Evaluation of the MERIS aerosol product over land with AERONET

International audience The Medium Resolution Imaging Spectrometer (MERIS) launched in February 2002 on-board the ENVISAT spacecraft is making global observations of top-of-atmosphere (TOA) radiances. Aerosol optical properties are retrieved over land using Look-Up Table (LUT) based algorithm and sur...

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Bibliographic Details
Main Authors: Vidot, J., Santer, R., Aznay, O.
Other Authors: Department of Atmospheric and Oceanic Sciences Madison, University of Wisconsin-Madison, Laboratoire Interdisciplinaire des Sciences de l'Environnement
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2008
Subjects:
Online Access:https://hal.archives-ouvertes.fr/hal-00328311
https://hal.archives-ouvertes.fr/hal-00328311/document
https://hal.archives-ouvertes.fr/hal-00328311/file/acpd-8-3721-2008.pdf
Description
Summary:International audience The Medium Resolution Imaging Spectrometer (MERIS) launched in February 2002 on-board the ENVISAT spacecraft is making global observations of top-of-atmosphere (TOA) radiances. Aerosol optical properties are retrieved over land using Look-Up Table (LUT) based algorithm and surface reflectances in the blue and the red spectral regions. We compared instantaneous aerosol optical thicknesses retrieved by MERIS in the blue and the red at locations containing sites within the Aerosol Robotic Network (AERONET). Between 2002 and 2005, a set of 500 MERIS images were used in this study. The result shows that, over land, MERIS aerosol optical thicknesses are well retrieved in the blue and poorly retrieved in the red, leading to an underestimation of the Angstrom coefficient. Correlations are improved by applying a simple criterion to avoid scenes probably contaminated by thin clouds. To investigate the weakness of the MERIS algorithm, ground-based radiometer measurements have been used in order to retrieve new aerosol models, based on their Inherent Optical Properties (IOP). These new aerosol models slightly improve the correlation, but the main problem of the MERIS aerosol product over land can be attributed to the surface reflectance model in the red.