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Aerosol optical thickness and spatial variability along coastal and offshore waters of the eastern Arabian Sea

Menon, HB and Sangekar, N and Lotliker, A and Moorthy, KK and Vethamony, P (2011) Aerosol optical thickness and spatial variability along coastal and offshore waters of the eastern Arabian Sea. ICES Journal of Marine Science, 68 (4). pp. 745-750.

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Abstract

Data from the ocean-colour monitor (OCM) on board the Indian Remote Sensing Satellite P4 were used to analyse the spatial and temporal distribution of aerosol optical thickness (AOT) over the coastal and offshore waters of the eastern Arabian Sea. Zero water-leaving radiance from the near infrared (NIR) region was assumed for oceanic (open ocean) waters, because of the absorption of longwave radiation by water molecules. As this assumption fails in coastal waters, it was necessary to correct for water-leaving radiance and sun glint to the NIR bands. The aerosol size-distribution parameter (α) was derived from a relationship between two NIR bands. The A°ngström turbidity parameter (β) was obtained using an algorithm relating in situ hand-held, sun-photometer measurements and aerosol radiance (L a) at 490 nm. The relationship between β and L a (490) was derived with a sensitivity analysis, using a calibrated radiative transfer model. AOTs were retrieved for each pixel of 500 nm. The algorithm's performance was tested by comparing OCM-derived AOT values with in situ AOT and MODIS-derived values. Aerosol maps thus generated from January to December 2005 demonstrate the potential of this new retrieval method for producing AOT climatology from OCM data over coastal waters.

Item Type: Article
Additional Information: Copyright of this article belongs to International Council for the Exploration of the Sea.
Uncontrolled Keywords: aerosol optical thickness coastal waters eastern Arabian Sea offshore spatial variability
Subjects: Oceanography > oceanography
Depositing User: INCOIS Library
Date Deposited: 08 Dec 2013 09:28
Last Modified: 08 Dec 2013 09:28
URI: http://moeseprints.incois.gov.in/id/eprint/181

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