://doaj.org/article/c2417701f05d419aa5fddbfe6106d82e
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spelling ftdoajarticles:oai:doaj.org/article:c2417701f05d419aa5fddbfe6106d82e 2023-05-15T16:41:25+02:00 Detection and spatiotemporal analysis of methane ebullition on thermokarst lake ice using high-resolution optical aerial imagery P. R. Lindgren G. Grosse K. M. Walter Anthony F. J. Meyer 2016-01-01T00:00:00Z https://doi.org/10.5194/bg-13-27-2016 https://doaj.org/article/c2417701f05d419aa5fddbfe6106d82e EN eng Copernicus Publications http://www.biogeosciences.net/13/27/2016/bg-13-27-2016.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-13-27-2016 https://doaj.org/article/c2417701f05d419aa5fddbfe6106d82e Biogeosciences, Vol 13, Iss 1, Pp 27-44 (2016) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2016 ftdoajarticles https://doi.org/10.5194/bg-13-27-2016 2022-12-31T12:19:48Z Thermokarst lakes are important emitters of methane, a potent greenhouse gas. However, accurate estimation of methane flux from thermokarst lakes is difficult due to their remoteness and observational challenges associated with the heterogeneous nature of ebullition. We used high-resolution (9–11 cm) snow-free aerial images of an interior Alaskan thermokarst lake acquired 2 and 4 days following freeze-up in 2011 and 2012, respectively, to detect and characterize methane ebullition seeps and to estimate whole-lake ebullition. Bubbles impeded by the lake ice sheet form distinct white patches as a function of bubbling when lake ice grows downward and around them, trapping the gas in the ice. Our aerial imagery thus captured a snapshot of bubbles trapped in lake ice during the ebullition events that occurred before the image acquisition. Image analysis showed that low-flux A- and B-type seeps are associated with low brightness patches and are statistically distinct from high-flux C-type and hotspot seeps associated with high brightness patches. Mean whole-lake ebullition based on optical image analysis in combination with bubble-trap flux measurements was estimated to be 174 ± 28 and 216 ± 33 mL gas m −2 d −1 for the years 2011 and 2012, respectively. A large number of seeps demonstrated spatiotemporal stability over our 2-year study period. A strong inverse exponential relationship ( R 2 > = 0.79) was found between the percent of the surface area of lake ice covered with bubble patches and distance from the active thermokarst lake margin. Even though the narrow timing of optical image acquisition is a critical factor, with respect to both atmospheric pressure changes and snow/no-snow conditions during early lake freeze-up, our study shows that optical remote sensing is a powerful tool to map ebullition seeps on lake ice, to identify their relative strength of ebullition, and to assess their spatiotemporal variability. Article in Journal/Newspaper Ice Sheet Thermokarst Directory of Open Access Journals: DOAJ Articles Biogeosciences 13 1 27 44
institution Open Polar
collection Directory of Open Access Journals: DOAJ Articles
op_collection_id ftdoajarticles
language English
topic Ecology
QH540-549.5
Life
QH501-531
Geology
QE1-996.5
spellingShingle Ecology
QH540-549.5
Life
QH501-531
Geology
QE1-996.5
P. R. Lindgren
G. Grosse
K. M. Walter Anthony
F. J. Meyer
Detection and spatiotemporal analysis of methane ebullition on thermokarst lake ice using high-resolution optical aerial imagery
topic_facet Ecology
QH540-549.5
Life
QH501-531
Geology
QE1-996.5
description Thermokarst lakes are important emitters of methane, a potent greenhouse gas. However, accurate estimation of methane flux from thermokarst lakes is difficult due to their remoteness and observational challenges associated with the heterogeneous nature of ebullition. We used high-resolution (9–11 cm) snow-free aerial images of an interior Alaskan thermokarst lake acquired 2 and 4 days following freeze-up in 2011 and 2012, respectively, to detect and characterize methane ebullition seeps and to estimate whole-lake ebullition. Bubbles impeded by the lake ice sheet form distinct white patches as a function of bubbling when lake ice grows downward and around them, trapping the gas in the ice. Our aerial imagery thus captured a snapshot of bubbles trapped in lake ice during the ebullition events that occurred before the image acquisition. Image analysis showed that low-flux A- and B-type seeps are associated with low brightness patches and are statistically distinct from high-flux C-type and hotspot seeps associated with high brightness patches. Mean whole-lake ebullition based on optical image analysis in combination with bubble-trap flux measurements was estimated to be 174 ± 28 and 216 ± 33 mL gas m −2 d −1 for the years 2011 and 2012, respectively. A large number of seeps demonstrated spatiotemporal stability over our 2-year study period. A strong inverse exponential relationship ( R 2 > = 0.79) was found between the percent of the surface area of lake ice covered with bubble patches and distance from the active thermokarst lake margin. Even though the narrow timing of optical image acquisition is a critical factor, with respect to both atmospheric pressure changes and snow/no-snow conditions during early lake freeze-up, our study shows that optical remote sensing is a powerful tool to map ebullition seeps on lake ice, to identify their relative strength of ebullition, and to assess their spatiotemporal variability.
format Article in Journal/Newspaper
author P. R. Lindgren
G. Grosse
K. M. Walter Anthony
F. J. Meyer
author_facet P. R. Lindgren
G. Grosse
K. M. Walter Anthony
F. J. Meyer
author_sort P. R. Lindgren
title Detection and spatiotemporal analysis of methane ebullition on thermokarst lake ice using high-resolution optical aerial imagery
title_short Detection and spatiotemporal analysis of methane ebullition on thermokarst lake ice using high-resolution optical aerial imagery
title_full Detection and spatiotemporal analysis of methane ebullition on thermokarst lake ice using high-resolution optical aerial imagery
title_fullStr Detection and spatiotemporal analysis of methane ebullition on thermokarst lake ice using high-resolution optical aerial imagery
title_full_unstemmed Detection and spatiotemporal analysis of methane ebullition on thermokarst lake ice using high-resolution optical aerial imagery
title_sort detection and spatiotemporal analysis of methane ebullition on thermokarst lake ice using high-resolution optical aerial imagery
publisher Copernicus Publications
publishDate 2016
url https://doi.org/10.5194/bg-13-27-2016
https://doaj.org/article/c2417701f05d419aa5fddbfe6106d82e
genre Ice Sheet
Thermokarst
genre_facet Ice Sheet
Thermokarst
op_source Biogeosciences, Vol 13, Iss 1, Pp 27-44 (2016)
op_relation http://www.biogeosciences.net/13/27/2016/bg-13-27-2016.pdf
https://doaj.org/toc/1726-4170
https://doaj.org/toc/1726-4189
1726-4170
1726-4189
doi:10.5194/bg-13-27-2016
https://doaj.org/article/c2417701f05d419aa5fddbfe6106d82e
op_doi https://doi.org/10.5194/bg-13-27-2016
container_title Biogeosciences
container_volume 13
container_issue 1
container_start_page 27
op_container_end_page 44
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