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

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Measurement of air-sea methane fluxes in the Baltic Sea using the eddy covariance method
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.ORCID iD: 0000-0003-3740-9507
Show others and affiliations
2019 (English)In: Frontiers in Earth Science, ISSN 2296-6463, Vol. 7, article id 93Article in journal (Refereed) Published
Abstract [en]

Methane (CH4) is the second-most important greenhouse gas in the atmosphere having a significant effect on global climate. The ocean-particularly the coastal regions-have been recognized to be a net source of CH4, however, the constraints on temporal and spatial resolution of CH4 measurements have been the limiting factor to estimate the total oceanic contributions. In this study, the viability of micrometeorological methods for the analysis of CH4 fluxes in the marine environment was evaluated. We present 1 year of semi-continuous eddy covariance measurements of CH4 atmospheric dry mole fractions and air-sea CH4 flux densities at the Ostergarnsholm station at the east coast of the Gotland Island in the central Baltic Sea. The mean annual CH4 flux density was positive, indicating that the region off Gotland is a net source of CH4 to the atmosphere with monthly mean flux densities ranging between -0.1 and 36 nmol m(-2)s(-1). Both the air-water concentration gradient and the wind speed were found to be crucial parameters controlling the flux. The results were in good agreement with other measurements in the Baltic Sea reported in the MEMENTO database. Our results suggest that the eddy covariance technique is a useful tool for studying CH4 fluxes and improving the understanding of air-sea gas exchange processes with high-temporal resolution. Potentially, the high resolution of micrometeorological data can increase the understanding of the temporal variability and forcing processes of CH4 flux.

Place, publisher, year, edition, pages
2019. Vol. 7, article id 93
National Category
Meteorology and Atmospheric Sciences
Identifiers
URN: urn:nbn:se:uu:diva-382883DOI: 10.3389/feart.2019.00093ISI: 000467258000001OAI: oai:DiVA.org:uu-382883DiVA, id: diva2:1313684
Funder
Swedish Research Council FormasSwedish Research Council, 2012-03902Swedish Research Council, 2013-02044Available from: 2019-05-06 Created: 2019-05-06 Last updated: 2020-05-07Bibliographically approved
In thesis
1. Mechanisms controlling air-sea gas exchange in the Baltic Sea
Open this publication in new window or tab >>Mechanisms controlling air-sea gas exchange in the Baltic Sea
2020 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Carbon plays a major role in physical and biogeochemical processes in the atmosphere, the biosphere, and the ocean. CO2 and CH4 are two of the most common carbon-containing compounds in the atmosphere, also recognized as major greenhouse gases. The exchange of CO2 and CH4 between the ocean and the atmosphere is an essential part of the global carbon cycle. The exchange is controlled by the air–sea concentration gradient and by the efficiency of the transfer processes. The lack of knowledge about the forcing mechanisms affecting the exchange of these climate-relevant gases is a major source of uncertainty in the estimation of the global oceanic contributions. Quantifying and understanding the air–sea exchange processes is essential to constrain the estimates and to improve our knowledge about the current and future climate. In this thesis, the mechanisms controlling the air–sea gas exchange in the Baltic Sea are investigated.

The viability of micrometeorological techniques for CH4 monitoring in a coastal environment is evaluated. One year of semi-continuous measurements of air–sea CH4 fluxes using eddy covariance measurements suggests that the method is useful for CH4 flux estimations in marine environments. The measurements allow long-term monitoring at high frequency rates, thus, capturing the temporal variability of the flux. The region off Gotland is a net source of CH4, with both the air–sea concentration gradient and the wind as controlling mechanisms.

A sensitivity analysis of the gas transfer velocity is performed to evaluate the effect of the forcing mechanisms controlling the air–sea CO2 exchange in the Baltic Sea. This analysis shows that the spatio-temporal variability of CO2 fluxes is strongly modulated by water-side convection, precipitation, and surfactants. The effect of these factors is relevant both at regional and global scales, as they are not included in the current budget estimates.

Place, publisher, year, edition, pages
Uppsala universitet, 2020. p. 39
Keywords
Air-sea gas exchange, Baltic Sea, CO2 flux, methane flux
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-409744 (URN)
Presentation
2020-06-10, Norrland I, Geocentrum, Villavägen 16, Uppsala, 14:00 (English)
Opponent
Supervisors
Available from: 2020-05-19 Created: 2020-04-28 Last updated: 2020-05-19Bibliographically approved

Open Access in DiVA

fulltext(5703 kB)6 downloads
File information
File name FULLTEXT01.pdfFile size 5703 kBChecksum SHA-512
7e9506543a9e65782eb35a77297af987012819ad804fe39760e63f2437d9954a666ced15f674f5acd0d6923aaf49c5e72a6132ce3da702baba07b3b16b25cda4
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Authority records BETA

Gutiérrez Loza, LuciaSahlée, ErikNilsson, Erik O.Rutgersson, Anna

Search in DiVA

By author/editor
Gutiérrez Loza, LuciaWallin, MarcusSahlée, ErikNilsson, Erik O.Rutgersson, Anna
By organisation
LUVAL
In the same journal
Frontiers in Earth Science
Meteorology and Atmospheric Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 6 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

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 79 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf