Grantee Research Project Results
2009 Progress Report: Study the Impact of Global Change on Air Quality Using the Global-Through-Urban Weather Research and Forecast Model with Chemistry
EPA Grant Number: R833376Title: Study the Impact of Global Change on Air Quality Using the Global-Through-Urban Weather Research and Forecast Model with Chemistry
Investigators: Zhang, Yang , Streets, David G. , Karamchandani, Prakash
Institution: North Carolina State University , Atmospheric and Environmental Research, Inc. , Argonne National Laboratory
Current Institution: North Carolina State University , Argonne National Laboratory , Atmospheric and Environmental Research, Inc.
EPA Project Officer: Chung, Serena
Project Period: May 7, 2007 through May 6, 2011 (Extended to May 6, 2012)
Project Period Covered by this Report: May 7, 2009 through August 1,2010
Project Amount: $900,000
RFA: Consequences of Global Change For Air Quality (2006) RFA Text | Recipients Lists
Research Category: Climate Change , Air
Objective:
The objectives of this project are to estimate the long-term impacts of global changes on urban and regional air quality over the next 50 years and provide a realistic assessment of those impacts and associated uncertainties using an advanced 3-D model and available observational datasets. We hypothesize that the two-way feedbacks between climate changes and air quality are important in quantifying the impact of global changes on air quality.
Progress Summary:
During this project period, we have accomplished several tasks in model development and applications that are critical to achieve our goals. We updated our emissions, finalized CB05_GE gas-phase chemical mechanism, and improved several aspects of MADRID aerosol module (e.g., nucleation parameterizations) and its interface with the photolysis scheme. We applied GU-WRF/Chem to 5 global-through-urban nested domains and conducted 3-D test simulations for Jan. and Jul., 2001. A comprehensive model evaluation has been conducted with both satellite and ground-base measurements. We also applied GU-WRF/Chem for future year simulations and conducted test simulations for Jan. and Jul., 2050 and their comparisons with NCAR’s CCSM.
Our major findings and their significances are summarized below.
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CB05_GE) is tested for a range of atmospheric conditions using a box-model. Simulations of Arctic conditions, upper tropospheric conditions and lower stratospheric conditions with the box model illustrate the importance of halogen chemistry and heterogeneous reactions (on aerosol surfaces as well as polar stratospheric clouds (PSCs) for stratospheric conditions) for predicting O3 and elemental mercury depletion events that are often observed during these conditions. Depletions that are comparable to observed depletions are predicted under very clean conditions (extremely low or zero concentrations of aldehydes and other VOCs) because these conditions result in less conversion of active chlorine and bromine to more stable products, such as HCl and HBr.
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Different gas-phase mechanisms may lead to different predictions of gases, aerosols, and corresponding aerosol direct and indirect effects. Differences in chemical concentrations caused by different gas-phase mechanisms affect meteorological variables largely through aerosol indirect effect rather than aerosol direct effect. As one of the most recent gas-phase mechanisms, CB05 coupled with WRF/Chem-MADRID has potentials in application to real-time air quality forecasting and extension to global scale modeling.
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GU-WRF/Chem has been developed to provide a unified model framework for air quality and climate simulations with consistent boundary conditions and physical/chemical mechanisms for nested regional/urban applications. Model evaluation for GU-WRF/Chem current-year predictions shows reasonably good agreement with near-surface temperature, water vapors, and shortwave radiation from either reanalysis or satellite dataset, but larger bias in precipitation. It also shows a very good agreement with observed surface O3 and PM2.5 concentrations and reasonably good column CO and NO2 abundances, TOR, and AOD, as well as some cloud-related properties such as cloud fractions and CCN. These results illustrate an overall good model skill of GU-WRF/Chem in reproducing observations.
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Large uncertainties exist in current nucleation parameterizations used in 3-D modeling. Simulated aerosol number concentrations and aerosol indirect effects in terms of CCN and cloud droplet number concentrations are quite sensitive to different nucleation parameterizations used in GU-WRF/Chem.
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GU-WRF/Chem results show that aerosols can have various direct, semi-direct, and indirect effects on PBL meteorology and cloud/precipitation formation. For example, our preliminary results show that aerosols decrease shortwave radiation by up to -45% (global mean: -10%), NO2 photolysis rate by up to -52% (global mean: -11%), near-surface temperature by up to -546% (global mean: -1.6%), PBL height by up to -39% (global mean: -1.7%), and decrease precipitation by up to -82% (global mean: -5%). They can increase CCN by up to 3340% (global mean: 478%) and CDNC by up to 5751% (global mean: 318%). These results will have important implications to the air quality-climate change interactions under current and future climate/emission scenarios. Observations are needed to verify simulated feedbacks, improve models, and reduce the uncertainties in simulated aerosol direct and indirect effects.
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Initial application of GU-WRF/Chem for future year simulations and comparison with CCSM results show that GU-WRF/Chem has a promising skill in simulating future climate and air quality.
Future Activities:
We will complete the implementation of the plume-in-grid treatments into GUWRF/ Chem and conduct simulations over the U.S. domain to evaluate the impact of a more accurate plume treatment on simulated air quality and aerosol direct and indirect effects. We will complete model application and evaluation for 2001 and future-year simulations under future climate/emission scenarios. In addition, we will continue to disseminate our research results at national/international conferences/workshops and prepare manuscripts for publications in peer-reviewed journals.Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 124 publications | 22 publications in selected types | All 20 journal articles |
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Type | Citation | ||
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Zhang Y, Wen X-Y, Jang CJ. Simulating chemistry–aerosol–cloud–radiation–climate feedbacks over the continental U.S. using the online-coupled Weather Research Forecasting Model with Chemistry (WRF/Chem). Atmospheric Environment 2010;44(29):3568-3582. |
R833376 (2009) R833376 (2010) R833376 (Final) |
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Supplemental Keywords:
global-through-urban WRF/Chem, air quality modeling, climate modeling, coupled meteorology and air quality, aerosols, air quality-climate change feedbacks.
, RFA, Air, climate change, Air Pollution Effects, Atmosphere, air quality modeling
Relevant Websites:
The research and resulted publications are disseminated via the web site of Zhang’s group at http://www.meas.ncsu.edu/aqforecasting/
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.