Articles | Volume 11, issue 18
Research article
20 Sep 2011
Research article |  | 20 Sep 2011

Modelling atmospheric OH-reactivity in a boreal forest ecosystem

D. Mogensen, S. Smolander, A. Sogachev, L. Zhou, V. Sinha, A. Guenther, J. Williams, T. Nieminen, M. K. Kajos, J. Rinne, M. Kulmala, and M. Boy

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.

Final-revised paper