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 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 existing and proposed U.S. regulations for air quality and greenhouse gas mitigation.


The first task will be carried out by augmenting a chemical transport model to quantify the relationship between changes to longwave and shortwave radiative uxes and perturbations to concentrations of O3 and aerosols, respectively. This information will come from new vertically resolved remote sensing observations of the radiative effects of tropospheric O3 from TES, and from online radiative transfer sensitivity calculations for aerosols. Adjoint sensitivities will then be employed to propagate these relationships back- wards through the chemical transport model to impacts from geospatially and sectorally resolved sources. For the second task, these radiative forcing attributions will be used to quickly estimate the radiative impacts of a number of different emissions scenarios, considering those designed to address air quality goals (such as PM2.5 NAAQS and CAIR) as well as greenhouse gas mitigation strategies (CO2 emissions caps).

Expected Results:

The immediate project result is quantification of the pre-industrial to present forcing for anthropogenic emissions, the radiative effects of natural emissions, and spatial distribution of the radiative forcing efficiency for key aerosol and O3 precursors (i.e., mW/m2 per emission). The latter result can be applied to quickly approximate the radiative impacts of future emissions scenarios without preforming additional global model simulations. Such an estimation tool affords analysis of a broad range of scenarios as a means to explore propagation of uncertainties in these scenarios themselves. Further, knowing the degree to which changes in radiative forcing from aerosols and O3 owing to air quality regulations will o set or augment the radiative forcing goals of greenhouse gas mitigation e orts will allow for modulation of such policies to account for the impacts on climate through associated changes to short lived climate forcers (SLCFs). This may ultimately facilitate the design of emissions scenarios that effectively address both climate and air quality goals.

Publications and Presentations:

Publications have been submitted on this project: View all 15 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 3 journal articles for this project

Supplemental Keywords:

receptor modeling, environmental policy, one particulate matter, satellite data, data assimilation, pubic health, inverse modeling;

Progress and Final Reports:

  • 2012 Progress Report
  • 2013 Progress Report
  • 2014 Progress Report
  • Final Report