Combining in situ and Remote Measurements with Models: Picking the Right Tools
Abstract
Visibility reduction, photochemical smog, and the global climate changes these pollutants engender involve complex interactions of emissions, atmospheric transformations, and transport. In situ measurements, numerical simulations, and remotely sensed data all have strengths and weaknesses, but picking the right combination of tools can avoid the limitations of any one method to advance the science and provide policy-relevant research on the causes and nature of air pollution. The Regional Atmospheric Measurement, Modeling, and Prediction Program (RAMMPP) seeks a balanced approach to air pollution studies in the Mid Atlantic. We employ surface and airborne measurements as input and tests for air quality models of the Baltimore/Washington area. Both ozone and summertime haze tend to form in blobs covering areas hundreds of km on a side and lasting several days. Point and aircraft measurements offer high accuracy, but cannot always characterize the spatial and temporal extent of these masses. To provide the big picture, we are exploring the use of satellite data including GOME and SCIAMACHY for SO2, TOMS for tropospheric O3, and MODIS for aerosol optical depth. Comparison with direct measurements can greatly improve retrievals of atmospheric composition. For example, GOME identified a persistent hot spot in SO2 over eastern North America where many large, coal-fired power plants are located. Aircraft measurements confirmed the presence of this hotspot, but indicated an average column content of 0.65 DU (m atm cm), while the satellite instrument, indicated only 0.14 DU. GOME uses, however, an initial guess for the altitudinal distribution of the SO2, and when the retrieval algorithm is corrected with the observed profile, the result is 0.42 DU. Further improving the retrieval with more representative background values yields a mean SO2 column content of 0.52 DU, within experimental uncertainty of the aircraft value. Ozone and aerosol retrievals can be similarly customized and compared to the output of a chemical transport model such as CMAQ.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2004
- Bibcode:
- 2004AGUSM.A31D..02D
- Keywords:
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- 0345 Pollution: urban and regional (0305);
- 0368 Troposphere: constituent transport and chemistry;
- 1640 Remote sensing