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Measurement of range-resolved water vapor concentration by coherent CO2 differential absorption lidar
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1984
[PDF-393.99 MB]
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Description:The feasibility of measuring differential absorption lidar (DIAL) species concentrations with a coherent CO^ lidar is examined. A computer simulation estimated errors in coherent and incoherent C02 DIAL measurements due to speckle, noise, turbulence, and atmospheric inhomogeneities. Results indicate that direct-detection is the preferable mode at shorter ranges while heterodyne detection provides better sensitivity beyond a few kilometers. The NOAA pulsed lidar was used to investigate statistical properties of the aerosol backscattered returns that are processed to obtain DIAL measurements. Fluctuations due to speckle and noise necessitate averaging of returns from multiple pulses for accurate concentration estimate. Other atmospheric effects can be minimized by judicious signal processing. The first rangeresolved coherent DIAL water vapor measurements were made with the lidar to ranges beyond 10 km. Estimates compared reasonably with those from rawinsondes, although some tendency to overestimate relative to the sondes was observed. Wind velocity profiles were also obtained, demonstrating the feasibility of simultaneous concentration and wind velocity measurements.
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Rights Information:CC0 Public Domain
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