2012 Progress Report: Improved Prediction of the Vertical Profile of Atmospheric Black Carbon: Development and Evaluation of WRF-CMAQ

EPA Grant Number: R835041
Title: Improved Prediction of the Vertical Profile of Atmospheric Black Carbon: Development and Evaluation of WRF-CMAQ
Investigators: Carlton, Annmarie
Institution: Rutgers, The State University of New Jersey
EPA Project Officer: Hunt, Sherri
Project Period: September 1, 2011 through August 31, 2014 (Extended to February 29, 2016)
Project Period Covered by this Report: September 1, 2011 through August 31,2012
Project Amount: $449,916
RFA: Black Carbon's Role In Global To Local Scale Climate And Air Quality (2010) RFA Text |  Recipients Lists
Research Category: Global Climate Change , Climate Change , Air

Objective:

To improve the model predictions of the vertical profile of particulate carbon through better representation of condensed phase organic chemistry in the 3-dimensional photochemical model "CMAQ."

Progress Summary:

The project goals for the first year were to expand the Lim aqueous phase chemical mechanism to include new organic reactions, develop reduced but explicit chemical mechanisms and yield-based parameterizations for in-cloud SOA formation. Further, we proposed to test droplet size partitioning assumptions currently employed in CMAQ's aqueous chemistry routine in box model applications.

The Lim mechanism has been expanded to include the glycoaldehyde oxidation reactions. We are to working to create a condensed version of the Lim mechanism that is consistent and compatible with the organic species present in SAPRC07. We developed and applied yield-based aqueous phase SOA to a series of 14 smog chamber experiments conducted at the University of North Carolina. We found that regardless of SOA mechanism (e.g., Odum 2-product model or volatility basis set), unless we applied specific gas phase formation of water-soluble compounds followed by SOA yields based on aqueous chemistry, we could not reproduce observed trends in SOA. Presentations by Parikh et al., explain this work in detail (listed with links below).

We currently have two operational aqueous chemistry box models that simulate the mechanism in CMAQv4.7.1's aqueous chemistry routine. One box model uses an ROS3 solver and one developed with collaborators at Univ. of Iowa uses an RODAS3 solver within the kinetic pre processor (KPP) framework. Note that the current version of aqchem.F in CMAQ employs a hard coded Forward Euler solver. The models we have developed are more generalized and can be edited (e.g., organic chemistry can be expanded) more readily. We have performed a variety of box model simulations for droplet size sensitivity simulations to investigate the effects of implementing kinetic partitioning (more realistic), instead of CMAQ's current instantaneous Henry's Law assumption. Preliminary results suggest the sulfur(IV) + H2O2 oxidation reaction is sensitive to the assumed droplet size. Even when the kinetic approach uses a droplet diameter of 10um (the current implicit assumption in CMAQ), model predictions of sulfate aerosol are different from the base CMAQ simulation. The second year tasks focus on implementing these box models into a full CMAQ simulation and we are currently in the process of accomplishing this.

Upon developing new organic aqueous phase chemical mechanisms and presenting these findings at AGU, we began a collaboration with NOAA's Geophysical Fluid Dynamics Laboratory (GFDL). We have helped their model developers better represent organic cloud chemistry. There are presentations and publications, with Junfeng Liu, attributed to this extension in the STAR grant objectives and they are listed with links below. This collaboration is exciting because now that GFDL climate model includes this organic cloud chemistry, our expanded mechanism will be included in the next round of model simulations for the IPCC.

Future Activities:

Year 2 activities are focused on implementation in 3-dimensional photochemical model of the new box models.


Journal Articles on this Report : 3 Displayed | Download in RIS Format

Other project views: All 50 publications 17 publications in selected types All 17 journal articles
Type Citation Project Document Sources
Journal Article He C, Liu J, Carlton AG, Fan S, Horowitz LW, Levy II H, Tao S. Evaluation of factors controlling global secondary organic aerosol production from cloud processes. Atmospheric Chemistry and Physics Discussions 2012;12(10):26929-26961. R835041 (2012)
  • Full-text: Atmospheric Chemistry and Physics Discussions - Full Text PDF
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  • Abstract: Atmospheric Chemistry and Physics Discussions
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  • Journal Article Liu J, Horowitz LW, Fan S, Carlton AG, Levy II H. Global in-cloud production of secondary organic aerosols: implementation of a detailed chemical mechanism in the GFDL atmospheric model AM3. Journal of Geophysical Research-Atmospheres 2012;117(15):D15303. R835041 (2012)
    R835041 (Final)
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  • Abstract: Wiley-Abstract & Full-text HTML
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  • Journal Article Parikh HM, Carlton AG, Zhou Y, Zhang H, Kamens RM, Vizuete W. Modeling secondary organic aerosol formation from xylene and aromatic mixtures using a dynamic partitioning approach incorporating particle aqueous-phase chemistry (II). Atmospheric Environment 2012;56:250-260. R835041 (2012)
    R835041 (Final)
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  • Abstract: ScienceDirect-Abstract
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  • Other: ScienceDirect-Full-text PDF
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  • Supplemental Keywords:

    cloud processing, secondary organic aerosol

    Relevant Websites:

    http://envsci.rutgers.edu/~acarlton Exit
    http://climate.envsci.rutgers.edu/SOAS Exit

    Progress and Final Reports:

    Original Abstract
    2013 Progress Report
    2014 Progress Report
    2015 Progress Report
    Final Report