Configuration for tropospheric chemistry-aerosol simulations

This configuration involves an extension to the UKCA Standard Tropospheric Chemistry (StdTrop) scheme to additionally include tropospheric aerosol-precursor chemistry.

In addition to the 26 advected tracers in StdTrop, 7 extra tracers are added for the aerosol chemistry. These consist of 4 sulphur species (DMS, SO2, MSA, H2SO4, ammonia and two organic species. The two organic species are a monoterpene tracer "MONOTER" and an oxidation product "SECORG" following the simple secondary organic aerosol production scheme developed for the GLOMAP-TOMCAT chemistry transport model (e.g. Spracklen et al, 2006).

The H2SO4 and SECORG tracers condense into the sulphate and organic carbon components in the GLOMAP-mode aerosol scheme.

Aqueous phase oxidation of SO2 by H2O2 and O3 is calculated based on an effective Henry's law approach and produces sulphate in the GLOMAP-mode accumulation and coarse soluble modes.

As for the StdTrop chemistry, this extended scheme (StdTrop+Aero)uses the Backward-Euler solver.

Spracklen, D. V., Carslaw, K. S., Kulmala, M., et al.: The contribution of boundary layer nucleation events to total particle concentrations on regional and global scales, Atmos. Chem. Phys., 6, 5631--5648, doi:10.5194/acp-6-5631-2006, 2006.