U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights


Using Regional Air Quality Networks to Evaluate Global Chemistry-Climate Modeling of Surface Ozone
Published: September 25, 2015
Posted: May 23, 2016

Chemistry-climate models provide a valuable means for projecting future air quality in a changing climate, but recent assessments have lacked commensurate observational comparisons to establish their credibility in reproducing current cycles in surface ozone over polluted regions. The models in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) were used in the recent assessment of the Intergovernmental Panel on Climate Change (IPCC) and represent the most advanced attempt to simulate global surface ozone in a future climate. However, to have confidence in the models’ projections, their ability to simulate the observed, present-day surface ozone climatology must be evaluated.

A recent study tested the current generation of global chemistry-climate models in their ability to simulate observed, present-day surface ozone. Models are evaluated against hourly surface ozone from 4,217 stations in North America and Europe that are averaged over 1° x 1° grid cells, allowing commensurate model-measurement comparison. Models are generally biased high during all hours of the day and in all regions. Most models simulate the shape of regional summertime diurnal and annual cycles well, correctly matching the timing of hourly (~15:00) and monthly (mid-June) peak surface ozone abundance. The amplitude of these cycles is less successfully matched. The observed summertime diurnal range (~25 parts per billion (ppb)) is underestimated in all regions by about 7 ppb, and the observed seasonal range (~21 ppb) is underestimated by about 5 ppb except in the most polluted regions where it is overestimated by about 5 ppb. The models generally match the pattern of the observed summertime ozone enhancement, but they overestimate its magnitude in most regions. Most models capture the observed distribution of extreme episode sizes, correctly showing that about 80 percent of individual extreme events occur in large-scale, multi-day episodes of more than 100 grid cells. The models also match the observed linear relationship between episode size and a measure of episode intensity, which shows increases in ozone abundance by up to 6 ppb for larger-sized episodes. This study concludes that the skill of the models evaluated provides confidence in their projections of future surface ozone.

Reference: Schnell, J. L., M. J. Prather, B. Josse, V. Naik, L. W. Horowitz, P. Cameron-Smith, D. Bergmann, G. Zeng, D. A. Plummer, K. Sudo, T. Nagashima, D. T. Shindell, G. Faluvegi, and S. A. Strode. 2015. “Use of North American and European Air Quality Networks to Evaluate Global Chemistry–Climate Modeling of Surface Ozone,” Atmospheric Chemistry and Physics 15, 10581–96. DOI: 10.5194/acp-15-10581-2015. (Reference link)

Contact: Dorothy Koch, SC-23.1, (301) 903-0105
Topic Areas:

  • Research Area: Earth and Environmental Systems Modeling

Division: SC-23.1 Climate and Environmental Sciences Division, BER

 

BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

May 10, 2019
Quantifying Decision Uncertainty in Water Management via a Coupled Agent-Based Model
Considering risk perception can improve the representation of human decision-making processes in age [more...]

May 09, 2019
Projecting Global Urban Area Growth Through 2100 Based on Historical Time Series Data and Future Scenarios
Study provides country-specific urban area growth models and the first dataset on country-level urba [more...]

May 05, 2019
Calibrating Building Energy Demand Models to Refine Long-Term Energy Planning
A new, flexible calibration approach improved model accuracy in capturing year-to-year changes in bu [more...]

May 03, 2019
Calibration and Uncertainty Analysis of Demeter for Better Downscaling of Global Land Use and Land Cover Projections
Researchers improved the Demeter model’s performance by calibrating key parameters and establi [more...]

Apr 22, 2019
Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles
Representation of warm temperature events varies considerably among global climate models, which has [more...]

List all highlights (possible long download time)