2012 Progress Report: Particle-Resolved Simulations for Quantifying Black Carbon Climate Impact and Model Uncertainty

EPA Grant Number: R835042
Title: Particle-Resolved Simulations for Quantifying Black Carbon Climate Impact and Model Uncertainty
Investigators: Riemer, Nicole , West, Matthew
Institution: University of Illinois at Urbana-Champaign
EPA Project Officer: Wilson, Wil
Project Period: June 1, 2011 through May 31, 2014 (Extended to May 31, 2015)
Project Period Covered by this Report: June 1, 2012 through May 31,2013
Project Amount: $449,902
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


(1) Calculate key quantities for modeling black carbon eff ects in global and regional climate simulations (including the aging timescale, optical properties, and cloud condensation nuclei (CCN) number); (2) Quantify the uncertainty in these quantities in climate predictions resulting from inadequate representation of black carbon aerosol mixing state in existing models; and (3) Provide a testbed for the evaluation of proposed new approximate aerosol modeling algorithms.

Progress Summary:

In the second year of this project, we targeted the following milestones:
  1. We developed the first quantitative metric for aerosol population mixing state, de fined as the distribution of per-particle chemical species composition. This new metric, the mixing state index χ, is an affine ratio of the average per-particle species diversity and the bulk population species diversity, both of which are based on information-theoretic entropy measures. The mixing state index χ enables the fi rst rigorous de nition of the spectrum of mixing states from so-called external mixture to internal mixture, which is signi cant for aerosol climate impacts, including aerosol optical properties and cloud condensation nuclei activity. This metric will be useful for classifying and comparing scenarios.
  2. We continued our work of designing scenarios based on, and constrained with, data from field campaigns and completed the ship plume study that we had started in Year 1 of the project. To expand our suite of real-world case studies, we identi ed a dataset from the MEGAPOLI 2010 winter campaign in Paris. This represents the first PartMC case study that uses data from an aerosol time-of-flight mass spectrometer (ATOFMS) to constrain the model.
  3. The final signi cant achievement in Year 2 was our continued work on the basic algorithmic methods used in PartMC. Improving these methods is key to enabling larger scenario libraries to be generated, with each scenario using more computational particles to improve accuracy of the key output quantities (e.g., aging timescales). In Year 2, we developed a fast binning method for particle sorting that enables more efficient simulation of particle events, especially coagulation. This work is described in a paper that has been accepted to the SIAM journal on Multiscale Modeling and Simulation.

Future Activities:

The objectives for Year 3 of this project include:
  1. Expand our suite of real-world scenarios: Our next target are scenarios based on the CARES campaign.
  2. Error quanti cation: For the scenarios that we have in place we will compute the error in key quantities due to simplifying assumptions in traditional aerosol models (limited number of size bins, arti dicial internal mixing, etc.)
  3. Recommendations for climate models: We will synthesize the results from the case studies and package them so that they will be useful for climate models.

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

Other project views: All 24 publications 9 publications in selected types All 9 journal articles
Type Citation Project Document Sources
Journal Article Michelotti MD, Heath MT, West M. Binning for efficient stochastic multiscale particle simulations. Multiscale Modeling & Simulation 2013;11(4):1071-1096. R835042 (2012)
R835042 (2013)
R835042 (Final)
  • Abstract: SIAM-Abstract
  • Journal Article Riemer N, West M. Quantifying aerosol mixing state with entropy and diversity measures. Atmospheric Chemistry and Physics 2013;13(22):11423-11439. R835042 (2012)
    R835042 (2013)
    R835042 (Final)
  • Full-text: ACP-Full Text PDF
  • Abstract: ACP-Abstract
  • Journal Article Tian J, Riemer N, West M, Pfaffenberger L, Schlager H, Petzold A. Modeling the evolution of aerosol particles in a ship plume using PartMC-MOSAIC. Atmospheric Chemistry and Physics 2014;14(11):5327-5347. R835042 (2012)
    R835042 (2013)
    R835042 (Final)
  • Full-text: ACP-Full Text PDF
  • Abstract: ACP-Abstract
  • Supplemental Keywords:

    Black carbon aging, particle-resolved model, mixing state

    Progress and Final Reports:

    Original Abstract
    2011 Progress Report
    2013 Progress Report
    Final Report