Modeling the multiphase processing of an urban and a rural air mass with COSMO-MUSCAT

Research output: Contribution to journalArticle

Abstract

A reduced version of the complex aqueous phase mechanism CAPRAM3.0i (C3.0RED) was used in the regional chemistry transport model COSMO–MUSCAT in a 2-D application. Besides sulfate and nitrate production, the mechanism treats a complex HOx-chemistry, transition metal ion chemistry and organic species up to C4. The effects of the cloud chemistry on the chemical composition of air and particles were investigated. Sensitivity studies were conducted for an urban and a rural air mass. For this purpose simulations with C3.0RED were compared to ones with a simple inorganic aqueous phase mechanism (INORG) and without aqueous phase chemistry. A reduction of the gas phase concentrations of major oxidants was observed especially in the urban environment. Compared to INORG, C3.0RED is always more acidic leading to shifts in several chemical subsystems, (e.g. production of sulfate). Using C3.0RED instead of INORG, differences in sulfate mass of 3% to −15% occurred. The modeled O/C-ratio tends to be higher than observations as C3.0RED does not consider the whole population of organics and no insoluble organic mass. Nevertheless, the modeled concentration of glyoxalic acid is in the range of atmospheric measurements in both environments, whereas oxalic acid and pyruvic acid are underestimated in the urban case.

Details

Authors
External organisations
  • Leibniz Institute for Tropospheric Research (TROPOS)
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Geochemistry
  • Meteorology and Atmospheric Sciences

Keywords

  • Multiphase cloud chemistry, CAPRAM, Regional modeling, Chemistry transport model, Urban environment
Original languageEnglish
Pages (from-to)720-731
JournalUrban Climate
Volume10
Publication statusPublished - 2014
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes