Grid-stretching capability for the GEOS-Chem 13.0.0 atmospheric chemistry model

Geoscientific Model Development, Vol. 14 (2021)

Keywords
Authors
  • L. Bindle
  • Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, USA
  • L. Bindle
  • Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada
  • R. V. Martin
  • Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, USA
  • R. V. Martin
  • Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada
  • R. V. Martin
  • Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA
  • M. J. Cooper
  • Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, USA
  • M. J. Cooper
  • Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada
  • E. W. Lundgren
  • John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
  • S. D. Eastham
  • Laboratory for Aviation and the Environment, Massachusetts Institute of Technology, Cambridge, MA, USA
  • B. M. Auer
  • Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • T. L. Clune
  • Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • H. Weng
  • Laboratory for Climate and Ocean–Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing, China
  • J. Lin
  • Laboratory for Climate and Ocean–Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing, China
  • L. T. Murray
  • Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY, USA
  • J. Meng
  • Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, USA
  • J. Meng
  • Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada
  • J. Meng
  • Atmospheric and Oceanic Sciences, University of California, Los Angeles, Los Angeles, CA, USA
  • C. A. Keller
  • Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • C. A. Keller
  • Universities Space Research Association, Columbia, MD, USA
  • W. M. Putman
  • Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • S. Pawson
  • Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • D. J. Jacob
  • John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA

Abstract

Modeling atmospheric chemistry at fine resolution globally is computationally expensive; the capability to focus on specific geographic regions using a multiscale grid is desirable. Here, we develop, validate, and demonstrate stretched grids in the GEOS-Chem atmospheric chemistry model in its high-performance implementation (GCHP). These multiscale grids are specified at runtime by four parameters that offer users nimble control of the region that is refined and the resolution of the refinement. We validate the stretched-grid simulation versus global cubed-sphere simulations. We demonstrate the operation and flexibility of stretched-grid simulations with two case studies that compare simulated tropospheric NO2 column densities from stretched-grid and cubed-sphere simulations to retrieved column densities from the TROPOspheric Monitoring Instrument (TROPOMI). The first case study uses a stretched grid with a broad refinement covering the contiguous US to produce simulated columns that perform similarly to a C180 (∼ 50 km) cubed-sphere simulation at less than one-ninth the computational expense. The second case study experiments with a large stretch factor for a global stretched-grid simulation with a highly localized refinement with ∼10 km resolution for California. We find that the refinement improves spatial agreement with TROPOMI columns compared to a C90 cubed-sphere simulation of comparable computational demands. Overall, we find that stretched grids in GEOS-Chem are a practical tool for fine-resolution regional- or continental-scale simulations of atmospheric chemistry. Stretched grids are available in GEOS-Chem version 13.0.0.

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