Publication Abstracts

Wiser et al. 2022, submitted

Wiser, F., B. Place, S. Sen, H.O.T. Pye, B. Yang, D.M. Westervelt, D.K. Henze, A.M. Fiore, and V.F. McNeill, 2022: AMORE-Isoprene v1.0: A new reduced mechanism for gas-phase isoprene oxidation. Geosci. Model Dev., submitted, doi:10.5194/gmd-2022-240.

Gas-phase oxidation of isoprene by ozone (O3) and the hydroxyl (OH) and nitrate (NO3) radicals significantly impacts tropospheric oxidant levels and secondary organic aerosol formation. The most comprehensive and up to date chemical mechanism for isoprene oxidation consists of several hundred species and over 800 reactions. Therefore, the computational expense of including the entire mechanism in large-scale atmospheric chemical transport models is usually prohibitive, and most models employ reduced isoprene mechanisms ranging in size from ∼10 to ∼200 species. We have developed a new reduced isoprene oxidation mechanism using a directed graph path-based automated model reduction approach, with minimal manual adjustment of the output mechanism. The approach takes as inputs a full isoprene oxidation mechanism, the environmental parameter space, and a list of priority species which are protected from elimination during the reduction process. Our reduced mechanism, AMORE-Isoprene, consists of 12 species which are unique to the isoprene mechanism and 22 reactions. We demonstrate its performance in a box model in comparison with experimental data from the literature and other current isoprene oxidation mechanisms. AMORE-Isoprene's performance for predicting the time evolution of isoprene oxidation products, including isoprene epoxydiols (IEPOX) and formaldehyde, is favorable compared to other similarly sized mechanisms. When AMORE-Isoprene is included in the Community Regional Atmospheric Chemistry Multiphase Mechanism 1.0 (CRACMM1AMORE) in CMAQ v5.3.3, O3 and formaldehyde agreement with EPA Air Quality System observations are improved. O3 bias is reduced by 3.4 pbb under daytime conditions for O3 concentrations over 50 ppb. Formaldehyde bias is reduced by 0.26 ppb on average for all formaldehyde measurements compared to the base CRACMM1. There was no significant change in computation time between CRACMM1AMORE and the base CRACMM. AMORE-Isoprene shows a 35% improvement in agreement between simulated IEPOX concentrations and chamber data over the base CRACMM1 mechanism when compared in the F0AM box model framework. This work demonstrates the potential value of automated model reduction for complex reaction systems.

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BibTeX Citation

  author={Wiser, F. and Place, B. and Sen, S. and Pye, H. O. T. and Yang, B. and Westervelt, D. M. and Henze, D. K. and Fiore, A. M. and McNeill, V. F.},
  title={AMORE-Isoprene v1.0: A new reduced mechanism for gas-phase isoprene oxidation},
  journal={Geosci. Model Dev.},
  note={Manuscript submitted for publication}

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RIS Citation

ID  - wi03500b
AU  - Wiser, F.
AU  - Place, B.
AU  - Sen, S.
AU  - Pye, H. O. T.
AU  - Yang, B.
AU  - Westervelt, D. M.
AU  - Henze, D. K.
AU  - Fiore, A. M.
AU  - McNeill, V. F.
PY  - 2022
TI  - AMORE-Isoprene v1.0: A new reduced mechanism for gas-phase isoprene oxidation
JA  - Geosci. Model Dev.
DO  - 10.5194/gmd-2022-240
ER  -

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