基于光声光谱和腔衰荡光谱的气溶胶光学特性测量研究

气溶胶光学特性是影响大气辐射强迫的重要因素, 对全球气候起着决定性作用。针对当前气溶 胶光学特性测量仪器存在的测量参数单一、测量不确定度高和溯源体系不完善等问题,本文 将光声光谱(PAS)技术和光腔衰荡光谱(CRDS)技术相结合,实现了气溶胶的消光、吸收及散 射系数同时在线测量, 并研制了一套大气气溶胶多光学参数的高精度在线测量装置。本文测量装置经过NO₂气体 标准物质校准 后,用于大气气溶胶光学特性测量,具有测量相对误差小于4%、测量重复性优于0. 2%和测量不确定 度为2.8%(k=2)等优点。与积分浊度计 、黑碳仪现场实验数据比较,本文测量装置的消光系数、吸收 系数和散射系数的E_n值均小于1,显示出良好的测量一致性和 稳定性。实验结果表明,本文测量装置具备 多参数测量能力,且测量结果准确可靠,可用于大气气溶胶光学特性的现场实时测量,也可 用于相 关测量仪器的计量校准,为测量仪器提供量值溯源。

Aerosol optical property measurement based on photoacoustic spectroscopy and cavity ring-down spectroscopy

To solve the problems of single parame ter,high measurement uncertainty and incomplete traceability system existing in the aerosol optical c haracteristic measurement instrument, we combine photo-acoustic spectroscopy (PAS) with optical cavity ring down spec troscopy (CRDS) and realize simultaneous measurement of aerosol extinction,absorption and scattering coeffi cients with the proposed online and high-precision measurement device.The device with NO_2stand ard gas material calibration can be applied in the measurement of the atmospheric aerosol optical properties,wit h the measuring relative error,repeatability and uncertainty less than 4%,0.2% a nd 2.8% (k=2) respectively.Compared with the aethalometer and nephelometer,the E_n values of extinct ion coefficient,absorption coefficient and scattering coefficient of the device are all less than 1,which indicates good consiste ncy and stability.Experimental results show that the device has the ability to measure multi-parameter and the measurement results are accurate and reliable,which can be used for the real-time measurement of the optical pr operties of atmospheric aerosol and for the calibration of other measurement instruments to provide traceability.