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| Titel |
Advancements in Micrometeorological Technique for Monitoring CH4 Release from Remote Permafrost Regions: Principles, Emerging Research, and Latest Updates |
| VerfasserIn |
George Burba, Artem Budishchev, Beniamino Gioli, Sami Haapanala, Manuel Helbig, Salvatore Losacco, Ivan Mammarella, Virginie Moreaux, Patrick Murphy, Walter Oechel, Olli Peltola, Janne Rinne, Oliver Sonnentag, Cove Sturtevant, Timo Vesala, Donatella Zona, Rommel Zulueta |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250087165
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| Publikation (Nr.) |
 EGU/EGU2014-1185.pdf |
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| Zusammenfassung |
| Flux stations have been widely used to monitor release and uptake rates of CO2, CH4, H2O
and other gases from various ecosystems for climate research for over 30 years. The stations
provide accurate and continuous measurements of gas exchange at time scales ranging from
15 or 30 minutes to multiple years, and at spatial scales ranging from thousands m2 to
multiple km2, depending on the measurement height.
The stations can nearly instantaneously detect rapid changes in gas release due to
weather or man-triggered events (pressure changes, ice breakage and melts, ebullition
events, etc.). They can also detect slow changes related to seasonal dynamics and
man-triggered processes (seasonal freeze and thaw, long-term permafrost degradation,
etc.).
From 1980s to mid-2000s, station configuration, data collection and processing were
highly-customized, site-specific and greatly dependent on "school-of-thought" practiced by a
particular researcher. In the past 3-5 years, due to significant efforts of global and regional
flux networks and technological developments, the methodology became fairly
standardized.
Majority of current stations compute gas emission and uptake rates using eddy covariance
method, as one of the most direct micrometeorological techniques. Over 600 such flux
stations operate in over 120 countries, using permanent and mobile towers or moving
platforms (e.g., automobiles, helicopters, airplanes, ships, etc.).
With increasing atmospheric temperatures in the Arctic likely resulting in a higher rate of
permafrost degradation, measurements of gas exchange dynamics become particularly
important. The permafrost regions store a significant amount of organic materials under
anaerobic conditions, leading to large CH4 production and accumulation in the upper layers
of bedrock, soil and ice. These regions may become a significant potential source
of global CH4 release under a warming climate over the following decades and
centuries.
Present measurements of CH4 release in permafrost regions have mostly been made with
static chamber techniques, and few were done with the eddy covariance approach using
closed-path analyzers. Although chambers and closed-path analyzers have advantages, both
techniques have significant limitations, especially for remote or portable research in cold
regions.
Static chamber measurements are discrete in time and space, and particularly
difficult to use over polygonal tundra with highly non-uniform micro-topography and
active soil layer. Closed-path gas analyzers for measuring CH4 eddy fluxes require
climate control, employ high-power pumps, and generally require grid power and
infrastructure.
As a result, spatial coverage of eddy covariance CH4 flux measurements in cold regions
remains limited. Existing stations are often located near grid power sources and roads rather
than in the middle of the methane-producing ecosystem, while those that are placed
appropriately may require extraordinary efforts to build and maintain them, with large
investments into manpower and infrastructure.
In this presentation, basic principles of eddy covariance flux measurements are explained,
along with details on the CH4, CO2 and H2O exchange measurements using low-power flux
stations.
Also included are latest updates on the emerging research utilizing such stations in remote
permafrost regions, and on the 2013-2014 development of fully automated remote unattended
flux station capable of processing data on-the-go to continuously output final CH4 release
rates. |
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