An Optimized Calibration Method for Integrated Nephelometer: A Case Study in Winter Shanghai

The optical properties of aerosol particles was monitored and studied by using an integrated nephelometer as an method for measuring the scattering coefficient of aerosol particles. Since the truncation angle of nephelometer is limited to the instrument aperture. There is a scattering blind spatial solid angle of less than 10° and more than 171°, so the instrument results need to be corrected. Based on the data obtained from the integrated nephelometer (Aurora 3000) in Shanghai, the correction factor was calculated for the measurement of aerosol optical properties at three wavelengths ( λ = 450 nm, 525 nm, 635 nm). The uncertainty of correction factors was determined. Combined with particles size distribution, measured scattering coefficient and absorption coefficient to obtain the variation range of atmosphere aerosol complex refractive index (m=n+ki) by means of aoptimization inversion method. In this work, determine the angle sensitivity function (Phase function), particle number distribution and refractive index were used to calculate the integral, by comparing the theoretical scattering coefficient with the measured scattering coefficient. In addition, Angstrom exponent (A) and single scattering albedo (ω) can be accurate determined.