生物战剂气溶胶激光雷达遥测技术研究

Study on bio-agents/bioaerosols remote sensing technology by lidar

基于激光诱导荧光(LIF)原理和弹性散射作用于非球形粒子上形成的偏振特性,设计并研制由3个激光波长、2个接收望远镜、退偏组件和荧光光谱仪等组成的生物战剂/气溶胶Mie散射、荧光和偏振激光雷达。退偏比的水平测量结果表明:1)退偏比表现出较强的波长依赖性;2)多波长退偏比测量可以显著提高生物战剂的鉴别能力。退偏比的垂直测量结果表明:气溶胶在边界层内总体上维持在较低的水平,在温湿压风等气象条件和光生化条件的作用下,对流层底层空变化明显,在部分云团处,退偏振比可达0.3;气溶胶的Mie散射时空分布表明,355nm波长的测云能力在激光出射能量相当时较532nm强。

Based on two physical phenomena,laser induced fluorescence(LIF)and depolarization,resulting from elastic scattering on non-spherical particles,a compact lidar system for real-time standoff detection of bio-agents/bioaerosol is developed.The system includes three laser sources,two receiving telescopes,depolarization component and spectral signature analyzing spectrograph.For the horizontal polarization measurements,it can be concluded that,1)the depolarization ratios are wavelength-dependent;2)the discrimination efficiency increases significantly with the number of wavelengths used.And from the depolarization time-space distributions results,it can be revealed that,the aerosol depolarization ratio remains at a low level within the boundary layer,and can be affected by the wind,humidity,temperature and other meteorological factors,the complex zigzag vertical distributions of depolarization ratio is obvious in the tropospheric layer,the depolarization can reach 0.3at some clouds.Finally,the Mie scattering observation results with the 532 nm and 355 nm wavelengths show that the more complicated layered structure of aerosol time-space distribution can be obtained with the 355 nm wavelength if the output energy of two wavelengths are at the same level.