Modelling atmospheric OH-reactivity in a boreal forest ecosystem
- 1Division of Atmospheric Sciences, Department of Physics, P.O. Box 48, University of Helsinki, 00014, Finland
- 2Helsinki University Centre for Environment, P.O. Box 27, University of Helsinki, 00014, Finland
- 3Wind Energy Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark, Building 118, Box 49, 4000, Roskilde, Denmark
- 4Max Planck Institute of Chemistry, J. Becher Weg 27, 55128 Mainz, Germany
- 5Indian Institute of Science Education and Research (IISER) Mohali, MGSIPAP Complex, Sector 26, Chandigarh 160019, India
- 6National Center for Atmospheric Research, Boulder, CO 80307, USA
Abstract. We have modelled the total atmospheric OH-reactivity in a boreal forest and investigated the individual contributions from gas phase inorganic species, isoprene, monoterpenes, and methane along with other important VOCs. Daily and seasonal variation in OH-reactivity for the year 2008 was examined as well as the vertical OH-reactivity profile. We have used SOSA; a one dimensional vertical chemistry-transport model (Boy et al., 2011a) together with measurements from Hyytiälä, SMEAR II station, Southern Finland, conducted in August 2008. Model simulations only account for ~30–50% of the total measured OH sink, and in our opinion, the reason for missing OH-reactivity is due to unmeasured unknown BVOCs, and limitations in our knowledge of atmospheric chemistry including uncertainties in rate constants. Furthermore, we found that the OH-reactivity correlates with both organic and inorganic compounds and increases during summer. The summertime canopy level OH-reactivity peaks during night and the vertical OH-reactivity decreases with height.