Considerations for measuring ground CO 2 effluxes with chambers

This paper considers the factors that influence ground CO 2 fluxes as measured by the chamber method. New data and published results are used to illustrate the effects of various factors on CO 2 emissions from the ground. These factors are: pressure differences between the ambient air and the chambe...

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Bibliographic Details
Published inChemical geology Vol. 177; no. 1; pp. 3 - 13
Main Authors Welles, J.M, Demetriades-Shah, T.H, McDermitt, D.K
Format Journal Article
LanguageEnglish
Published Elsevier B.V 2001
Subjects
Carbon dioxide
Flux
Respiration
Soil gases
Carbon dioxide
Flux
Soil gases
Respiration
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Summary:This paper considers the factors that influence ground CO 2 fluxes as measured by the chamber method. New data and published results are used to illustrate the effects of various factors on CO 2 emissions from the ground. These factors are: pressure differences between the ambient air and the chamber, wind speed within the chamber, the chamber CO 2 concentration relative to ambient air concentration and the accumulation of water vapor in the chamber. A mathematical analysis of the accumulation of CO 2 in the chamber in terms of diffusion and advection (e.g., air flow out of the ground at geothermal degassing locations) shows that the same protocol should be followed, whether the mechanism of emission is purely by diffusion or by a combination of diffusion and advection. The analysis also yields a simple way for estimating soil CO 2 conductance and the soil CO 2 concentration at the depth of insertion of the chamber into the ground.
ISSN:0009-2541
1872-6836
DOI:10.1016/S0009-2541(00)00388-0