An expert survey on chamber measurement techniques and data handling procedures for methane fluxes

<p>Methane is an important greenhouse gas, but the magnitude of global emissions from natural sources remains highly uncertain. To estimate methane emissions on large spatial scales, methane flux data sets from field measurements collected and processed by many different researchers must be co...

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Main Authors: K. Jentzsch, L. van Delden, M. Fuchs, C. C. Treat
Format: Article
Language:English
Published: Copernicus Publications 2025-06-01
Series:Earth System Science Data
Online Access:https://essd.copernicus.org/articles/17/2331/2025/essd-17-2331-2025.pdf
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author K. Jentzsch
K. Jentzsch
L. van Delden
M. Fuchs
C. C. Treat
C. C. Treat
author_facet K. Jentzsch
K. Jentzsch
L. van Delden
M. Fuchs
C. C. Treat
C. C. Treat
author_sort K. Jentzsch
collection DOAJ
description <p>Methane is an important greenhouse gas, but the magnitude of global emissions from natural sources remains highly uncertain. To estimate methane emissions on large spatial scales, methane flux data sets from field measurements collected and processed by many different researchers must be combined. One common method for obtaining in situ methane flux measurements is flux chambers. We hypothesize that considerable uncertainty might be introduced into data synthesis products derived from chamber measurements due to the variety of measurement setups and data processing and quality control approaches used within the chamber flux community. Existing guidelines on chamber measurements promote more standardized measurement and data processing techniques, but, to our knowledge, so far, no study has investigated which methods are actually used within the chamber flux community. Therefore, we aimed to identify the key discrepancies between the measurement and data handling procedures implemented for chamber methane fluxes by different researchers.</p> <p>We conducted an expert survey to collect information on why, where, and how scientists conduct chamber-based methane flux measurements and how they handle the resulting data. We received 36 responses from researchers in North America, Europe, and Asia, which revealed that 80 % of respondents have adopted multi-gas analyzers to obtain high-frequency (<span class="inline-formula">&lt;</span> 1 Hz) methane concentration measurements over a total chamber closure time of, typically, between 2 and 5 min. Most but not all of the respondents use recommended chamber designs, including features such as airtight sealing, fans, and a pressure vent. We presented a standardized set of methane concentration time series recorded during chamber measurements and derived CH<span class="inline-formula"><sub>4</sub></span> flux estimates based on the processing and quality control approaches suggested by the survey participants. The responses showed broad disagreement among the experts concerning the processes that they consider to be responsible for non-linear methane concentration increases. Furthermore, there was a tendency to discard low or negative CH<span class="inline-formula"><sub>4</sub></span> fluxes. Based on the expert responses, we estimated a variability of 28 %, introduced by different researchers deciding differently on discarding vs. accepting a measurement when processing a representative data set of chamber measurements. Different researchers choosing different time periods within the same measurement for flux calculation caused an additional variability of 17 %. Our study highlights the importance of understanding the processes causing the patterns in CH<span class="inline-formula"><sub>4</sub></span> concentrations visible from high-resolution analyzers, as well as the need for standardized data handling procedures in future chamber methane flux measurements. This is highly important to reliably quantify methane fluxes all over the world.</p> <p>The survey results, as well as the questionnaire, are publicly available at <a href="https://doi.org/10.1594/PANGAEA.971695">https://doi.org/10.1594/PANGAEA.971695</a> (Jentzsch et al., 2024b).</p>
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spelling doaj-art-71ea43aa44624468a4fc74901a4e28022025-08-20T02:02:48ZengCopernicus PublicationsEarth System Science Data1866-35081866-35162025-06-01172331237210.5194/essd-17-2331-2025An expert survey on chamber measurement techniques and data handling procedures for methane fluxesK. Jentzsch0K. Jentzsch1L. van Delden2M. Fuchs3C. C. Treat4C. C. Treat5Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, GermanyInstitute of Environmental Science and Geography, University of Potsdam, Potsdam, GermanyAlfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, GermanyRenewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO, USAAlfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, GermanyDepartment of Agroecology, Aarhus University, Aarhus, Denmark<p>Methane is an important greenhouse gas, but the magnitude of global emissions from natural sources remains highly uncertain. To estimate methane emissions on large spatial scales, methane flux data sets from field measurements collected and processed by many different researchers must be combined. One common method for obtaining in situ methane flux measurements is flux chambers. We hypothesize that considerable uncertainty might be introduced into data synthesis products derived from chamber measurements due to the variety of measurement setups and data processing and quality control approaches used within the chamber flux community. Existing guidelines on chamber measurements promote more standardized measurement and data processing techniques, but, to our knowledge, so far, no study has investigated which methods are actually used within the chamber flux community. Therefore, we aimed to identify the key discrepancies between the measurement and data handling procedures implemented for chamber methane fluxes by different researchers.</p> <p>We conducted an expert survey to collect information on why, where, and how scientists conduct chamber-based methane flux measurements and how they handle the resulting data. We received 36 responses from researchers in North America, Europe, and Asia, which revealed that 80 % of respondents have adopted multi-gas analyzers to obtain high-frequency (<span class="inline-formula">&lt;</span> 1 Hz) methane concentration measurements over a total chamber closure time of, typically, between 2 and 5 min. Most but not all of the respondents use recommended chamber designs, including features such as airtight sealing, fans, and a pressure vent. We presented a standardized set of methane concentration time series recorded during chamber measurements and derived CH<span class="inline-formula"><sub>4</sub></span> flux estimates based on the processing and quality control approaches suggested by the survey participants. The responses showed broad disagreement among the experts concerning the processes that they consider to be responsible for non-linear methane concentration increases. Furthermore, there was a tendency to discard low or negative CH<span class="inline-formula"><sub>4</sub></span> fluxes. Based on the expert responses, we estimated a variability of 28 %, introduced by different researchers deciding differently on discarding vs. accepting a measurement when processing a representative data set of chamber measurements. Different researchers choosing different time periods within the same measurement for flux calculation caused an additional variability of 17 %. Our study highlights the importance of understanding the processes causing the patterns in CH<span class="inline-formula"><sub>4</sub></span> concentrations visible from high-resolution analyzers, as well as the need for standardized data handling procedures in future chamber methane flux measurements. This is highly important to reliably quantify methane fluxes all over the world.</p> <p>The survey results, as well as the questionnaire, are publicly available at <a href="https://doi.org/10.1594/PANGAEA.971695">https://doi.org/10.1594/PANGAEA.971695</a> (Jentzsch et al., 2024b).</p>https://essd.copernicus.org/articles/17/2331/2025/essd-17-2331-2025.pdf
spellingShingle K. Jentzsch
K. Jentzsch
L. van Delden
M. Fuchs
C. C. Treat
C. C. Treat
An expert survey on chamber measurement techniques and data handling procedures for methane fluxes
Earth System Science Data
title An expert survey on chamber measurement techniques and data handling procedures for methane fluxes
title_full An expert survey on chamber measurement techniques and data handling procedures for methane fluxes
title_fullStr An expert survey on chamber measurement techniques and data handling procedures for methane fluxes
title_full_unstemmed An expert survey on chamber measurement techniques and data handling procedures for methane fluxes
title_short An expert survey on chamber measurement techniques and data handling procedures for methane fluxes
title_sort expert survey on chamber measurement techniques and data handling procedures for methane fluxes
url https://essd.copernicus.org/articles/17/2331/2025/essd-17-2331-2025.pdf
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