Comparison of Aerosol Products Retrieved from AERONET, MICROTOPS and MODIS over a Tropical Urban City, Pune, India

Sanjay More; P. Pradeep Kumar; Pawan Gupta; P.C.S. Devara; G.R. Aher

doi:10.4209/aaqr.2012.04.0102

Comparison of Aerosol Products Retrieved from AERONET, MICROTOPS and MODIS over a Tropical Urban City, Pune, India

Sanjay More¹, P. Pradeep Kumar¹, Pawan Gupta², P.C.S. Devara³, G.R. Aher ⁴

¹Department of Atmospheric and Space Sciences, University of Pune, Pune – 07, India
²Universities Space Research Association, Columbia, MD 20771, USA
³Indian Institute of Tropical Meteorology, Pune-8, India
⁴Physics Department, Nowrosjee Wadia College, Pune-01, India

Received: April 24, 2012
Revised: August 20, 2012
Accepted: August 20, 2012
Download Citation: ||https://doi.org/10.4209/aaqr.2012.04.0102

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Cite this article:
More, S., Kumar, P.P., Gupta, P., Devara, P. and Aher, G. (2013). Comparison of Aerosol Products Retrieved from AERONET, MICROTOPS and MODIS over a Tropical Urban City, Pune, India. Aerosol Air Qual. Res. 13: 107-121. https://doi.org/10.4209/aaqr.2012.04.0102

ABSTRACT

Aerosol Optical Depth (AOD) measurements from Aerosol Robotic NETwork (AERONET; level 2.0), Microtops - II sun-photometer and MODerate Resolution Imaging Spectroradiometer (MODIS) (Terra and Aqua; level 2, collection 5, dark target) were compared and used to characterize aerosols over Pune, India. AODs from Microtops and MODIS were compared with those measured by AERONET to evaluate the measurement quality. To the best of our knowledge, this is the first systematic comparison of MODIS aerosol products over Pune, India. The results of the analysis show that during 2008–10, 68% to 84% of the MODIS AODs fell within an expected error, as defined by the MODIS science team, and thus the retrievals from this system are validated and accepted. In addition, during pre-monsoon periods MODIS retrievals are better-matched with ground-based measurements. On the seasonal scale, MODIS retrievals corroborate well with ground-based measurements, with correlation coefficients ranging from 0.62 to 0.93. Despite an overall satellite-ground agreement, MODIS tends to under-estimate AOD during winter, and this may be due to improper assumptions of surface reflectance and the incorrect selection of aerosol types. AERONET retrieved single scattering albedo (SSA) values in winter (0.82–0.86), suggesting the dominance of absorbing aerosols, slightly increased (0.87–0.89) in pre-monsoon season, indicating more scattering type of aerosols. These values are about 8.9%–1.1% lower than those of the assumed SSA values in the MODIS algorithm.

Keywords: AOD; MODIS; AERONET; Inter-comparison; MICROTOPS