Discover-AQ: Targeted Airborne and Ground-Based Observations of Near-Surface Pollution

The project is called DISCOVER-AQ, which stands for Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality. Discover - AQ is a four-year campaign to improve the use of satellites to monitor air quality for public health and environmental benefit. The fundamental challenge for satellites measuring air quality is to distinguish between pollution near the surface and pollution higher in the atmosphere. Scientific questions remain about the vertical distribution of pollutants. How far up in the atmosphere are morning and evening spikes in pollution associated with rush hour noticeable? How does ozone, which peaks near the surface in afternoon, behave at other altitudes throughout the day? When is the best time of the day for satellites to measure various pollutants?

Measurements from aircraft, in combination with ground-based measurements, offer a key perspective that makes such distinctions easier to make. The problem is particularly pronounced for pollutants that are abundant at the surface and higher in the atmosphere. For example, a "Code Red" air-quality day during the summer might produce very high concentrations of ozone in the bottom few kilometers of the atmosphere, yet generate a change of a mere 1 or 2 percent to a total column of ozone. Studies suggest that discrepancies of as much as 30 to 50 percent exist between estimates of ground nitrogen dioxide inferred from the Ozone Monitoring Instrument(OMI), an instrument on NASA's Aura satellite launched in 2004, and measurements from ground-based instruments. DISCOVER-AQ will address such problems by helping researchers develop a three-dimensional view of how air pollutants are distributed and move between different levels of the atmosphere throughout the day.

A phalanx of ground-based instruments will offer a critical view of the same patches of air the aircraft are monitoring from above. While NASA sponsors certain ground instruments, other institutions including the Environmental Protection Agency, the Maryland Department of the Environment, Howard University, and Pennsylvania State University manage the instruments at the ground stations.

Scientists will use information collected during the DISCOVER-AQ campaign to improve measurements from existing satellites and to help establish parameters for future NASA satellite missions that will monitor air quality. More information is available at http://www.nasa.gov/mission_pages/discover-aq/index.html.