Guest blogger Katie Bethea chimes in from NASA’s Langley Research Center…
To call it a “bird’s eye view” is, in this case, not an exaggeration. The bumpy video above was captured by a camera mounted to the belly of a plane that was rising, falling, and pirouetting about 1,000 feet above the roadways and suburbs between Washington, D.C. and Baltimore, Maryland.
The July 5 flight was part of a summer-long air quality study known as DISCOVER-AQ, or Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality. The goal is to sharpen the eyesight of Earth-observing satellites so they can better distinguish between pollution high in the atmosphere versus pollution in the surface layer where we live and breathe.
DISCOVER-AQ planes have been flying over roadways, neighborhoods, and woods between the heavily populated areas of Baltimore and Washington to make observations of air quality during “rush hour” and throughout the day. For the campaign, researchers have loaded two NASA research airplanes—the P-3B and the UC-12—with instruments to measure aerosol particles and trace gases relevant to air quality.
The video above was collected to help researchers visually identify the conditions below in sync with what the scientific instruments are seeing. A continuous video stream is recorded throughout the flights of the P-3B aircraft.
“Our video helps the researchers correlate their instruments’ observations with the ground cover, whether it’s traffic, a city, or a forest,” said John Barrick, one of the DISCOVER-AQ investigators. “Surface temperature is often a clue to ground cover, but our video confirms exactly what we’re flying over.”
Roads and city terrain exhibit different temperature signatures than trees, open fields, and water surfaces. Those varying surface temperatures are one of the reasons for the jumpy recording.
Barrick explains that the pilot flew the P-3B at low altitude (about 1,000 feet) and “by hand” rather than auto-pilot. ”Different types of ground cover heat the air at different rates,” said Barrick. “Turbulence occurs when the air above these different surfaces—the boundary layer—mixes. We spend much of the mission flying through the boundary layer, so we get bounced around quite a bit.”
The team also records the video at a lower frequency data rate to reduce the size of the video files for archiving purposes, making the video a bit choppier than typical TV-quality recordings. A typical flight can last eight hours, and the mission is expecting to make at least 14 flights this summer, creating quite a bit of video to store.