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Eddy covariance measurements of CO2 and sensible and latent heat fluxes during a full year in a boreal pine forest trunk-space.

Authors :
Launiainen, Samuli
Rinne, Janne
Pumpanen, Jukka
Kulmala, Liisa
Kolari, Pasi
Keronen, Petri
Siivola, Erkki
Pohja, Toivo
Hari, Pertti
Vesala, Timo
Source :
Boreal Environment Research; 2005, Vol. 10 Issue 6, p569-588, 20p, 1 Diagram, 9 Graphs
Publication Year :
2005

Abstract

The eddy covariance method was used to determine turbulent heat fluxes and CO<subscript>2</subscript> flux below a boreal Scots pine canopy 3 m above the forest floor. Data were filtered using standard deviation of the vertical velocity as a measure of the turbulent mixing in the trunk space along with the non-stationary criterion. The turbulent transfer in the trunk space was dominated by large (15–100 m) intermittent eddies, which were detectable by the eddy covariance technique. Heat fluxes exhibited clear annual and diurnal course and amounted to 20%–30% of the fluxes above the canopy. The forest floor was a source of carbon all-year-round and the CO<subscript>2</subscript> efflux was mainly controlled by soil temperature. Photosynthesis of the forest floor vegetation decreased daytime fluxes of CO<subscript>2</subscript> by 1.0–1.5 μmol m<superscript>-2</superscript> s<superscript>-1</superscript> compared with nocturnal values (∼3.0 μmol m<superscript>-2</superscript> s<superscript>-1</superscript>). The eddy covariance method provided a similar daily cycle to the chamber method but there was a discrepancy between their mean levels. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
12396095
Volume :
10
Issue :
6
Database :
Supplemental Index
Journal :
Boreal Environment Research
Publication Type :
Academic Journal
Accession number :
22868510