Journal cover Journal topic
Geoscientific Model Development An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/gmd-2017-94
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Development and technical paper
03 May 2017
Review status
A revision of this discussion paper is under review for the journal Geoscientific Model Development (GMD).
Improved method for linear carbon monoxide simulation and source attribution in atmospheric chemistry models illustrated using GEOS-Chem v9
Jenny A. Fisher1,2, Lee T. Murray3, Dylan B. A. Jones4,5, and Nicholas M. Deutscher1 1Centre for Atmospheric Chemistry, School of Chemistry, University of Wollongong, NSW, Australia
2School of Earth and Environmental Sciences, University of Wollongong, NSW, Australia
3Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY, USA
4Department of Physics, University of Toronto, Toronto, ON, Canada
5Joint Institute for Regional Earth System Science and Engineering, University of California, Los Angeles, CA, USA
Abstract. Carbon monoxide (CO) simulation in atmospheric chemistry models is frequently used for source-receptor analysis, emission inversion, interpretation of observations, and chemical forecasting due to its computational efficiency and ability to quantitatively link simulated CO burdens to sources. While several methods exist for modelling CO source attribution, most are inappropriate for regions where the CO budget is dominated by secondary production rather than direct emissions. Here, we introduce a major update to the linear CO-only capability in the GEOS-Chem chemical transport model that for the first time allows source-region tagging of secondary CO produced from oxidation of non-methane volatile organic compounds. Our updates also remove fundamental inconsistencies between the CO-only simulation and the standard full chemistry simulation by using consistent CO production rates in both. We find that relative to the standard chemistry simulation, CO in the original CO-only simulation was overestimated by more than 100 ppb in the model surface layer and underestimated in outflow regions. The improved CO-only simulation largely resolves these discrepancies by improving both the magnitude and location of secondary production. Despite large differences between the original and improved simulations, however, model evaluation with the global dataset used to benchmark GEOS-Chem shows negligible change to the model's ability to match the observations. This suggests that the current GEOS-Chem benchmark is not well suited to evaluate model changes in regions influenced by biogenic emissions and chemistry, and expanding the dataset to include observations from biogenic source regions (including those from recent aircraft campaigns) should be a priority for the GEOS-Chem community. Using Australasia as a case study, we show that the new ability to geographically tag secondary CO production provides significant added value for interpreting observations and model results in regions where primary CO emissions are low. Secondary production dominates the CO budget across much of the world, especially in the southern hemisphere, and we recommend future model-observation and multi-model comparisons implement this capability to provide a more complete understanding of CO sources and their variability.

Citation: Fisher, J. A., Murray, L. T., Jones, D. B. A., and Deutscher, N. M.: Improved method for linear carbon monoxide simulation and source attribution in atmospheric chemistry models illustrated using GEOS-Chem v9, Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2017-94, in review, 2017.
Jenny A. Fisher et al.
Jenny A. Fisher et al.
Jenny A. Fisher et al.

Viewed

Total article views: 406 (including HTML, PDF, and XML)

HTML PDF XML Total Supplement BibTeX EndNote
324 66 16 406 12 5 20

Views and downloads (calculated since 03 May 2017)

Cumulative views and downloads (calculated since 03 May 2017)

Viewed (geographical distribution)

Total article views: 406 (including HTML, PDF, and XML)

Thereof 402 with geography defined and 4 with unknown origin.

Country # Views %
  • 1

Saved

Discussed

Latest update: 25 Jul 2017
Publications Copernicus
Download
Short summary
Carbon monoxide (CO) simulation in atmospheric chemistry models is used for source-receptor analysis, emission inversion, and interpretation of observations. We introduce a major update to CO simulation in the GEOS-Chem chemical transport model that removes fundamental inconsistencies relative to the standard model, resolving biases of more than 100 ppb and errors in vertical structure. We also add source-tagging of secondary CO and demonstrate it provides added value in low-emission regions.
Carbon monoxide (CO) simulation in atmospheric chemistry models is used for source-receptor...
Share