Development of a high spatial and temporal resolution Raman lidar for turbulent observations

Water vapor plays an important role in weather, global climate processes and atmospheric chemistry. It is the most significant greenhouse gas and affects the planet's radiative and non-radiative energy balance. The distribution of water vapor in the atmosphere is quite variable both horizontally and vertically and has a significant influence on the atmospheric circulation and temperature structure. Accurate data about water vapor and temperature is needed for weather forecasting, weather and climate research, boundary layer and cloud process studies, and atmospheric chemistry. Despite the need for these data, obtaining accurate water vapor and temperature measurements with high temporal and spatial resolution has remained an only partially solved problem. The Raman lidar technique for water vapor and temperature measurements is a straightforward method and is based on well-known physical principles. It can supply accurate data with high spatial and temporal resolution for weather, climate, atmospheric boundary layer (ABL) studies and other atmospheric research. One of the two goals of this thesis is to develop and construct a Raman lidar instrument with high spatial (1.5 m) and temporal (1 s) resolution and an operational range of 15 – 500 m for systematic observations of water vapor profiles. The measured profiles together with a new generation of Large Eddy Simulations (LES) will be used to attain an improved understanding of the complex linkages between the land surface and the overlying atmospheric boundary layer. The second goal is to develop and test a new method for the determination of the atmospheric transmission correction factor for non solar-blind water vapor Raman lidars based exclusively on the use of Raman lidar signals without needing a priori information about the aerosol optical properties.