Atmospheric extinction from Raman lidar and a bi-static remotereceiver

摘要

The scattering of optical radiation in the visible, ultravioletnand infrared regions of the spectrum has a major impact on commercialnair traffic and on many military systems. It has become criticallynimportant, with modern systems, that the electro-optical environment benproperly characterized. Lidar techniques show great promise forndescribing the electro-optical scattering environment. Most of the pastnapplications of lidar have failed to provide satisfactory resultsnbecause the techniques have generally focused on measurements of thenbackscattered radiation at the laser fundamental wavelength. The authorsnhave been able to demonstrate that the rotational and vibrational Ramannbackscatter can be used to determine the extinction profile throughnoptical scattering regions containing aerosols and cloud layers. Theynhave developed a secondary bi-static remote receiver designed to collectnscattering angle and polarization information from a laser remotensensing system. This instrument collects an image of the radiationnscattered from the first few kilometers of the atmospheric path to helpndetermine atmospheric particle size distributions. By collecting data atndifferent angles from the laser transmitter, additional informationncontained in the scattering angle phase function can be obtained. ThenRaman lidar extinction together with the backscatter phase function andnpolarization provide information on the particle size distribution thatnshould allow extension of the extinction and transmission calculationsnto a wider range of wavelengths