Wind Observation And Development And Designation Of Vehicle-mounted Wind Lidar Of Near Space

Nowadays, the geospace environment is rarely understood due to lacking powerful observations of wind, temperature, density, and pressure. Among all these atmospheric parameters, wind is the most primary one which enables us to go deep into the atmospheric dynamics and environment change prediction. Unfortunately, wind measurements are quite limited by both the global and the local atmospheric monitoring systems, which have severely prevented us from gaining insight into the upper atmosphere. Doppler lidar is thought to be the only candidate to realize measurement of wind field in global scale with sufficiently high resolution and precision. Direct detection lidar based on double edge technique with a Fabry-Perot interferometer as frequency discriminator is widely used and is capable to cover wind measurement from ground to mesosphere.In this work, we present detailed discussion about design and development of a near space wind lidar system in chapter 3, including its design principle, laser transmitter, and solutions of laser frequency drift. We optimized the whole optical path from laser transmitter to lidar receiver. In order to match the post fiber optics, a FPI with large aperture is designed, together with a serve loop circuit to actively lock the stretched laser pulse to the locking channel of the FPI. The pulse is stretched as we use a integrate sphere before it coupled into the multimode fiber. A benefit is that the light incident into the FPI generate uniform illumination, as a result, more accurate frequency locking is realized. All these effort do help to establish a more stable and precise optical receiver subsystem.In chapter 4, an advanced wind retrieval algorithm is introduced. The FPI transmission curve is calibrated and then compared with a theoretical one, which shows good agreement between them. We also proposed an experimental setup to measure the laser spectrum, which is then used to estimate the Rayleigh-Brillouin spectrum.In chapter 5, a large set of wind data is analyzed. The vertical features of wind field between upper troposphere and lower stratosphere over Xinjiang region, as well as the whole picture of vertical wind over Jiuquan are given. We also showed case study of gravity waves by using wind data. Several key parameters of gravity waves over Jiuquan are displayed.