Evaluating simplified chemical mechanisms within present-day simulations of the Community Earth System Model version 1.2 with CAM4 (CESM1.2 CAM-chem): MOZART-4 vs. Reduced Hydrocarbon vs. Super-Fast chemistry
Name
gmd-11-4155-2018.pdf
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6.75 MB
Format
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Checksum (MD5)
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Author(s)
Tilmes, Simone
Emmons, Louisa
Lamarque, Jean-François
Cameron-Smith, Philip
Brown-Steiner, Benjamin E
Selin, Noelle E
Prinn, Ronald G
Date Issued
October 2018
Journal
Geoscientific Model Development
Publisher
Copernicus GmbH
Citation
Brown-Steiner, Benjamin et al. “Evaluating Simplified Chemical Mechanisms Within Present-Day Simulations of the Community Earth System Model Version 1.2 with CAM4 (CESM1.2 CAM-Chem): MOZART-4 Vs. Reduced Hydrocarbon Vs. Super-Fast Chemistry.” Geoscientific Model Development 11, 10 (October 2018): 4155–4174 © 2018 Author(s)
Version
Final published version
Abstract
While state-of-the-art complex chemical mechanisms expand our understanding of atmospheric chemistry, their sheer size and computational requirements often limit simulations to short lengths or ensembles to only a few members. Here we present and compare three 25-year present-day offline simulations with chemical mechanisms of different levels of complexity using the Community Earth System Model (CESM) Version 1.2 CAM-chem (CAM4): the Model for Ozone and Related Chemical Tracers, version 4 (MOZART-4) mechanism, the Reduced Hydrocarbon mechanism, and the Super-Fast mechanism. We show that, for most regions and time periods, differences in simulated ozone chemistry between these three mechanisms are smaller than the model-observation differences themselves. The MOZART-4 mechanism and the Reduced Hydrocarbon are in close agreement in their representation of ozone throughout the troposphere during all time periods (annual, seasonal, and diurnal). While the Super-Fast mechanism tends to have higher simulated ozone variability and differs from the MOZART-4 mechanism over regions of high biogenic emissions, it is surprisingly capable of simulating ozone adequately given its simplicity. We explore the trade-offs between chemical mechanism complexity and computational cost by identifying regions where the simpler mechanisms are comparable to the MOZART-4 mechanism and regions where they are not. The Super-Fast mechanism is 3 times as fast as the MOZART-4 mechanism, which allows for longer simulations or ensembles with more members that may not be feasible with the MOZART-4 mechanism given limited computational resources.
MIT Department
Massachusetts Institute of Technology. Center for Global Change Science
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Massachusetts Institute of Technology. Institute for Data, Systems, and Society
Massachusetts Institute of Technology. Joint Program on the Science & Policy of Global Change
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.5194/gmd-11-4155-2018
