ABSTRACT
A high-resolution incoherent Doppler lidar has been constructed at the University of Michigan Space Physics Research Laboratory. The primary purpose of this lidar is to measure vertical profiles of the horizontal wind field with high spatial and temporal resolution. In mid-1994 a rawinsonde system was used to assess the performance of the lidar. The resulting comparisons of profiles from the balloons and the lidar are shown. The comparisons show an ~2-m/s rms error between the two systems. The reasons for this error are discussed, and a sensitivity study is shown to illustrate the sensitivity of the lidar wind measurements to various system parameters. Finally, steps that are being taken to improve the systematic errors are discussed.
ABSTRACT
The University of Michigan has developed an incoherent-detection Doppler lidar system that continuously measures vertical profiles of horizontal winds and aerosol backscatter. An overview of the instrument is given, followed by a description of improvements that have been made to control the system stability. Most notably, an active feedback system has been implemented to improve the laser frequency stability. A detailed forward model of the instrument is developed that includes many subtle effects, such as detector nonlinearity. A nonlinear least-squares inversion method is then described that permits the recovery of Doppler shift and aerosol backscatter without requiring assumptions about the molecular component of the signal. Examples of wind and aerosol backscatter profiles are shown to illustrate the capabilities of the fitting method.
