Residents in California's San Joaquin Valley will see some unusual air traffic over their region in January and February of 2013 that is designed to some day help improve the air all of us breathe. Two NASA research planes will fly between Bakersfield and Fresno - one as close as 1,000 feet to the ground – to measure air pollution with a number of onboard science instruments.

The planes are part of a five-year, $30 million NASA science study called DISCOVER-AQ, which stands for Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality. Its team of researchers is working to improve the ability of satellites to consistently observe air quality in the lowest part of the atmosphere. If scientists could more effectively observe pollution from space, they would be able to make better air quality forecasts and more accurately determine where pollution is coming from and how emissions vary. That understanding could also help researchers develop successful strategies to reduce pollution.

One of the big challenges for instruments monitoring air quality from space is to distinguish between pollution high in the atmosphere and pollution near the surface where people live. DISCOVER-AQ will make measurements from the aircraft and from ground-based monitoring sites to help scientists better understand how to "see" ground-level pollution from space in the future.

Technicians at NASA's Langley Research Center in Hampton, Va., prepare a B200 aircraft for the DISCOVER-AQ air pollution measurement mission in California. Credit: NASA Langley/Sean Smith

A P-3B turboprop from Wallops Flight Facility in Wallops Island, Va., will fly close to the ground to measure air pollution during the month-long DISCOVER-AQ mission in California's San Joaquin Valley. Credit: NASA Wallops/Patrick Black

"DISCOVER-AQ is collecting data that will prepare us to make better observations from space as well as determine the best mix of observations to have at the surface for when we have a new satellite instrument in orbit," said James Crawford, the mission's principal investigator at NASA's Langley Research Center in Hampton, Va. "NASA is planning to launch that satellite instrument, called TEMPO, in 2017."

Since many countries, including the United States, have large gaps in ground-based networks of air pollution monitors, experts need satellites to provide a more complete geographic perspective on the distribution of pollutants.

A fleet of Earth-observing satellites, called the Afternoon Constellation or "A-train," will pass over the DISCOVER-AQ study area each day in the early afternoon. The satellites' data will give scientists the chance to compare the view from space with that from the ground and aircraft.

"The A-Train satellites have been useful in giving us a broader view of air pollution than we have ever had before," said Kenneth Pickering, DISCOVER-AQ's project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "DISCOVER-AQ will help scientists interpret that data to improve air quality analysis and regional air quality models."

Flights are scheduled to start January 16 and go through mid-February. A four-engine P-3B turboprop plane from the Wallops Flight Facility in Wallops Island, Va., will carry eight science instruments. A two-engine B200 King Air aircraft from NASA Langley will carry two remote sensors. Sampling will focus on agricultural and vehicle traffic areas extending from Bakersfield to Fresno. The flight path passes over six ground measurement sites operated by the California Air Resources Board and the San Joaquin Valley Air Pollution Control District.

"When you are trying to understand a problem you go where the problem is most obvious," said Crawford. "The central valley of California historically stands out as an area where particulate levels often exceed what we consider healthy."

To capture data on the valley's air quality the117-foot-long P-3B will fly low-altitude spiral profiles over the ground stations. These profiles will extend from as high as 15,000 feet down to 1,000 feet from the ground. The flights will sample air along agricultural and traffic corridors at low altitude between ground stations.

The smaller B200 King Air will collect data from as high as 26,000 feet. The plane's instruments will look down at the surface, much like a satellite instrument, and measure particulate and gaseous air pollution. The airplanes will make their temporary home base at NASA's Dryden Aircraft Operations Facility in Palmdale, Calif. In all, a team of as many as 75 people will support the month-long campaign in the air and on the ground.

Also key to this DISCOVER-AQ mission are partnerships with the National Oceanic and Atmospheric Administration (NOAA), the U.S. Environmental Protection Agency (EPA), and University of California branches in Davis, Irvine and Santa Barbara. Other partners in the California campaign include the National Center for Atmospheric Research (NCAR); University of Maryland branches in College Park and Baltimore County; University of California, Berkeley; University of Colorado, Boulder; Pennsylvania State University, State College; University of Innsbruck (Austria); and Millersville University, Millersville, Penn.

The California series of flights is one of four DISCOVER-AQ field studies. The first was conducted over the Baltimore-Washington, D.C. area in July, 2011. Another is set for Houston later this year and the fourth location will be chosen for 2014.

DISCOVER-AQ is an Earth Venture mission, part of the Earth System Science Pathfinder program also managed at NASA Langley for the Earth Science Division of NASA's Science Mission Directorate in Washington.