2013 Progress Report: Source Attribution of Radiative Forcing in Chemical Transport Models

EPA Grant Number: R835211
Title: Source Attribution of Radiative Forcing in Chemical Transport Models
Investigators: Henze, Daven K
Institution: University of Colorado at Boulder
EPA Project Officer: Callan, Richard
Project Period: June 1, 2012 through May 31, 2014 (Extended to May 31, 2016)
Project Period Covered by this Report: June 1, 2013 through May 31,2014
Project Amount: $244,446
RFA: Source Attribution of Radiative Forcing in Chemical Transport (2011) RFA Text |  Recipients Lists
Research Category: Global Climate Change , Air Quality and Air Toxics , Climate Change , Air


The project objective is to account for the radiative forcing impacts of aerosols and tropospheric ozone (O3) from changes to their precursor emissions owing to air quality and greenhouse gas policies. This will be accomplished through the following research tasks:

  1. Quantify the impacts of emissions from each sector, in each model grid cell, on the global and regional radiative forcing of tropospheric O3 and aerosols.
  2. Assess the radiative forcing consequences of emissions scenarios designed to target combinations of aerosol and greenhouse gas reductions.

Progress Summary:

During the second year of this project, we worked to expand our use of model and satellite data to relate temperature impacts to spatially resolved emissions of long-lived greenhouse gases, and aerosol and ozone precursors. In the first year, we had estimated global radiative forcing of aerosol and ozone precursor emissions. We had also extended this analysis to consider regional radiative forcing, and started to evaluate the regional temperature response of this forcing using the parameterized climate sensitivities of Shindell et al. (2012). This year, we finished incorporation of the climate sensitivities of Shindell et al. (2012) into our adjoint-based source attribution calculations. We also worked on estimates of combined impacts of aerosol (direct-e ffects only) and greenhouse gases. In our revisions to our paper submitted during the first year, which was published in ES&T (Akhtar et al., 2013), we considered both the Time Integrated Radiative Forcing (TIRF) through 2050, and the 100-year Global Warming Potential. The latter metric emphasizes the role of long-lived greenhouse gases, while the former emphasizes the role of the short-lived species (O3, CH4, and aerosols). 

Our previous work attributing the O3 radiative forcing using the TES Instantaneous Radiative Kernels (IRKs) was limited to the near-term response of O3 to changes in NOx emissions. However, another important response for climate consideration is that CH4 responds to changes in NOx on much longer time scales (10 yrs). Changes in the abundance of CH4 can then also lead to changes in O3 lifetime. This sequence of decadal-scale feedbacks are difficult to capture with our GEOS-Chem adjoint simulations, which are limited to annual-scale calculations. However, we have worked to use parameterizations developed in the literature, as well as multi-model studies from the HTAP project, to estimate (a) the response of the global CH4 to continentally speci fic changes in NOx (Naik et al., 2005) and the zonal RF of CH4 and O3 in response to these changes. 

Future Activities:

The next year will focus on inclusion of indirect and semi-direct aerosol radiative forcing into our source attribution calculations.


Shindell, D., J.C.I. Kuylenstierna, E. Vignati, R. van Dingenen, M. Amann, Z. Klimont, S.C. Anenberg, N. Muller, G. Janssens-Maenhout, F. Raes, J. Schwartz, G. Faluvegi, L. Pozzoli, K. Kupiainen, L. Höglund-Isaksson, L. Emberson, D. Streets, V. Ramanathan, K. Hicks, N.T.K. Oanh, G. Milly, M. Williams, V. Demkine, and D. Fowler, 2012: Simultaneously mitigating near-term climate change and improving human health and food security. Science, 335, 183-189, doi:10.1126/science.1210026

Akhtar, F. H., R. W. Pinder, D. H. Loughlin, and D. K. Henze, GLIMPSE: a rapid decision framework for energy and environmental policy, Environ. Sci. Technol., 47, 12011{12019, doi:10.1021/es402283j, 2013 

Naik, V., Mauzerall, D., Horowitz, L., Schwarzkopf, M.D., Ramaswamy, V., and Oppenheimer, M. Net radiative forcing due to changes in regional emissions of tropospheric ozone precursors. Journal of Geophysical Research. 24 December 2005.

Journal Articles on this Report : 2 Displayed | Download in RIS Format

Other project views: All 15 publications 3 publications in selected types All 3 journal articles
Type Citation Project Document Sources
Journal Article Akhtar FH, Pinder RW, Loughlin DH, Henze DK. GLIMPSE:a rapid decision framework for energy and environmental policy. Environmental Science & Technology 2013;47(21):12011-12019. R835211 (2012)
R835211 (2013)
R835211 (2014)
R835211 (Final)
  • Abstract from PubMed
  • Full-text: Harvard University-Full Text PDF
  • Abstract: ES&T-Abstract
  • Other: ES&T-Full Text PDF
  • Journal Article Lacey F, Henze D. Global climate impacts of country-level primary carbonaceous aerosol from solid-fuel cookstove emissions. Environmental Research Letters 2015;10(11):114003 (10 pp.) R835211 (2013)
    R835211 (2014)
    R835211 (Final)
  • Full-text: Environmental Research Letters-Full Text HTML
  • Abstract: Environmental Research Letters-Abstract
  • Other: Environmental Research Letters-Full Text PDF
  • Supplemental Keywords:

    adjoint sensitivity, environmental policy, air quality regulations, fine particulate matter, climate change, remote sensing;

    Progress and Final Reports:

    Original Abstract
    2012 Progress Report
    2014 Progress Report
    Final Report