Journal article
Retrieval of aerosol microphysical properties from AERONET photopolarimetric measurements: 2. A new research algorithm and case demonstration
Journal of geophysical research. Atmospheres, Vol.120(14), pp.7079-7098
07/27/2015
DOI: 10.1002/2015JD023113
Abstract
A new research algorithm is presented here as the second part of a two‐part study to retrieve aerosol microphysical properties from the multispectral and multiangular photopolarimetric measurements taken by Aerosol Robotic Network's (AERONET's) new‐generation Sun photometer. The algorithm uses an advanced UNified and Linearized Vector Radiative Transfer Model and incorporates a statistical optimization approach. While the new algorithm has heritage from AERONET operational inversion algorithm in constraining a priori and retrieval smoothness, it has two new features. First, the new algorithm retrieves the effective radius, effective variance, and total volume of aerosols associated with a continuous bimodal particle size distribution (PSD) function, while the AERONET operational algorithm retrieves aerosol volume over 22 size bins. Second, our algorithm retrieves complex refractive indices for both fine and coarse modes, while the AERONET operational algorithm assumes a size‐independent aerosol refractive index. Mode‐resolved refractive indices can improve the estimate of the single‐scattering albedo (SSA) for each aerosol mode and thus facilitate the validation of satellite products and chemistry transport models. We applied the algorithm to a suite of real cases over Beijing_RADI site and found that our retrievals are overall consistent with AERONET operational inversions but can offer mode‐resolved refractive index and SSA with acceptable accuracy for the aerosol composed by spherical particles. Along with the retrieval using both radiance and polarization, we also performed radiance‐only retrieval to demonstrate the improvements by adding polarization in the inversion. Contrast analysis indicates that with polarization, retrieval error can be reduced by over 50% in PSD parameters, 10–30% in the refractive index, and 10–40% in SSA, which is consistent with theoretical analysis presented in the companion paper of this two‐part study.
Key Points
A new aerosol retrieval algorithm for AERONET polarimetric measurements
Retrieve size and refractive index for both fine‐ and coarse‐mode aerosols
Promising results with real data, limitations, and next research steps discussed
Details
- Title: Subtitle
- Retrieval of aerosol microphysical properties from AERONET photopolarimetric measurements: 2. A new research algorithm and case demonstration
- Creators
- Xiaoguang Xu - University of Nebraska–LincolnJun Wang - University of Nebraska–LincolnJing Zeng - University of Nebraska–LincolnRobert Spurr - RT Solutions IncXiong Liu - Harvard‐Smithsonian Center for AstrophysicsOleg Dubovik - Laboratoire d'Optique Atmosphérique, CNRS–Université de Lille 1Li Li - Institute of Remote Sensing and Digital Earth of Chinese Academy of SciencesZhengqiang Li - Institute of Remote Sensing and Digital Earth of Chinese Academy of SciencesMichael I Mishchenko - NASA Goddard Institute for Space StudiesAliaksandr Siniuk - NASA Goddard Space Flight CenterBrent N Holben - NASA Goddard Space Flight Center
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Atmospheres, Vol.120(14), pp.7079-7098
- DOI
- 10.1002/2015JD023113
- ISSN
- 2169-897X
- eISSN
- 2169-8996
- Number of pages
- 20
- Grant note
- Glory Mission Program NASA Radiation Sciences Program NASA Earth and Space Science Fellowship
- Language
- English
- Date published
- 07/27/2015
- Academic Unit
- Electrical and Computer Engineering; Civil and Environmental Engineering; Iowa Technology Institute; Physics and Astronomy; Chemical and Biochemical Engineering
- Record Identifier
- 9984104911502771
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