Coherent differential absorption lidar measurements of CO2.
A differential absorption lidar has been built to measure CO2 concentration in the atmosphere. The transmitter is a pulsed single-frequency Ho:Tm:YLF laser at a 2.05-microm wavelength. A coherent heterodyne receiver was used to achieve sensitive detection, with the additional capability for wind profiling by a Doppler technique. Signal processing includes an algorithm for power measurement of a heterodyne signal. Results show a precision of the CO2 concentration measurement of 1%-2% 1sigma standard deviation over column lengths ranging from 1.2 to 2.8 km by an average of 1000 pulse pairs. A preliminary assessment of instrument sensitivity was made with an 8-h-long measurement set, along with correlative measurements with an in situ sensor, to determine that a CO2 trend could be detected.
NASA Langley Research Center, Hampton, Virginia 23681-0001, USA. g.j.koch@larc.nasa.gov
Grady J
GJ
Koch
Bruce W
BW
Barnes
Mulugeta
M
Petros
Jeffrey Y
JY
Beyon
Farzin
F
Amzajerdian
Jirong
J
Yu
Richard E
RE
Davis
Syed
S
Ismail
Stephanie
S
Vay
Michael J
MJ
Kavaya
Upendra N
UN
Singh