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Wind profiles in the atmospheric boundary layer are a very important parameter also to study atmospheric exchange processes. The wind field in the atmospheric baundary layeris highly variable in spatial and temporal scales. For a few possible applications a more frequent wind sensing is necessary, i.e. - for airports located in low level jet areas, - for chemical plants to get information of the transport of toxic gases from leakages, - for meteorology in general to improve the weather forecast, - for environment protection purposes like dispersion studies. Only a few techniques can be applied to get the wind field in the boundary layer. Laser Doppler systems are candidates. LIDAR is an acronym for light detection and ranging, it is one of the most powerful instruments for analysing the atmosphere. A lidar consists of a transmitterand a receiver. The transmitter is sending a fairly collimated pulsed or modulated beam of monochromatic laserlight of acertain frequency into the atmosphere where this light is absorbed or scattered by the particles (molecules, water droplets, ice crystals, dust) of the atmosphere. The highly sensitive receiver records light which is reflected by the atmosphere within a certain field of view (FOV) and with or without a certain state of polarisation. The transmitter and the receiver may be mounted atthe same place (then we call the lidar monostatic) or they may be located in different places (then we call the lidar bistatic). Furthermore, the FOV may be directed alongthe sameordifferent direction asthe (FOVofthe)transmitted beam. Very often the FOVs of the transmitter and the receiver are coaxial cones; sometimes the receiver has several FOVs (e.g. a narrow central FOV and a ring shaped outer FOV) thus enabling recording of light of several states of polarisation (e.g. parallel and perpendicular to the direction of polarisation ofthe transmitted beam) simultaneously. Furthermore, some lidars are capable of transmitting and receiving light of 5everalfrequencies almost simultaneously. In addition to that some lidars provide a possibility of scanning the atmosphere. lidars may be ground-based, airborne or space-based. The primary goal of lidarsensing is to acquire meteorologically important parameters of the atmosphere fromthe lidarsignal. To be ableto obtain such parameters, it is necessary to describe the lidar signal physically sufficiently precisely by a mathematical formula and to solve this formula for the interesting parameters. In this report the application for wind detection is the object. This paper summarizes the principle technique, gives the special design parameters and presents test results. The requirements for the system are a compact design and an automatic or half-automatic operation.
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