Eastern US transport climatology during average, high and low ozone days
- Washington Univ., St. Louis, MO (United States). Center for Air Pollution Impact and Trend Analysis
The ozone transport climatology over the eastern US was established by relating high and low ozone concentrations to their respective regional scale transport conditions during five summers (June, July, and August) from 1991--1995. The transport conditions were established by determining regional source impact areas from forward airmass histories for {approximately} 320 sources. Qualitative estimates of airmass transport directions and speeds were then derived from the size and shape of the source impact areas. The transport conditions were established for both locally and regionally high (90th percentile) and low (10th percentile) daily maximum ozone concentrations. The local regions were defined based on a {approximately} 160 km grid over the eastern US and the regional area was the OTAG domain. The locally high ozone days were associated with transport from within the Eastern US. In contrast, locally low ozone days were associated with transport predominantly from outside the Eastern US, e.g. Canada, Atlantic Ocean, and Gulf of Mexico. During the locally high-ozone days dispersion in the Southeast, east Texas to South Carolina and the Central East, eastern Missouri to West Virginia, was typically poor due to stagnating or recirculating air masses. However, the western and northern sections of the domain experienced stronger and more persistent southerly and westerly transport, respectively. Also, along the boarders of the Central East resultant mass transport was from the Central East, indicating this as a common transport pathway for elevated ozone. The high regional ozone days were associated with slow meandering transport over Kentucky, Tennessee, and West Virginia with strong clockwise transport around this region of stagnation. The low regional ozone days had higher speed southwesterly transport from the Gulf of Mexico and northwesterly transport from Canada into the eastern US.
- OSTI ID:
- 362003
- Report Number(s):
- CONF-980632--
- Country of Publication:
- United States
- Language:
- English
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