SOSA – a new model to simulate the concentrations of organic vapours and sulphuric acid inside the ABL – Part 1: Model description and initial evaluation

Abstract

Abstract. Chemistry in the atmospheric boundary layer (ABL) is controlled by complex processes of surface fluxes, flow, turbulent transport, and chemical reactions. We present a new model SOSA (model to simulate the concentration of organic vapours and sulphuric acid) and attempt to reconstruct the emissions, transport and chemistry in the ABL in and above a vegetation canopy using tower measurements from the SMEAR II at Hyytiälä, Finland and available soundings data from neighbouring meteorological stations. Using the sounding data for upper boundary condition and nudging the model to tower measurements in the surface layer we were able to get a reasonable description of turbulence and other quantities through the ABL. As a first application of the model, we present vertical profiles of organic compounds and discuss their relation to newly formed particles.

Oxidation of SO<sub>2</sub> by stabilized Criegee intermediate (sCI) radicals as a crucial source for atmospheric sulfuric acid concentrations

“…In this work we used two different models, MALTE (Model to predict new Aerosol formation in the Lower TropospherE; Boy et al, 2006Boy et al, , 2008Lauros et al, 2011) and SOSA (model to Simulate the concentrations of Organic vapours and Sulfuric Acid; Boy et al, 2011;Mogensen et al, 2011). Although MALTE -similar to SOSA -is a one-dimensional chemistry transport model, we used the latter to investigate the effect of the studied oxidation schemes on temporal trends in concentration profiles for the SMEAR II station in Hyytiälä.…”

“…Included also are standard emission potentials (SEP) for isoprene, α-pinene, β-pinene, 3 -carene, limonene, sabinene, ocimene, farnesene, β-caryophyllene, 2-methyl-3-buten-2-ol, cineole, linalool and unspecified monoterpenes and sesquiterpenes . The emission scheme has been verified by comparing VOC gas concentrations in the papers by Boy et al (2011) and Mogensen et al (2011).…”

“…The one-dimensional chemistry transport model SOSA is described in detail by Boy et al (2011) and Mogensen et al (2011), thus we will only give a brief overview of the model here. SOSA consists of three modules dealing with meteorology, emissions and chemistry.…”

“…The measured input data are obtained from SMEAR II and includes inorganic gas concentrations (NO x , SO 2 and CO) together with condensation sinks for sulfuric acid and nitric acid, based on DMPS and APS data (Boy et al, 2003). The meteorological module is described by a 1-D version of the coupled plant-atmosphere boundary layer model SCADIS (Sogachev et al, 2002(Sogachev et al, , 2005Sogachev and Panferov, 2006;Sogachev, 2009;Boy et al, 2011). SCADIS employs a 1.5 turbulent kinetic energy-specific dissipation closure scheme (including the Reynolds averaged NavierStokes equations for flow) using a number of parameterizations.…”

Particle concentration and flux dynamics in the atmospheric boundary layer as the indicator of formation mechanism

“…However, complex parametrisations may be sensitive to particular parameter values, which may be unreliable. For this study, we have chosen a one-and-half order parametrisation (Boy et al, 2011) which presents mixing more reliably than the earlier utilised first order schemes and is easier to utilise in aerosol flux calculations than the nonlocal schemes mentioned above.…”