| High-resolution remote measurements of vertical wind profiles by lidar (laser radar) are desirable for a number of reasons, including the detection of shear layers in the atmosphere, and scientific studies of turbulence. Existing methods for the determination of wind speed by lidar involve correlations of several separate lidar signals and are plagued with noise problems and complicated data analysis.;A new method of wind measurement is proposed involving the emission of two arrays of beams, along with an elegant new mathematical technique for the analysis of the signals thus produced. In contrast to conventional methods for determination of wind speed with lidar devices, the new method involves relatively simple and cheap hardware, and relatively fast data analysis. The proposed method is tested in simulations, and implemented and tested in a new and unique lidar device. Preliminary measurements obtained with this device demonstrate the capability of the method for producing reasonable results, and a fully reliable instrument operable under a wide range of conditions may be obtained with future refinements.;In addition, the new mathematical method involves the natural logarithm of a ratio of Fourier Transforms, which is designated as the "relative modulation function", and is shown to be useful in the comparison of two signals, particularly in the determination of time or space lags. When applied to multibeam lidar data, it provides a unique function of wind angle and direction. |
