Our atmosphere is a complex system in which numerous processes occur on various spatial and temporal scales, connecting the different layers of the atmosphere. To explore this system, the VAHCOLI (Vertical And Horizontal COverage by LIdar) concept was developed at the Leibniz Institute of Atmospheric Physics (IAP), aiming for high-resolution detection of vertical, horizontal, and temporal scales using a lidar array.
Part of this concept are compact, transportable Doppler lidars (approx. 1 m^3) with daylight capability and multiple fields of view (MFOV). This dissertation describes the development and application of the necessary extension for simultaneous measurement of wind, temperature, and aerosols in five fields of view.
A major focus of the work is on the technical development of the extension, the theoretical considerations underlying the design, and the necessary modifications to the existing lidar. The technical development of the MFOV upgrade, including the optimization of the telescope design, the beam switching mechanisms, and the integration of advanced temperature management systems for the lidar telescope optics, is comprehensively described.
Another focus is on the evaluation of measurements with the extended system, conducted during several measurement campaigns between December 2022 and April 2023 at the IAP (54°07'N; 11°46'O). Various new methods were developed to process the raw data into wind, temperatures, and aerosol parameters. The results of the measurement campaigns demonstrate the performance of the extended system. Winds in the five fields of view were measured at heights of up to 25 km solely by aerosol backscattering. The observation of a meridional wind gradient by comparing two opposing fields of view demonstrates the system's ability to capture horizontal scales. The backscatter ratio and backscatter coefficient of aerosols were determined and then used to calculate temperatures in aerosol-influenced atmospheric layers. The lidar measured winds were compared with the data from the European Centre for Medium-Range Weather Forecasts (ECMWF) and measurements of the satellite lidar Aeolus. For a comparison of the backscatter coefficients, results from the WACCM-CARMA model were used, and the temperatures were compared with ECMWF temperatures and lidar measurements of another IAP lidar. Good matches underline the effectiveness of the developed processing methods.
New in the results of this work is the measurement in the middle atmosphere using five fields of view, the development of new processing methods, the determination of 3D winds between 3 and 25 km solely by aerosol backscattering, the high sensitivity of the aerosol measurements, and the determination of accurate temperatures using Rayleigh integration in the presence of aerosols. These results demonstrate the capabilities of the lidar with MFOV extension, and will be used in future measurement campaigns, for example, to validate new spaceborne lidars.