Fast scanning lidar system can provide aerosol volume distribution and time evolution in atmosphere. Usually fast scanning lidar has a relative simple configuration. Multi-wavelength depolarization and Raman measurements gave us more information about the particulate shape, type and dimension. The most Raman lidars use high power laser source in order to get enough Raman scattering signal. One of a challenge for Raman lidar system is to have enough dynamic range to satisfy the measurements both for pure molecule Rayleigh scattering and high dene aerosol, such as dust storm, volcano emitted aerosol and high polluted urban aerosol. The estimation of microphysical properties requires independent measurements of both backscatter and extinction coefficient at several wavelengths (multi-wavelength Raman lidar). Additional information can be retrieved from simultaneous measurements of the depolarization signal and water vapor mixing ratio, since those measurements are particularly useful to correlate aerosol optical properties with their shape and hygroscopicity. A new, versatile prototype of polarization, Raman scanning lidar system (named AMPLE - Aerosol Multi-wavelength Polarization LIDAR Experiment) has been designed and implemented at Napoli Research Unit of CNISM. AMPLE is a project of the scientific co-operation between CNISM and the Beijing Research Institute of Telemetry (BRIT) and represents the first action of the recently founded Italy-China Laser Remote Sensing Joint Research Center. The AMPLE system has been designed to perform volume scanning of the atmosphere and to retrieve high quality 3D map of particlulate optical properties and their time evolution. The AMPLE system is equipped with a doubled and tripled Nd:YAG diode-pumped laser that is specifically designed for this device, with a repetition rate of 1KHz and average optical power of 0.6W at 355nm, 1.5W at 532nm and 1W at 1064nm. The relative high repetition rate laser source can increase the detectable signal dynamic range. Each detected signal is acquired by multi-channel scalers with a raw spatial resolution varying from 30cm to 30m. Moreover, polarization purity of laser line allows to perform polarization measurements at both 355 and 532nm. This device is installed in the Beijing city area, which is strongly affected from anthropogenic pollution and sand dust from Gobi desert. A second unit of AMPLE has been realized for the National Institute for Geophysics and Volcanology (section of Catania) to be installed on the slope of Mt. Etna. This second system is configured as polarized scanning lidar. It will allow to monitor the ash emission during Mt. Etna explosive activity so that the plume mapping and the estimated particulate mass concentrations will be retrieved.
Implementation of high dynamic Raman lidar system for 3D map of particulate optical properties and their time evolution
Xuan Wang;Antonella Boselli;
2013
Abstract
Fast scanning lidar system can provide aerosol volume distribution and time evolution in atmosphere. Usually fast scanning lidar has a relative simple configuration. Multi-wavelength depolarization and Raman measurements gave us more information about the particulate shape, type and dimension. The most Raman lidars use high power laser source in order to get enough Raman scattering signal. One of a challenge for Raman lidar system is to have enough dynamic range to satisfy the measurements both for pure molecule Rayleigh scattering and high dene aerosol, such as dust storm, volcano emitted aerosol and high polluted urban aerosol. The estimation of microphysical properties requires independent measurements of both backscatter and extinction coefficient at several wavelengths (multi-wavelength Raman lidar). Additional information can be retrieved from simultaneous measurements of the depolarization signal and water vapor mixing ratio, since those measurements are particularly useful to correlate aerosol optical properties with their shape and hygroscopicity. A new, versatile prototype of polarization, Raman scanning lidar system (named AMPLE - Aerosol Multi-wavelength Polarization LIDAR Experiment) has been designed and implemented at Napoli Research Unit of CNISM. AMPLE is a project of the scientific co-operation between CNISM and the Beijing Research Institute of Telemetry (BRIT) and represents the first action of the recently founded Italy-China Laser Remote Sensing Joint Research Center. The AMPLE system has been designed to perform volume scanning of the atmosphere and to retrieve high quality 3D map of particlulate optical properties and their time evolution. The AMPLE system is equipped with a doubled and tripled Nd:YAG diode-pumped laser that is specifically designed for this device, with a repetition rate of 1KHz and average optical power of 0.6W at 355nm, 1.5W at 532nm and 1W at 1064nm. The relative high repetition rate laser source can increase the detectable signal dynamic range. Each detected signal is acquired by multi-channel scalers with a raw spatial resolution varying from 30cm to 30m. Moreover, polarization purity of laser line allows to perform polarization measurements at both 355 and 532nm. This device is installed in the Beijing city area, which is strongly affected from anthropogenic pollution and sand dust from Gobi desert. A second unit of AMPLE has been realized for the National Institute for Geophysics and Volcanology (section of Catania) to be installed on the slope of Mt. Etna. This second system is configured as polarized scanning lidar. It will allow to monitor the ash emission during Mt. Etna explosive activity so that the plume mapping and the estimated particulate mass concentrations will be retrieved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
