Ensemble Analyses of the Impact and Uncertainties of Global Change on Regional Air Quality in the U.S.EPA Grant Number: R833369
Title: Ensemble Analyses of the Impact and Uncertainties of Global Change on Regional Air Quality in the U.S.
Investigators: Lamb, Brian , Theobald, David M. , Guenther, Alex , Wiedinmyer, Christine , Mass, Clifford , McKenzie, Donald , Salathe, Eric
Current Investigators: Lamb, Brian , Guenther, Alex , Wiedinmyer, Christine , Mass, Clifford , McKenzie, Donald , Salathe, Eric , Chung, Sandra
Institution: Washington State University , National Center for Atmospheric Research , USDA , Colorado State University , University of Washington
Current Institution: Washington State University , National Center for Atmospheric Research , USDA , University of Washington
EPA Project Officer: Chung, Serena
Project Period: February 1, 2007 through January 31, 2011 (Extended to January 31, 2012)
Project Amount: $899,987
RFA: Consequences of Global Change For Air Quality (2006) RFA Text | Recipients Lists
Research Category: Climate Change , Air
This proposal builds on results from a current EPA global change project (RD83830962010). Our overall goal is to answer questions, as posed from our current project, related to the effects of global change on continental and regional air quality AND to include quantitative estimates of uncertainties as part of the answers to our research questions. We will employ an ensemble modeling approach with three specific objectives: 1) to develop a quantitative measure of the uncertainty in our modeling framework using ensemble modeling methods in comparison to current 1990-1999 observations; 2) to project these uncertainties into the future for the period 2045-2054 and quantitatively address the uncertainties that accompany projections of future emissions, both global and U.S., including changes in landcover, urbanization, biogenic emissions, and fire emissions; and 3) to continue to address our research questions that will determine the consequences of global change upon U.S. air quality.
Our work plan begins with Bayesian analyses of GCM/WRF/CMAQ model configurations for a base climate period (1990-1999) to produce weighted ensemble members based upon their skill in representing observed climate and air quality. This analysis will reduce the number of ensemble members for future climate runs to those that provide significant skill to the overall composite. This reduced set will be combined with a range of potential emission scenarios in a factorial design, to predict both expected values and uncertainties in future air quality. The CMAQ model will enable us to estimate future air quality conditions in terms of photochemical gas ambient concentrations, levels of fine and coarse particulates, and the deposition rates of N, S, and Hg species. Modeling analyses using WRF/CMAQ will address the continental U.S. with 36-km grid resolution and the Pacific Northwest with 12-km grid resolution. An important aspect of the latter scale will be examination of future impacts in Class 1 wilderness areas, as specified in EPA’s Regional Haze Rule.
The primary products from this work will be model results for current and future decades for the U.S. and the PNW. These will encompass a number of model/emission scenarios so that quantitative estimates of the air quality impact and uncertainties associated with both modeling errors and emission scenarios will be obtained. The use of ensembles will provide a better overall understanding of the potential impact of global change on future air quality. Since we will focus on ozone and particulate matter and we will also address both ambient concentrations and deposition, our results should be of direct benefit to EPA and to our regional agency partners in the NW-AIRQUEST consortium in the Pacific Northwest.