HR: 09:00h
AN: A21A-05    [PDF]
TI: Uptake of Nitrogen Dioxide by Quercus robur - is There a Compensation Point?
AU: * Thielmann, A
EM: athielm@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Biogeochemistry Dept., PO Box 3060, Mainz, 55020 Germany
AU: Chaparro, G
EM: gchaparro@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Biogeochemistry Dept., PO Box 3060, Mainz, 55020 Germany
AU: Kuhn, U
EM: kuhn@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Biogeochemistry Dept., PO Box 3060, Mainz, 55020 Germany
AU: Dindorf, T
EM: dindorf@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Biogeochemistry Dept., PO Box 3060, Mainz, 55020 Germany
AU: Lehmann, L
EM: llehmann@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Biogeochemistry Dept., PO Box 3060, Mainz, 55020 Germany
AU: Kortner, M
EM: MichaelKortner@web.de
AF: Max Planck Institute for Chemistry, Biogeochemistry Dept., PO Box 3060, Mainz, 55020 Germany
AU: Tritsch, C
EM: CHT76@gmx.de
AF: Max Planck Institute for Chemistry, Biogeochemistry Dept., PO Box 3060, Mainz, 55020 Germany
AU: Kesselmeier, J
EM: jks@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Biogeochemistry Dept., PO Box 3060, Mainz, 55020 Germany
AU: Meixner, F X
EM: meixner@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Biogeochemistry Dept., PO Box 3060, Mainz, 55020 Germany
AB: Within the German Atmospheric-Research-Program 2000, the project ECHO (Emission and CHemical Transformation of Biogenic Volatile Organic Compounds) has been carried out in a mixed forest stand during the summer of 2002. The contribution of the Max Planck Institute for Chemistry was the complete characterization of the NOx-flux within the forest, including (a) the quantification of the biogenic NO-release from forest soils, (b) the measurement of the vertical distribution of NOx within and above the canopy and (c) the turbulent transport within and above the forest. The profile measurements allow to identify the participating processes: soil NO emission and subsequent titration of emitted NO by ozone, advection of highly polluted air masses to the site and the uptake of nitrogen dioxide within the crown area. The latter, i.e. the role of vegetation in the NOx-budget within a particular ecosystem is still a matter in controversy, which translates into considerable uncertainties in the global NOx-budget. To assess this issue, dynamic cuvette measurements were performed on a Quercus robur branch. The concurrent measurement of plant physiological (leaf temperature, stomatal conductance, transpiration and photosynthesis/respiration) and ambient parameters (radiation, ambient NOx mixing ratios) allows to put the exchange rate into context. The question whether a compensation point may be identified will especially be addressed.
DE: 0315 Biosphere/atmosphere interactions
DE: 0322 Constituent sources and sinks
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting