Jan Froh (2021) Development of spectral measurement methods for Doppler lidar (PhD Thesis)

For coverage the middle atmosphere (10-100 km) a compact transportable Doppler lidar (≈ 1 m³) with daylight capability was developed in this work. First atmospheric measurements confirm the system performance. With this new system, the Mie scattering (aerosols), Rayleigh scattering (air molecules) and the resonance fluorescence of free potassium atoms are measured over the complete altitude range of the middle atmosphere with high temporal, spatial and spectral resolution. The analysing of the Doppler shift, Doppler broadening and signal strength allows accurate wind, temperature and aerosol measurements. In this work, new spectral methods were developed which examined complete Doppler spectra. A novel tunable alexandrite laser and various optical filters were used. Compared to conventional Doppler lidars, the spectral widths are reduced by several orders of magnitude which results in a high sensitivity for wind, high visibility of aerosols and daylight capability. The system was developed as a network lidar. In future, it will be used as part of VAHCOLI (Vertical And Horizotal Coverage by Lidar) in a network of several such devices for multidimensional measurements of the atmosphere.