Characterization of the ozone and transport conditions during the four OTAG episodes
- Washington Univ., St. Louis, MO (United States). Center for Air Pollution Impact and Trend Analysis
As part of the Ozone Transport Assessment Group (OTAG) activity, four multi-day episodes were selected in July of 1988, 1991, 1993, and 1995 for the simulation of tropospheric ozone. In this analysis these four OTAG episodes were characterized by establishing a qualitative relationships between measured ozone concentrations and associated synoptic scale meteorological and transport conditions over the Eastern US. The analysis of the meteorological and transport data could only be conducted for the 1991, 1993, and 1995 episodes, since data were not available for the 1988 episode. It was found that each episode had persistently elevated ozone concentrations, >100 ppb, over one or more multi-state regions. The 1988 and 1991 episodes were more northerly episodes with elevated ozone concentrations from Illinois to Maine while the 1993 episode had elevated concentrations primarily in the Southeast from eastern Alabama to North Carolina. The 1995 episode had the most wide spread regional ozone with elevated concentrations occurring over broad regions from Texas to Connecticut. Taking the four episodes together, persistently high ozone occurred most frequently over the Midwest and along the Eastern Seaboard. The southwestern part of the domain had the lowest occurrence of high ozone with elevate ozone consistently present only during the 1995 episode. Analysis of the meteorological and transport data showed that during the 1991 and 1995 episodes several days of airmass stagnation occurred in the Midwest which was associated with increased ozone, > 100 ppb, and temperatures. This was followed by strong flow to the east where the elevated Midwest ozone decreased, but the ozone concentration along the Eastern Seaboard remained high or increased. In the Southern part of the domain, Texas to South Carolina elevated ozone concentrations were associated with high temperatures and slow meandering transport.
- OSTI ID:
- 361980
- Report Number(s):
- CONF-980632--
- Country of Publication:
- United States
- Language:
- English
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