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Geoscientific Model Development An interactive open-access journal of the European Geosciences Union
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© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: model description paper 25 Sep 2020

Submitted as: model description paper | 25 Sep 2020

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This preprint is currently under review for the journal GMD.

Development of an atmospheric chemistry model coupled to the PALM model system 6.0: Implementation and first applications

Basit Khan1, Sabine Banzhaf1, Edward C. Chan2,3, Renate Forkel1, Farah Kanani-Sühring4,7, Klaus Ketelsen5, Mona Kurppa6, Björn Maronga4,10, Matthias Mauder1, Siegfried Raasch4, Emmanuele Russo2,8,9, Martijn Schaap2, and Matthias Sühring4 Basit Khan et al.
  • 1Institute of Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology, Garmisch-Partenkirchen, 82467, Germany
  • 2Freie Universität Berlin (FUB), Institute of Meteorology, TrUmF, Germany
  • 3Institute for Advanced Sustainability Studies (IASS), Potsdam, Germany
  • 4Leibniz University Hannover (LUH), Institute of Meteorology and Climatology, Germany
  • 5Independent Software Consultan
  • 6University of Helsinki, Finland
  • 7Harz Energie GmbH & Co. KG, Goslar, Germany
  • 8Climate and Environmental Physics, Physics Institute, University of Bern, Sidlerstrasse 5, 3012, Bern, Switzerland
  • 9Oeschger Centre for Climate Change Research, University of Bern, Hochschulstrasse 4, 3012, Bern, Switzerland
  • 10University of Bergen, Geophysical Institute, Bergen, Norway

Abstract. In this article we describe the implementation of an online-coupled gas-phase chemistry model in the turbulence resolving PALM model system 6.0. The new chemistry model is part of the PALM-4U components (read: PALM for you; PALM for urban applications) which are designed for application of PALM model in the urban environment (Maronga et al., 2020). The latest version of the Kinetic PreProcessor (KPP, 2.2.3), has been utilised for the numerical integration of gas-phase chemical reactions. A number of tropospheric gas-phase chemistry mechanisms of different complexity have been implemented ranging from the photostationary state to more complex mechanisms such as CBM4, which includes major pollutants namely O3, NO, NO2, CO, a simplified VOC chemistry and a small number of products. Further mechanisms can also be easily added by the user. In this work, we provide a detailed description of the chemistry model, its structure along with its various features, input requirements, its application and limitations. A case study is presented to demonstrate the application of the new chemistry model in the urban environment. The computation domain of the case study is comprised of part of Berlin, Germany, covering an area of 6.71 × 6.71 km with a horizontal resolution of 10 m. We used "PARAMETERIZED" emission mode of the chemistry model that only considers emissions from traffic sources. Three chemical mechanisms of varying complexity and one no-reaction (passive) case have been applied and results are compared with observations from two permanent air quality stations in Berlin that fall within the computation domain. The results show importance of online photochemistry and dispersion of air pollutants in the urban boundary layer. The simulated NOx and O3 species show reasonable agreement with observations. The agreement is better during midday and poorest during the evening transition hours and at night. CBM4 and SMOG mechanisms show better agreement with observations than the steady state PHSTAT mechanism.

Basit Khan et al.

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Status: open (until 20 Nov 2020)
Status: open (until 20 Nov 2020)
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Basit Khan et al.

Data sets

Input data for performing chemistry coupled PALM model system 6.0 simulations with different chemical mechanisms Khan, B.

Basit Khan et al.


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Publications Copernicus
Short summary
This article describes the implementation of an online-coupled gas-phase chemistry model in the micro-scale PALM model system 6.0. The model reads emission input and perform transport, chemical transformation and dry deposition of chemical compounds while aerosol processes are described by the sectional aerosol model, SALSA. Several pre-compiled ready-to-use chemical mechanisms are included in the chemistry model code, however, user can also easily implement other mechanisms.
This article describes the implementation of an online-coupled gas-phase chemistry model in the...