Simulation of continental U.S. air quality
on climatic time scales: projection in future climate
Ho-Chun
Huang
UIUC
Abstract:
Potential global warming could lead to deteriorating air
quality in the future. To study air quality problems, a mesoscale
meteorological model that integrates all available observed data often
is used to mimic the most realistic weather systems in the present
climate. For future regional climate projection, a regional climate
model (RCM) that can integrate the information of GCM simulations for
future climate conditions is used. The projected future air quality
contains a wide range of uncertainty resulting from, for example, the
driving GCM simulations, emission scenarios, and numerical schemes
implemented in the RCM and air quality model (AQM). The National
Centers for Environmental Prediction-Department of Energy (DOE) global
reanalysis data (R2) was used to drive the RCM meteorology for AQM
simulations representing the present climate. The results of model
evaluation show that the regional climate modeling system has skill in
projecting the future air quality in the Northeast, Midwest, and Texas
subdomains. The U.S. DOE Parallel Climate Model (PCM) simulations were
used to drive AQM simulations for the present climate (1996-2000) for
baseline statistics as well as AQM simulations for a future climate
(2048-2052). To obtain the range of uncertainty in future air quality
projection, two RCM cumulus schemes (Grell and Kain-Fritsch) and two
IPCC emission scenarios (A1Fi and B1) were used. The results, using
30km grid resolution data, show that the changes of daily average ozone
concentration from present climate to future climate ranged from
-10.80% in the Northeast subdomain to 14.06% in the Midwest. The
results also indicate significant changes in the Southeast ranging from
-12.42% to 22.58% (using 90km grid resolution data).