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Activity Number:
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18
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Type:
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Topic Contributed
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Date/Time:
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Sunday, August 3, 2008 : 2:00 PM to 3:50 PM
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Sponsor:
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Section on Risk Analysis
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| Abstract - #300699 |
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Title:
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Quantifying Local Creation and Regional Transport Using a Hierarchical Space-Time Model of Ozone as a Function of Observed NOx, a Latent Voc Process, Emissions, and Meteorology
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Author(s):
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Amy J. Nail*+ and John F. Monahan and Jacqueline Hughes-Oliver
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Companies:
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North Carolina State University and North Carolina State University and North Carolina State University
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Address:
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Campus Box 8203, Raleigh, NC, 27695-8203,
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Keywords:
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ozone ; space-time ; VOC ; NOx ; hierarchical ; transport
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Abstract:
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We explore the ability of a space-time model to decompose the 8-hour ozone concentration at a point in space and time into the parts attributable to local emissions and regional transport. We model ozone as created plus transported ozone plus an error term that has a seasonally varying spatial covariance. We express created ozone as a function of the observed NOx concentration, the latent VOC concentration, and temperature. We model transported ozone as a weighted average of the ozone observed at all sites on the previous day, where the weights are a function of wind speed and direction. The latent VOC process model has a mean trend that includes emissions, temperature, a workday indicator, and an error term with a seasonally varying spatial covariance. Using likelihood methods, we fit the model and obtain predictions for comparison with a withheld data set.
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- The address information is for the authors that have a + after their name.
- Authors who are presenting talks have a * after their name.
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