Rocky Mountain Research Station

Title: Validation and understanding of Moderate Resolution Imaging Spectroradiometer aerosol products (C5) using ground-based measurements from the handheld Sun photometer network in China

Author: Li, Zhanqing; Niu, Feng; Lee, Kwon-Ho; Xin, Jinyuan; Hao, Wei Min; Nordgren, Bryce L.; Wang, Yuesi; Wang, Pucai

Date: 2007

Source: Journal of Geophysical Research. 112: D22S07. doi: 10.1029/2007JD008479.

Description: The Moderate Resolution Imaging Spectroradiometer (MODIS) currently provides the most extensive aerosol retrievals on a global basis, but validation is limited to a small number of ground stations. This study presents a comprehensive evaluation of Collection 4 and 5 MODIS aerosol products using ground measurements from the Chinese Sun Hazemeter Network (CSHNET). The Collection 5 product uses a new method to determine the surface reflectance and a new aerosol model to retrieve aerosol optical thickness (AOT). Substantial improvement was found in the Collection 5 AOT product relative to the Collection 4 AOT product. Overall, the correlation coefficient of regression with ground measurements increased from 0.66 to 0.84 for all data points. The offset is reduced from 0.179 to 0.047, and the slope is improved from 0.74 to 0.98. At individual sites, the improvement varies with surface and atmospheric conditions. In general, both versions of the MODIS aerosol product tend to overestimate AOT over deserts/ semideserts, tend to underestimate AOT over forests, and are more accurate over agricultural and suburban sites. The poorest retrievals occur over urban areas. The land cover dependence of aerosol retrievals was traced to the estimation of surface reflectance. The selection of the aerosol type is another major factor contributing to the discrepancies. Errors caused by both factors are subject to considerable variations with season and location due to land cover changes and varying fractions of coarse and fine mode aerosols, as well as the changing amount of scattering and absorbing aerosols.

Keywords: Moderate Resolution Imaging Spectroradiometer (MODIS), Chinese Sun Hazemeter Network (CSHNET)

View and Print this Publication (1.2 MB)

Publication Notes: 

• We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
• This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

 Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility

Citation

Li, Zhanqing; Niu, Feng; Lee, Kwon-Ho; Xin, Jinyuan; Hao, Wei Min; Nordgren, Bryce L.; Wang, Yuesi; Wang, Pucai  2007.  Validation and understanding of Moderate Resolution Imaging Spectroradiometer aerosol products (C5) using ground-based measurements from the handheld Sun photometer network in China.   Journal of Geophysical Research. 112: D22S07. doi: 10.1029/2007JD008479..