LASE
Points of Contact:
-
Edward V. Browell & Syed Ismail
- NASA Langley Research Center
- M.S. 401A
- Hampton, Virginia 23681
- Office Telephone(s): (757) 864-1273, (757) 864-2719
- FAX: (757) 864 7790
- E-mail: e.v.browell@larc.nasa.gov,
syed.ismail@larc.nasa.gov
- LASE Homepage: http://asd-www.larc.nasa.gov/lase/ASDlase.html
Brief Instrument Description of the
Lidar Atmospheric Sensing Experiment (LASE)
The Lidar Atmospheric Sensing
Experiment (LASE) uses the Differential Absorption Lidar (DIAL) technique
for simultaneous water vapor and aerosol profile measurements over the
entire troposphere. LASE is an autonomous DIAL system that flies on the
NASA ER-2 aircraft. The LASE system operates in the 815-nm wavelength region
and uses a double pulsed Ti:sapphire laser that is locked onto a water
vapor line. The LASE signal processor uses a multi-detector/digitizer system
to preserve signal precision, cover a large signal dynamic range, and to
minimize signal overload recovery effects. The LASE system has undergone
five flight series including an extensive LASE Validation Field Experiment
at NASA Wallops Flight Facility (WFF) during September 1995 and a LASE
flight series in conjunction with the Tropospheric Aerosol Radiative Observational
Experiment (TARFOX) at WFF during July 1996. LASE system has proven to
be capable of measuring water vapor profiles over the entire troposphere
with high accuracy during both day and night background conditions. The
LASE system is also a very sensitive profiler of atmospheric aerosol backscatter
over the 0-18 km altitude region. Current plans are to reconfigure LASE
for operation from NASA DC-8 and P-3 aircraft besides retaining capability
to fly on the ER-2. The capabilities of LASE are listed in Table 1.
References:
Browell, E.V.,
et al., 1996: LASE Validation Experiment and Atmospheric Case Studies 18th
Int. Laser Radar Conf., Abstracts, P-31, July 22-26.
Browell E.V.,
et al., 1994: Differential Absorption Lidar Measurements of Water Vapor,
IGARSS'94, California Inst. Tech., Pasadena, CA, Aug. 8-12.
Ismail, S.,
Browell, E. V., 1993: Recent Developments Towards the Deployment of NASA
LASE Water Vapor System, Conf. Proceeds., CO-MEAS, pp 142-145, March 22-25.
Table 1: LASE WATER VAPOR AND AEROSOL PROFILING
CAPABILITY
(CAMEX MISSIONS ON DC-8 OR ER-2)
Water Vapor:
-
Altitude Coverage*
-
Measurement Capability
-
Measurement Range
-
Accuracy (Mixing Ratio)
-
Resolution
|
-
Ground to tropopause
-
Day and night
-
0.01 G/KG to 20 G/KG
-
Better than 10% (or 0.01 G/KG)
-
10 KM (Horizontal) and 0.3 KM (Vertical)
|
Aerosol Backscatter (815 -NM):
-
Altitude Coverage*
-
Measurement Capability
-
Measurement Range
-
Precision
-
Resolution
|
-
Ground to lower stratosphere
-
Day and night
-
0.2 to >100 (Aerosol scattering ratios (S/R))
-
Better than 3% (or 0.2 S/R)
-
0.2 KM (Horizontal) and 0.3 KM (Vertical)
|
*Water vapor and aerosol measurements with the exception
of a region within +/- 1 KM aircraft altitude due to near field signal
overlap/saturation considerations.
|