uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Comparison of floating chamber and eddy covariance measurements of lake greenhouse gas fluxes
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. (AWEP)
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. (AWEP)
Linköpings University.
Lund University.
Show others and affiliations
2014 (English)In: Biogeosciences Discussions, ISSN 1810-6277, E-ISSN 1810-6285, Vol. 11, 4225-4233 p.Article in journal (Refereed) Published
Abstract [en]

Fluxes of carbon dioxide (CO2) and methane (CH4) from lakes may have a large impact on the magnitude of the terrestrial carbon sink. Traditionally lake fluxes have been measured using the floating chamber (FC) technique; however, several recent studies use the eddy covariance (EC) method. We present simultaneous flux measurements using both methods at lake Tämnaren in Sweden during field campaigns in 2011 and 2012. Only very few similar studies exist. For CO2 flux, the two methods agree relatively well during some periods, but deviate substantially at other times. The large discrepancies might be caused by heterogeneity of partial pressure of CO2 (pCO2w) in the EC flux footprint. The methods agree better for CH4 fluxes. It is, however, clear that short-term discontinuous FC measurements are likely to miss important high flux events.

Place, publisher, year, edition, pages
2014. Vol. 11, 4225-4233 p.
National Category
Natural Sciences Earth and Related Environmental Sciences Meteorology and Atmospheric Sciences Climate Research Geosciences, Multidisciplinary
URN: urn:nbn:se:uu:diva-229778DOI: 10.5194/bg-11-4225-2014ISI: 000341104400012OAI: oai:DiVA.org:uu-229778DiVA: diva2:737570
Available from: 2014-08-13 Created: 2014-08-13 Last updated: 2015-03-11Bibliographically approved
In thesis
1. Lake Fluxes of Methane and Carbon Dioxide
Open this publication in new window or tab >>Lake Fluxes of Methane and Carbon Dioxide
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Methane (CH4) and carbon dioxide (CO2) are two important greenhouse gases. Recent studies have shown that lakes, although they cover a small area of the globe, can be very important natural sources of atmospheric CH4 and CO2. It is therefore important to monitor the fluxes of these gases between lakes and the atmosphere in order to understand the processes that govern the exchange.

By using the eddy covariance method for lake flux studies, the resolution in time and in space of the fluxes is increased, which gives more information on the governing processes.

Eddy covariance measurements at a Swedish lake revealed a diel cycle in the fluxes of both CH4 and CO2, with higher fluxes during nighttime than daytime. The high nighttime CO2 fluxes could to a large extent be explained with enhanced transfer velocities due to waterside convection. For the diel cycle of CH4 flux it was suggested that waterside convection could enhance the transfer velocity, transport CH4 rich water to the surface, as well as trigger ebullition.

Simultaneous flux measurements of CH4 and CO2 have been presented using both the eddy covariance method and the floating chambers method of which the latter is the traditional measuring method for lake fluxes. For CO2 the two methods agreed well during some periods but differed considerably during others. Disagreement between the methods might be due to horizontal heterogeneity in partial pressure of CO2 in the lake. The methods agreed better for the CH4 flux measurements. However, it is clear that due to the discontinuous nature of the floating chambers, this method will likely miss important high flux events.

The main conclusions of this thesis are:

1) the two gas flux methods are not directly comparable and should be seen as supplementary to each other

2) waterside convection enhances the fluxes of both CH4 and CO2 over the water-air surface. If gas flux measurements are not conducted during nighttime, potential high flux periods might be missed and estimates of the total amount of gas released from lakes to the atmosphere may be biased.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2015. 41 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1221
air-lake gas exchange, carbon dioxide, eddy covariance, floating chambers, methane, waterside convection
National Category
Natural Sciences Meteorology and Atmospheric Sciences
Research subject
urn:nbn:se:uu:diva-241984 (URN)978-91-554-9152-9 (ISBN)
Public defence
2015-03-20, Hambergsalen, Villavägen 16, Uppsala, 10:00 (English)
Available from: 2015-02-26 Created: 2015-01-19 Last updated: 2015-03-18Bibliographically approved

Open Access in DiVA

fulltext(172 kB)283 downloads
File information
File name FULLTEXT01.pdfFile size 172 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Search in DiVA

By author/editor
Podgrajsek, EvaSahlée, ErikLars, TranvikRutgersson, Anna
By organisation
In the same journal
Biogeosciences Discussions
Natural SciencesEarth and Related Environmental SciencesMeteorology and Atmospheric SciencesClimate ResearchGeosciences, Multidisciplinary

Search outside of DiVA

GoogleGoogle Scholar
Total: 283 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 606 hits
ReferencesLink to record
Permanent link

Direct link