A video camera on board NASA’s P-3B aircraft captured this vertigo-inducing view of Baltimore’s suburbs as part of an air pollution-monitoring mission called Discover-AQ. The P3-B, loaded with multiple pollution sensors, has been cruising along major transportation corridors in the Washington-Baltimore metro area and flying spirals over six ground stations throughout July. Meanwhile, a smaller aircraft, a UC-12, has been flying along the same approximate flight path but at higher altitude of about 26,000 feet. View the animation below to see the flight paths of both planes.
The goal of the flights is to help piece together a more accurate view of the vertical distribution of air pollution by looking simultaneously at the same pollution events with ground, aircraft, and satellite instruments. Flights for this summer will wrap up by July 29th. The researchers involved in the project haven’t had time to rigorously analyze the data their instruments have collected and publish findings in peer-reviewed science journals yet, but many have posted raw results from the various instruments on Discover-AQ’s science website.
I paged through many of the daily reports and found quite a number of intriguing nuggets of information. For now, though, I’ll share just one set of images – a comparison of particulate pollution levels on July 1 with levels on July 22nd. The data comes from the High Spectral Resolution Lidar (HSRL), a sensor on the UC-12 that uses a radar-like laser technology called lidar to map the distribution of small particles of pollution. HSRL generates data “slices” that show the vertical distribution of the particles, known generally as aerosols, from ground level up to eight kilometers.
July 1 Flight (minimal particulate air pollution)
July 22nd Flight (heavy particulate air pollution)
In the HSRL data readouts, high levels of aerosols are shown in red and yellow, while lower levels of particles are shown in blue. On the first day of science flights – July 1st – temperatures were moderate and aerosol levels were low. By the tenth flight, the mid-Atlantic was in the midst of a brutal heat wave (which the Star-Ledger weather team want to call Humisery11), and both ozone and particulate counts from ground stations had shot up.
The HSRL slices capture the difference between clear and pollution-laden skies beautifully. The first flight shows just moderate levels of ground-level pollution – the yellow band in the image below that reaches up to about 3 kilometers. In contrast, the flight on the 22nd, a day that temperatures in Baltimore hit 105 °F, shows a deep red swath of particle pollution near the surface.
HSRL data can be a little confusing to make sense of when you first see it, so realize that scientists plot the data out in a horizontal strip with the passage of time on the upper x axis (the numbers with the UT units) and the latitude and longitude on the lower x axis. Altitude is shown on the y-axis. The two images below should help you see how the strips of data relate to the trapezoidal flight paths.
July 1st Flight
July 22nd Flight