TNO Physics and Electronics Laboratory J. Kusmierczyk-Michulec G. de Leeuw 7 December 2004Aerosol optical thickness retrieval launched in March 2002 high-resolution ( nm) spectrometer wavelength range: nm Swath Dim.: 960 km (cross track) by 25 km (along track at nadir) Nadir scan: 4 pixels of 240 km (cross track) by 25 km (along track) Limb scan: 960 km (cross track) vertical tangential step size 3.0 km The SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) on board the ESA Envisat satellite 7 December 2004Aerosol optical thickness retrieval The Global Ozone Monitoring Experiment (GOME) GOME aboard ERS-2 (courtesy of ESA) Launched in April channel grating spectrometer Spectral resolution nm Wavelength range: nm One across-track : 3 ground pixels: 40 km x 320 km 7 December 2004Aerosol optical thickness retrieval Aerosol retrieval algorithm for SCIAMACHY/GOME where atm = R + a + aR s is the zenith solar angle is the zenith observation angle s - is the relative azimuth between the incident and observation vertical planes 7 December 2004Aerosol optical thickness retrieval Ra is based on the sunphotometer measurements in Ispra ( ) (Holben et al. 1998) Rtoa - GOME data TOA reflectance - example 7 December 2004Aerosol optical thickness retrieval LER-Lambertian Equivalent Reflectance derived from reflectances measured by GOME (R. Koelemeijer et al., 2003) Spectral reflectances of natural surfaces -examples 7 December 2004Aerosol optical thickness retrieval Approach over land/water for GOME Reflectances at TOA measured by GOME (380, 440, 463, 495, 555, 670 nm) Cloud screening FRESCO algorithm (Koelemijer et al., 2001,2002) Correction for ozone absorption Surface correction GOME surface reflectances database LUT of aerosol/atmospheric/Rayleigh reflectances for a given satellite and solar geometry 3 predominantly aerosol types -maritime, - continental, - urban, The best fit with aerosol model AOD 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval Outline 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval 7 December 2004Aerosol optical thickness retrieval We thank the PI investigators: Didier Tanr, Brent Holben, Philippe Goloub and Giuseppe Zibordi, and their staff for establishing and maintaining the AERONET sites used in this investigation. We acknowledge Piet Stammes and Martin de Graaf for kindly providing us GOME data and the results from FRESCO algorithm. The algorithm was developed as part of the EO-037 project of the National Data User Support Program of the Netherlands Space Research Organization (SRON). 7 December 2004Aerosol optical thickness retrieval Illustration of the retrieval process- example 1 7 December 2004Aerosol optical thickness retrieval Illustration of the retrieval process example 2 7 December 2004Aerosol optical thickness retrieval Illustration of the retrieval process example 3 7 December 2004Aerosol optical thickness retrieval