Preprints
https://doi.org/10.5194/gmdd-4-2791-2011
https://doi.org/10.5194/gmdd-4-2791-2011

Submitted as: model description paper 24 Oct 2011

Submitted as: model description paper | 24 Oct 2011

Review status: this preprint was under review for the journal GMD. A revision for further review has not been submitted.

Description of EQSAM4: gas-liquid-solid partitioning model for global simulations

S. Metzger1, B. Steil1, L. Xu2, J. E. Penner2, and J. Lelieveld1,3,4 S. Metzger et al.
  • 1Max Planck Institute for Chemistry, Mainz, Germany
  • 2University of Michigan, Ann Arbor, Michigan, USA
  • 3The Cyprus Institute, Nicosia, Cyprus
  • 4King Saud University, Riyadh, Saudi Arabia

Abstract. We introduce version 4 of the EQuilibrium Simplified Aerosol Model (EQSAM4), which is part of our aerosol chemistry-microphysics module (GMXe) and chemistry-climate model (EMAC). We focus on the relative humidity of deliquescence (RHD) based water uptake of atmospheric aerosols, as this is important for atmospheric chemistry and climate modeling, e.g. to calculate the aerosol optical depth (AOD). Since the main EQSAM4 applications will involve large-scale, long-term and high-resolution atmospheric chemistry-climate modeling with EMAC, computational efficiency is an important requirement. EQSAM4 parameterizes the composition and water uptake of multicomponent atmospheric aerosols by considering the gas-liquid-solid partitioning of single and mixed solutes. EQSAM4 builds on analytical, and hence CPU efficient, aerosol hygroscopic growth parameterizations to compute the aerosol liquid water content (AWC). The parameterizations are described in the companion paper (Metzger et al., 2011) and only require a compound specific coefficient νi to derive the single solute molality and the AWC for the whole range of water activity (aw). νi is pre-calculated and applied during runtime by using internal look-up tables. Here, the EQSAM4 equilibrium model is described and compared to the more explicit thermodynamic model ISORROPIA II. Both models are imbedded in EMAC/GMXe. Box model inter-comparisons, including the reference model E-AIM, and global simulations with EMAC show that gas-particle partitioning, including semi-volatiles and water, is in good agreement. A more comprehensive box model inter-comparison of EQSAM4 with EQUISOLV II is subject of the revised publication of Xu et al. (2009), i.e. Xu et al. (2011).

S. Metzger et al.

 
Status: closed (peer review stopped)
Status: closed (peer review stopped)
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Status: closed (peer review stopped)
Status: closed (peer review stopped)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

S. Metzger et al.

S. Metzger et al.

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