中文摘要：

为研究本征荧光对生物气溶胶粒子探测精度的影响,本文在阐述生物气溶胶荧光光谱信号探测原理的基础上,设计了一台紫外激光诱导荧光雷达.该雷达选用波长为266 nm的四倍频固体激光器作为激励光源,基于本征荧光波长、探测距离等主要参数,对生物气溶胶荧光光谱回波信号的信噪比及粒子浓度的最小分辨率进行数值仿真分析.仿真结果表明,在探测误差小于10%的情况下,距离为1.5 km时,系统对生物气溶胶荧光波长的有效探测范围为300—800 nm;而在距离为2.1 km时,荧光波长的有效探测范围为300—310 nm.此外,在探测距离定义为0.1 km,荧光波长为350和600 nm时,系统对物气溶胶粒子浓度的最小分辨率分别为2个颗粒/L和4个颗粒/L,最小分辨率的差值为2个颗粒/L.仿真结果有利于了解荧光波长变动时激光雷达系统的探测准确度,进而实现大气生物气溶胶更加有效的探测.

英文摘要：

Biological aerosols which could cause diseases of human beings, animals and plants, are living particles suspended in the atmosphere. Ultraviolet laser induced fluorescence has been developed as a standard technique used to discriminate between biological and non-biological particles. As an effective tool of remote sensing, fluorescence lidar is capable of detecting concentration of biological aerosols with high spatial and temporal resolutions. Intrinsic fluorescence, one of the most important characteristics of biological aerosols, has quite a large effect on the performances of fluorescence lidar. To investigate the effects of intrinsic fluorescence on biological aerosols, we design an ultraviolet laser induced fluorescence lidar at an excited wavelength of 266 nm, with a repetition rate of 10 Hz. Fluorescence signals are collected by a Cassegrain telescope with a diameter of 254 mm, in which fluorescence spectra of 300-800 nm are mainly considered. A spectrograph and a multichannel photomultiplier tube（PMT） array detector are employed to achieve the fine separation and highefficiency detection of fluorescence signals. According to the present configuration, we perform a series of simulations to estimate the measurement range and the concentration resolution of biological aerosols, with a certain pulse energy. With a relative error less than 10%, theoretical analysis shows that designed fluorescence lidar is able to detect the biological aerosols within a range of 1.5 km at a concentration of 1000 particles·L^-1. When the detection distance enlarges to 2.1 km, detectable wavelength range is limited to 300–310 nm. In addition, the lidar is capable of identifying minimum concentrations of biological aerosols with 2 particles·L^-1 and 4 particles·L^-1 at fluorescence wavelengths of 350 nm and 600 nm, respectively, where the induced pulse energy is set to be 60 m J and detected range 0.1km. With setting energies of 40 m J and 20 m J, minimum concentrations of biological aerosols decrease to 3 particles·L