Preprints
https://doi.org/10.5194/amt-2020-412
https://doi.org/10.5194/amt-2020-412

  15 Jan 2021

15 Jan 2021

Review status: this preprint is currently under review for the journal AMT.

New correction method of scattering coefficient measurements of a three-wavelength nephelometer

Jie Qiu1, Wangshu Tan1,2, Gang Zhao1,3, Yingli Yu4,1, and Chunsheng Zhao1 Jie Qiu et al.
  • 1Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, China
  • 2School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
  • 3State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
  • 4Economics & Technology Research Institute, China National Petroleum Corporation, Beijing 100724, China

Abstract. The aerosol scattering coefficient is a significant parameter for estimating aerosol direct radiative forcing, which can be measured by nephelometers. Currently, nephelometers have the problem of non-ideal Lambertian light source and angle truncation. Hence, the observed raw scattering coefficient data need to be corrected. In this study, based on the random forest machine learning model, we have proposed a new method to correct the scattering coefficient measurements of a three-wavelength nephelometer, Aurora 3000, under different relative humidity conditions. The result shows that the empirical corrected values match Mie-calculation values very well at all the three wavelengths and under all the measured relative humidity conditions, with more than 85 % of the corrected values in error by less than 2 %. The correction method is valid to obtain scattering coefficient with high accuracy and there is no need for additional observation data.

Jie Qiu et al.

Status: open (until 12 Mar 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • CC1: 'Comment on amt-2020-412', Jonathan Taylor, 18 Jan 2021 reply
  • RC1: 'Comment on amt-2020-412', Anonymous Referee #1, 06 Feb 2021 reply
  • RC2: 'Comment on amt-2020-412', Anonymous Referee #3, 15 Feb 2021 reply
  • RC3: 'Comment on amt-2020-412', Anonymous Referee #2, 16 Feb 2021 reply

Jie Qiu et al.

Jie Qiu et al.

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Short summary
Considering nephelometers' major problem, a new correction method based on machine learning model is put forward. Our newly proposed method has the advantage of obtaining data with high accuracy while achieving self-correction, which means that researchers can get more accurate scattering coefficient without the need for additional observation data. This method provides a more precise estimation of the aerosol's direct radiative forcing and then the effects on Earth climate system.