ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-9-733-2009 Intercomparison of Aerosol Optical Depth from Brewer Ozone spectrophotometers and CIMEL sunphotometers measurements Cheymol A. 1 Gonzalez Sotelino L. 1 Lam K. S. 2 Kim J. 3 Fioletov V. 4 Siani A. M. 5 De Backer H. 1 Royal Meteorological Institute of Belgium, Dept. of Observations, Avenue Circulaire 3, 1180 Brussels, Belgium Hong Kong Polytechnic University, Dept. of Civil and Structural Engineering, Hong Kong Yonsei University, IEAA BK21 Program, Global Environment Laboratory, Department of Atmospheric Science, Seoul, Korea Environnement Canada, Experimental Studies Section, Science and Technology Branch, 4905 Dufferin Street, M3H 5T4, Toronto, ON, Canada, Department of Physics, University of Rome "La Sapienza", P. le Aldo Moro, 200185 Rome, Italy 29 01 2009 9 2 733 741 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/9/733/2009/acp-9-733-2009.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/9/733/2009/acp-9-733-2009.pdf

The Langley plot method applied on the Brewer Ozone measurements can provide accurate Aerosol Optical Depth (AOD) in the UV-B. We present seven intercomparisons between AOD retrieved from Brewer Ozone measurements at 320 nm and AOD measured by CIMEL sunphotometer at 340 nm or 440 nm (shifted to 320 nm in using the Angström's law), which are stored in the international AERONET database. Only the intercomparisons between co-located instruments can be used to validate the Langley Plot Method applied to the Brewer measurements: in this case, all the correlation coefficients are above 0.82. If the instruments are not at the same site, the correlation between the AOD retrieved by both instruments is much lower. In applying the Angström's law the intercomparison is improved compared to previous study.

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