Atmospheric Chemistry and Physics Simulating atmospheric composition over a South-East Asian tropical rainforest: performance of a chemistry box model

Abstract. Atmospheric composition and chemistry above tropical rainforests is currently not well established, particu-larly for south-east Asia. In order to examine our understand-ing of chemical processes in this region, the performance of a box model of atmospheric boundary layer chemistry is tested against measurements made at the top of the rainfor-est canopy near Danum Valley, Malaysian Borneo. Multi-variate optimisation against ambient concentration measure-ments was used to estimate average canopy-scale emissions for isoprene, total monoterpenes and nitric oxide. The ex-cellent agreement between estimated values and measured fluxes of isoprene and total monoterpenes provides confi-dence in the overall modelling strategy, and suggests that this method may be applied where measured fluxes are not avail-able, assuming that the local chemistry and mixing are ade