SCIAMACHY Absorbing Aerosol Index ? calibration issues and global results from 2002?2004

M. de Graaf (1) , P. Stammes (1)

1 KNMI - Royal Netherlands Meteorological Institute

The validity of the Absorbing Aerosol Index (AAI) product from the SCanning Imaging Absorption SpectroMeter for Atmospheric CartograpHY (SCIAMACHY) is discussed. The operational SCIAMACHY AAI product suffers from calibration errors in the reflectance as measured by SCIAMACHY and design errors. Therefore, the AAI product was recalculated, compensating for the errors, with reflectance data from the start of measurements of SCIAMACHY until December 2004. Appropriate correction factors were determined for the UV to correct for the radiometric error in the SCIAMACHY reflectances. The algorithm was provided with LookUp Tables in which a good representation of polarisation effects was incorporated, as opposed to the LookUp Tables of the operational product, in which polarisation effects were not accounted for. The results are presented, their validity discussed, and compared to the operational product. The AAI is very sensitive to calibration errors and can be used to monitor calibration errors and changes. From 2004 onwards, the new SCIAMACHY AAI is suitable to add to the continuation of the long-term AAI record. Recommendations are given for improvement of the operational AAI product.

Domaines: Océan, Atmosphère

M. de Graaf, P. Stammes. SCIAMACHY Absorbing Aerosol Index ? calibration issues and global results from 2002?2004. Atmospheric Chemistry and Physics Discussions, 2005, 5 (3), pp.3367-3389. ⟨hal-00301464⟩