GLOMAP-mode in UKCA linked to Tropospheric Chemistry (IsopTrop)

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

In addition to the 49 advected tracers in IsopTrop, 11 extra gas phase tracers are added for the aerosol chemistry. These consist of 8 sulphur species (DMS, SO2, MSA, H2SO4, DMSO, CS2, COS, H2S), 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).

Here the aerosol precursor chemistry scheme is as used with the GLOMAP-mode aerosol scheme when run with offline oxidants in the TOMCAT chemistry transport model (see e.g. Mann et al, 2010, Table 1) but with additional chemical products included to ensure conservation of NOx and HOx (see e.g. Breider et al, 2011).

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 IsopTrop chemistry, this extended scheme (IsopTrop+Aero) uses the sparse-matrix Newton-Raphson 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.

Mann, G. W., Carslaw, K. S., Spracklen, D. V. et al: Description and evaluation of GLOMAP-mode: a modal global aerosol microphysics model for the UKCA composition-climate model, Geosci. Model Dev., 3, 519-551, 2010.

Breider, T., PhD thesis, University of Leeds, 2011.