OMI Satellite Data AnalysisWeekly, Seasonal, Elevation Pattern of NO2

M. Kieffer, S. Kovacs, E. RobinsonAdvisor: R. B. Husar

Washington University, St. Louis, June-July 2007

This is a preliminary analysis of the OMI NO2 dataset.

The OMI instrument retrieves the global, daily, vertical column concentration of NO2 in the atmosphere at the spatial resolution of about 30 km. On individual days the NO2 pattern is patchy, however aggregation over long periods of time permits the extraction of interesting

pattern that provide a unique contribution to air quality analysis.

Weekly Pattern of Columnar NO2

• In the first example, we will look at the NO2 concentration over the continental U.S. as averaged over each day of the week, since 2004. The resulting weekly pattern is explicitly due to human activities since none of the natural phenomena depend on week day.

• The weekly cycle clearly shows a build up of NO2 from Monday till Friday and the remarkable drop on Sundays. This is particularly evident over the North Eastern Megalopolis which is dominated by NOx emissions from automobiles

• This information should be helpful for improving the existing emission inventories.

Seasonal Pattern of Columnar NO2

• The seasonal pattern of NO2 is also significant and can be used for emission inventory validation. However, the interpretation of the seasonal cycle is more complicated.

Elevation Pattern of NO2

• The spatial pattern of NO2 shows a “hole” over the Appalachian Mountains.

• A view of NO2 on the 3-dimensional map of Google Earth shows clearly that the NO2 hole simply represents the fact that the NO2 is confined to the low lying surface layers and that the high elevation mountain peaks are outside the dirty layer where NO2 resides.

Links

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