Topic：Development of High-Spectral-Resolution Lidar for Profiling Optical Properties of Atmosphere Aerosols
Speaker: Prof. Liu Dong (Zhejiang University)
Date: May 23 at 19:00-21:00
Venue：B707, New Main Building
Abstract：
Quantitative measurements of atmospheric aerosol optical and micro-physical properties are required for studies of the Earth’s radiation budget and climate change. Backscatter lidars are widely used to measure atmospheric aerosols and lots of great results have been obtained. However, there are still some critical problems left preventing backscatter lidars from getting accurate optical and micro-physical properties of atmospheric aerosols. To begin with, in the data processing of standard backscatter lidars, the extinction-to-backscatter ratio (or the lidar ratio) has to be assumed to be a constant and known in order to solve the ‘one-equation, two-unknown’ problem to retrieve aerosol optical properties. The retrieval accuracy of backscatter lidars is therefore limited by the accuracy of lidar ratio selection. Taking advantage of the broad spectrum of the Cabannes-Brillouin scattering from atmospheric molecules, the high spectral resolution lidar (HSRL) technique employs a narrow spectral filter to reject the aerosol Mie scattering component in the lidar return signals. Therefore, an HSRL can directly measure the extinction and backscatter coefficient as well as the lidar ratio.
Biography of the Speaker：
Liu Dong is a professor and PhD supervisor of Zhejiang University. He received his Bachelor’s and PhD degrees from the Department of Optical Science and Engineering (now known as the College of Optical Science and Engineering) of Zhejiang University in 2005 and 2010 respectively. From 2010 to 2012, he worked as a postdoctoral researcher at the National Aeronautics and Space Administration (NASA). Since September 2012, he has been teaching and conducting research into optoelectronic detection and remote sensing at Zhejiang University. At present, he is a deputy director of State Key Laboratory of Modern Optical Instrumentation, Assistant Dean of the College of Optical Science and Engineering and a member of the Special Committee of Optical Testing and the Special Committee of Environmental Optics of the Chinese Optical Society.
He has led one national key research and development project (youth), three projects supported by the National Natural Science Foundation of China, and over ten national, provincial or ministry-level projects. He also published more than 30 papers in journals indexed by SCI and nearly 100 indexed by Ei Compendex, and applied for/obtained over 30 national patents.
In recent years, Prof. Liu’s research focuses on atmospheric aerosol lidar and high-spectral-resolution lidar (HSRL). He put forward the idea of using field-widened Michelson Interferometeras spectral discriminator, which is free from the restrictions of operating wavelength and field angle of classical HSRL spectral discriminators, offering an effective method to develop multi-wavelength HSRL. He also adopted an off-axis reflective optical transceiver system that has no non-detection zone and achieved simultaneous measurement of atmosphere aerosol and state parameters like atmospheric temperature by a two-channel spectral discriminator, which, unlike the normal aerosol remoter sensing HSRL that relies on the input of atmospheric parameters, can accurately detect the optical properties of atmospheric aerosol.
School of Instrumentation Science and Opto-electronics Engineering
