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Advances in Meteorology
Volume 2010 (2010), Article ID 147910, 12 pages
http://dx.doi.org/10.1155/2010/147910
Research Article

Aerosol Monitoring over Athens Using Satellite and Ground-Based Measurements

1Atmospheric Research Team, Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Lofos Nymphon, P.O. Box 20048, 11810 Athens, Greece
2Institute for Space Applications and Remote Sensing, National Observatory of Athens, Metaxa & Vas. Pavlou, Pendeli, 15236 Athens, Greece

Received 27 June 2009; Revised 25 October 2009; Accepted 2 December 2009

Academic Editor: Krishnaswamy Krishnamoorthy

Copyright © 2010 D. G. Kaskaoutis et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Satellite data of moderate spatial resolution (MODIS and MERIS) were used to retrieve the aerosol optical depth (AOD) over the urban area of Athens. MODIS products were obtained at a horizontal resolution of 10 by 10  k m 2 centered over Athens, while the differential textural analysis (DTA) code was applied to MERIS images to retrieve relative-to-reference AOD with a resolution of 260 m by 290 m. The possibility of exploiting the full resolution of MERIS data in retrieving AOD over a grid of a few hundreds metres was thereby investigated for the first time. MERIS-based AOD, centred at 560 nm, showed strong positive correlation to ground-based P M 1 0 data ( 𝑅 2 = 0.85), while MODIS AOD products were in agreement with both MERIS and P M 1 0 . Back trajectories were used to study the impact of atmospheric conditions prevailing during the examined days. Days associated with Saharan air masses corresponded to enhanced AOD and predominance of coarse-mode particles. The results suggest that, at least for the case of Athens, AOD retrieved by MERIS images using the DTA code over cloud-free areas can be related to P M 1 0 . The accuracy of retrieval mainly depends on the successful selection of the reference satellite data, namely, an image being least contaminated by tropospheric aerosols.