Abstract
Abstract. We present a full-year online global simulation of tropospheric chemistry (158 coupled species) at cubed-sphere c720 (∼12.5×12.5km2) resolution in the NASA Goddard Earth Observing System Model version 5 Earth system model (GEOS-5 ESM) with GEOS-Chem as a chemical module (G5NR-chem). The GEOS-Chem module within GEOS uses the exact same code as the offline GEOS-Chem chemical transport model (CTM) developed by a large atmospheric chemistry research community. In this way, continual updates to the GEOS-Chem CTM by that community can be seamlessly passed on to the GEOS chemical module, which remains state of the science and referenceable to the latest version of GEOS-Chem. The 1-year G5NR-chem simulation was conducted to serve as the Nature Run for observing system simulation experiments (OSSEs) in support of the future geostationary satellite constellation for tropospheric chemistry. It required 31 wall-time days on 4707 compute cores with only 24 % of the time spent on the GEOS-Chem chemical module. Results from the GEOS-5 Nature Run with GEOS-Chem chemistry were shown to be consistent to the offline GEOS-Chem CTM and were further compared to global and regional observations. The simulation shows no significant global bias for tropospheric ozone relative to the Ozone Monitoring Instrument (OMI) satellite and is highly correlated with observations spatially and seasonally. It successfully captures the ozone vertical distributions measured by ozonesondes over different regions of the world, as well as observations for ozone and its precursors from the August–September 2013 Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) aircraft campaign over the southeast US. It systematically overestimates surface ozone concentrations by 10 ppbv at sites in the US and Europe, a problem currently being addressed by the GEOS-Chem CTM community and from which the GEOS ESM will benefit through the seamless update of the online code.
Highlights
Integration of atmospheric chemistry into Earth system models (ESMs) has been identified as a frontier for ESM development (National Research Council, 2012) and is a priority science area for atmospheric chemistry research (National Academies of Sciences, Engineering, and Medicine, 2016)
Models of atmospheric chemistry are rapidly evolving, and an atmospheric chemistry module within an ESM must be able to readily update to the state of the science. We have developed such a capability by integrating the Goddard Earth Observing System with chemistry (GEOS-Chem) chemical transport model (CTM) as a comprehensive and seamlessly updatable atmospheric chemistry module in the NASA GEOS ESM (Long et al, 2015)
Results from the GEOS version 5 (GEOS-5) Nature Run with GEOS-Chem chemistry are compared to observations for ozone and NOx, CO, peroxyacetyl nitrate (PAN), and formaldehyde (HCHO), and to the GEOS-Chem CTM
Summary
Integration of atmospheric chemistry into Earth system models (ESMs) has been identified as a frontier for ESM development (National Research Council, 2012) and is a priority science area for atmospheric chemistry research (National Academies of Sciences, Engineering, and Medicine, 2016). GEOS-Chem (http://geos-chem.org) is an open-source global 3-D Eulerian model of atmospheric chemistry driven by GEOS-5 assimilated meteorological data It includes state-of-the-science capabilities for tropospheric and stratospheric gas–aerosol chemistry (Eastham et al, 2014; Hu et al, 2017), with additional capabilities for aerosol microphysics (Yu and Luo, 2009; Trivitayanurak et al, 2008). We have developed the capability to efficiently integrate the GEOS-Chem chemical module into ESMs in a way that enables seamless updating to the latest standard version of GEOS-Chem This involved transformation of GEOS-Chem into a grid-independent and Earth system modeling framework (ESMF)-compliant model (Long et al, 2015). We compare the model outputs with coarse offline GEOSChem CTM results and with independent observations for tropospheric ozone and precursors as a test of fidelity and increased power We refer to this VHR simulation as the GEOS-5 Nature Run with GEOS-Chem chemistry, or G5NRchem
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call