NASA - National Aeronautics and Space Administration

One thousand flight hours might not sound like a lot of time on an airplane, but for a NASA remote-sensing instrument, it's a milestone.

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The B-200 with HSRL aboard at Yellowknife Airport in Northwest Territories, Canada. This image, captioned "NASA's in Town!" was captured by local photographer Jason Pineau in July 2008, during a mission to study smoke plumes from northern latitude forest fires. Credit: Jason Pineau

More Information:
› HSRL site
› NASA's A-Train

The High Spectral Resolution Lidar (HSRL) has flown 1,023.5 hours to be exact, on the King Air B-200 based at NASA's Langley Research Center in Hampton, Va. Since it was first integrated aboard on Dec. 23 of 2005, the instrument has been winging around the U.S. and beyond, taking atmospheric data.

"The HSRL instrument has operated all over the continental U.S., Alaska, Mexico, Canada and the Caribbean," said Langley scientist Ray Rogers, a member of the HSRL team.

"This is a huge accomplishment for the Science, Research and Technology, and Engineering directorates, which developed, built, operate and maintain the instrument," he said. "This is also a major milestone for the Research Services Directorate as well, because they never had a single science instrument put 1,000 hours on an aircraft."

In all, the desk-size HSRL has participated in about 15 specific deployments, said Rogers.

The 1,000-hour milestone was reached during a flight over the Caribbean on Aug. 24, 2010. The instrument on the B-200 was taking "validation" data for a similar instrument aboard NASA's Earth-orbiting Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite.

CALIPSO is one of several satellites studying the role that clouds and aerosols - particles in the atmosphere - play in regulating the planet's weather, climate and air quality. The HSRL on the King Air has flown 101 of its 332 flights along the CALIPSO track.


Understanding our atmosphere

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Arctic haze in blue as seen through a slice of the atmosphere in spring 2008 with the High Spectral Resolution Lidar instrument on NASA's B-200 aircraft. The flight was part of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission. The haze is composed of tiny atmospheric particles called aerosols, which are transported from mid-latitudes into the Arctic, likely impacting climate and climate feedback mechanisms. Credit: NASA

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Research scientist Ray Rogers with the HSRL on the King Air B-200. Credit: NASA

The instrument typically is used as part of field campaigns involving NASA and other partners. For example, the HSRL was part of an initiative to study air pollution in Mexico City with the National Science Foundation, the Department of Energy, several universities, and more than a dozen Mexican partners. The findings are expected to be applicable to the world's megacities -- those with 10 million or more inhabitants.

It also gathered data in Texas and the Gulf of Mexico as part of a National Oceanic and Atmospheric Administration campaign to provide a better understanding of the sources of ozone and aerosols in the atmosphere and the influence they have on the climate regionally and globally, as well as their impact on human health and regional haze.

In California's San Joaquin Valley, the HSRL was part of a campaign to study air quality in the pollution-prone region in conjunction with the Environmental Protection Agency.


How it Works

The HSRL instrument is an innovative technology called lidar that is similar to radar. With lidar, radio waves are replaced with laser light. Lidar allows researchers to see the vertical dimension of the atmosphere, and the HSRL makes measurements that can distinguish among different aerosol types and their sources. Data acquired with HSRL along the CALIPSO track are used to ensure that the CALIPSO algorithms are producing similar results.

Also currently onboard the B-200 is an instrument from NASA's Goddard Institute for Space Studies in New York, the Research Scanning Polarimeter (RSP). The RSP measures polarized light to get a more accurate reading of the reflective and absorptive properties of aerosols.

RSP uses crystal prisms to filter out the bright glare from Earth's surface, functioning like polarized sunglasses by only allowing light waves oriented in specific directions to pass. This technique provides additional data that could not otherwise be obtained.

The RSP's observations also are complementary to the HSRL, which can be combined to improve the data products better than if only one instrument is used.

The tight-knit HSRL team also includes Chris Hostetler, John Hair, David Harper, Tony Cook and Terry Mack. "They are the architects behind this project," said Michael Obland, another team member and a research scientist at NASA Langley. "I think it is a compelling story that Chris and John started the instrument as a drawing on a napkin and built it from nothing without dedicated funding."

"They had a vision," Obland said, "and cobbled together funding from various sources to create what became the longest-running science instrument on an aircraft at the hangar."

Michael Finneran
NASA Langley Research Center