2009 Annual Report - NASA Airborne Science Program

CO2 Laser Sounder
During October 2008 Goddard’s CO2 Laser Sounder
Team successfully demonstrated its new-pulsed
airborne lidar to measure CO2 absorption. The
instrument was configured to fly on the NASA
Glenn Research Center’s Lear 25 aircraft. The lidar
measures the optical absorption due to atmospheric
CO2 in the nadir column from the aircraft to the
surface. The lidar uses a pulsed fiber laser whose
wavelength is scanned across the CO2 line, a 20 cm
diameter receiver telescope, and time and height
resolved photon counting detector and signal
processing.
Initial measurements were demonstrated with the
lidar scanning a CO2 line absorption near 1571 nm
while flying in the vicinity of Cleveland OH. Laser
backscatter and absorption measurements were
over a variety of land surface types, including water
surfaces and through thin clouds, broken clouds and
to cloud tops. Strong laser signals were observed at
altitudes from 2.5 to 11 km on two flights.
The team completed three additional airborne flight
tests during December 2008. During these the team
flew its CO2 Sounder lidar on the NASA-Glenn
Lear-25 and gathered over 6 hours of atmospheric
CO2 column line shape and depth measurements.
Airborne CO2 line shape measurements were made
over Ohio on several flights while flying from 3-11
km altitudes. Subsequently the team deployed to
Ponca City, OK, just east of the DOE ARM site.
There it made 2 flights with 4 hours of airborne
Figure 39:
Aircraft at ARM site.
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