Implementation of Raman lidar for profiling of atmospheric water vapor and aerosols at the Southern Great Plains Cloud and Radiation Testbed Site

Conference · Sat Apr 01 04:00:00 EST 1995

OSTI ID:83174

Goldsmith, J E.M.; Bisson, S E; Blair, F H ^[1]; Whiteman, D N; Melfi, S H ^[2]; Ferrare, R A ^[3]

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1. Sandia National Labs., Livermore, CA (United States)
2. NASA/Goddard Space Flight Facility, Greenbelt, MD (United States)
3. Hughes STX Corp., Lanham, MD (United States)

There are clearly identified scientific requirements for continuous profiling of atmospheric water vapor at the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site. Research conducted at several laboratories, including our own collaboration in a previous Instrument Development Project for the Atmospheric Radiation Measurement (ARM) Program, has demonstrated the suitability of Raman lidar for providing measurements that are an excellent match to those requirements. We are currently building a rugged Raman lidar system that will reside permanently at the CART site and that is computer-automated to reduce the requirements for operator interaction. In addition to the design goal of profiling water vapor through most of the troposphere during nighttime and through the boundary layer during daytime, the lidar is intended to provide quantitative characterizations of aerosols and clouds, including depolarization measurements for particle phase studies. Raman lidar systems detect selected species by monitoring the wavelength-shifted molecular return produced by Raman scattering from the chosen molecule or molecules. For water-vapor measurements, the nitrogen Raman signal is observed simultaneously with the water-vapor Raman signal; proper ratioing of the signals yields the water-vapor mixing ratio. Similarly, when the backscatter signal at the laser wavelength (which contains contributions from both Rayleigh and aerosol scattering) is also recorded simultaneously, the ratio of the backscatter signal to the nitrogen Raman signal yields a quantitative measurement of the aerosol scattering ratio. A variety of aerosol and cloud parameters can be derived from this measurement. In aerosol-free regions of the atmosphere, temperature profiles can be derived from the density measurements obtained from the nitrogen Raman signal.

• Research Organization: USDOE Office of Energy Research, Washington, DC (United States). Environmental Sciences Div.
• OSTI ID: 83174
• Report Number(s): CONF-940277--; ON: DE95009951
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AEROSOLS
CLOUDS
DEPOLARIZATION
MIXING RATIO
OPTICAL RADAR
PARAMETRIC ANALYSIS
PHASE STUDIES
RAMAN EFFECT
TROPOSPHERE
WATER VAPOR