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Remote Sensing Wind and Wind Shear System

出版	National Oceanic And Atmospheric Administration, Env.res.labor., Wave Propagat.labor. March, 1977
URL	http://books.google.com.hk/books?id=64Q3xwEACAAJ&hl=&source=gbs_api

註釋The prototype development of an acoustic Doppler remote-sensing system to detect low-level wind shear generated by synoptic-scale features such as frontal surfaces is described. The detector system measures the vertical profile of wind by determining the Doppler frequency shift of vertically transmitted acoustic signals that are scattered by small-scale atmospheric inhomogeneities. Following earlier acoustic Doppler tests at Stapleton International Airport in Denver, Colorado, significant improvements have been accomplished on the acoustic transmitter and receiver antennas, and signal processing. A concial horn reflector antenna with a 2-m diameter aperture fed by 12 high-power acoustic drivers through a manifold increased the transmitted power by more than 100%. Substantial improvements have been achieved in received signal-to-noise ratio by developing a narrow-beam, off-focus steered receiver antenna that is capable of tracking the upward propagating acoustic pulse. Development of new system software made all-digital signal processing and computerized system control possible. A brief review of wind-shear types and their detection is followed by a discussion of second-generation wind-shear detection systems employing lidar and microwave radar devices.