Grantee Research Project Results
2005 Progress Report: Impacts of Climate Change and Global Emissions on US Air Quality: Development of an Integrated Modeling Framework and Sensitivity Assessment
EPA Grant Number: R830961Title: Impacts of Climate Change and Global Emissions on US Air Quality: Development of an Integrated Modeling Framework and Sensitivity Assessment
Investigators: Adams, Peter , Pandis, Spyros N.
Institution: Carnegie Mellon University
EPA Project Officer: Chung, Serena
Project Period: March 23, 2003 through March 22, 2006 (Extended to March 22, 2007)
Project Period Covered by this Report: March 23, 2005 through March 22, 2006
Project Amount: $900,000
RFA: Assessing the Consequences of Global Change for Air Quality: Sensitivity of U.S. Air Quality to Climate Change and Future Global Impacts (2002) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Air , Climate Change
Objective:
The objectives of this project are as follows:
(1) Develop a comprehensive modeling system for the description of the interactions between climate and local/regional air quality. This system will use a global climate-chemistry model, a regional meteorological model, and a regional air quality model to describe the relevant timescales (hours to decades) and length-scales (kilometers to global scales). It also will include an emissions processing system that will estimate climate-dependent emissions.
(2) Determine the sensitivity of ozone, particulate matter, acid deposition, and visibility to individual meteorological parameters by performing a set of sensitivity experiments in the context of regional chemical transport models (Particulate Matter Comprehensive Air Quality Model with Extensions [PMCAMx] and Community Multiscale Air Quality [CMAQ] model).
(3) Evaluate the ability of the modeling system to describe current air quality in the United States, including annual average pollutant concentrations, their probability distributions, and the frequency of extreme air pollution episodes.
(4) Develop a set of future (year 2050) scenarios (meteorological fields, emissions, and chemical boundary conditions). These scenarios will include climate change and/or global emissions changes and will bound the space of system responses (best-, mean, and worst-case scenarios).
(5) Use the comprehensive modeling system and these scenarios to assess air quality in the year 2050 with and without climate change and with and without changes in global emissions.
(6) Investigate reduced form models and methodologies for incorporating the effects of climate change and global emission changes in future planning and assessment.
Progress Summary:
In this past year, progress towards achieving the above goals was made along several fronts:
Regional Chemical Transport Model Simulations of Sensitivity to Climate Parameters
Over the past year, a number of simulations have been performed and analyzed to evaluate the impact of climate change on annual average fine particulate matter (PM2.5) concentrations. Four 10-day periods have been modeled so that all four seasons can be examined: 12-21 July 2001, 1-10 October 2001, 6-15 January 2002, and 1-10 April 2002. For each season, a base case and a suite of sensitivity simulations are performed. Each sensitivity simulation tests a single meteorological variable by perturbing it a given amount. The perturbed variables include temperature, wind speed, absolute humidity, mixing height, cloud liquid water content and optical depth, cloudy area, precipitation rate, and precipitating area. Except for cloud, precipitation, and mixing height changes, all perturbations are imposed uniformly in space and time on the modeling domain.
A manuscript describing the seasonal response of PM2.5 to the full suite of meteorological parameters is under preparation.
Results from Global Climate-Chemistry Simulations
In the past year, we have moved from analyzing the global and annual average response in ozone and PM2.5 to analyzing seasonal and regional scale ozone responses. Several conclusions result from this work. First, despite the fact that the global and annual average ozone burden decreases with the increasing humidity in our future climate simulations, a more complex response occurs in polluted regions. Summertime ozone increases occur over Europe and North America, but the increase is larger over North America. The different responses can largely be attributed to isoprene in the southeastern United States. Temperature-sensitive isoprene emissions increase in the model in this area leading to stronger ozone increases than seen in other polluted areas. Second, the frequency of ozone episodes (defined as any time step in which a grid cell exceeds 80 ppbv ozone) increases in our future simulations. An analysis of 5 present and 5 future years indicates that the increased episode frequency is statistically significant with respect to interannual variability. Finally, an analysis of interannual variability with the global model indicates that we will likely need to simulate on the order of 3-5 present and future years with the fully coupled global-regional system (see the next section) to separate the climate change response from simple interannual variability.
Development of a Coupled Global to Regional Climate and Air Quality Modeling System
A fully coupled global to regional scale model of climate change and air quality has been developed. In this Global-Regional Climate Air Pollution Modeling System (GRE-CAPS), present and future climates are simulated by the Goddard Institute for Space Studies (GISS) General Circulation Model (GCM) version II', which is coupled to a gas-phase and aerosol chemistry model. Meteorology generated by the GCM is downscaled to the regional modeling domain using the Mesoscale Model version 5 regional climate model. The downscaled meteorology is passed on to the regional chemical transport model PMCAMx+. In addition to the downscaled meteorology, the chemical boundary conditions for the regional model are derived from the cells in the global model that correspond to the boundaries of the regional domain, simulating transport into the domain.
The coupled model system is being evaluated for the present day by comparing model-predicted concentrations of O3 and PM2.5 to measured concentrations during the last decade. This comparison between typical present-day measurements and model predictions is made for three modeled present-day Julys (both PM2.5 and O3) and three modeled Januaries (PM2.5). Future concentrations (using the Intergovernmental Panel on Climate Change A2 scenario) are compared to present-day concentrations. Concentrations in specific sites and statistical distributions of concentrations will be examined.
Model-predicted PM2.5 concentrations for a present-day July are shown in Figure 1. This July was rather cool (average T = 19°C), so it is likely that PM2.5 concentrations were lower than in most Julys. Also, it appears that these cool temperatures led to rather low ozone concentrations in this simulated month. This makes the use of ensemble air quality simulations necessary.
Future Activities:
We will continue to proceed along the lines laid out in the original proposal. After completing the two manuscripts under preparation, we will complete development and evaluation of the GRE-CAPS for the present day and submit a paper for publication. After this, we will perform a suite of future change scenarios in GRE-CAPS that show a range of changes in three major categories: anthropogenic emissions, climate-sensitive biogenic emissions, and climate change itself. Finally, we will investigate whether a model simpler than GRE-CAPS can be used to project future air quality while taking account of global changes in emissions and climate.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
Other project views: | All 9 publications | 4 publications in selected types | All 4 journal articles |
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Pinder RW, Adams PJ, Pandis SN, Gilliland AB. Temporally resolved ammonia emission inventories: current estimates, evaluation tools, and measurement needs. Journal of Geophysical Research-Atmospheres 2006;111:D16310, doi:10.1029/2005JD006603. |
R830961 (2005) |
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Racherla PN, Adams PJ. Sensitivity of global tropospheric ozone and fine particulate matter concentrations to climate change. Journal of Geophysical Research-Atmospheres 2006;111:D24103, doi:10.1029/2005JD006939. |
R830961 (2005) |
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Supplemental Keywords:
ambient air, atmosphere, ozone, particulates, visibility, acid deposition, global climate, tropospheric, chemical transport, oxidants, nitrogen oxides, sulfates, organics, modeling, general circulation models, climate models,, RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, particulate matter, Air Quality, Air Pollutants, Chemistry, climate change, Air Pollution Effects, Monitoring/Modeling, Environmental Monitoring, Atmospheric Sciences, Atmosphere, anthropogenic stress, aerosol formation, ambient aerosol, atmospheric particulate matter, atmospheric dispersion models, ecosystem models, environmental measurement, meteorology, climatic influence, emissions monitoring, global change, ozone, air quality models, climate, modeling, climate models, greenhouse gases, airborne aerosols, atmospheric aerosol particles, atmospheric transport, neural networks, environmental stress, regional emissions model, ecological models, climate model, greenhouse gas, aerosols, atmospheric models, Global Climate Change, atmospheric chemistry, ambient air pollutionRelevant Websites:
http://www.ce.cmu.edu/~adams/index.html Exit
http://www.cheme.cmu.edu/who/faculty/pandis.html Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.