AVHRR - Aerosol Optical Thickness

World Meteorological Organization

Daily, weekly, and monthly global 1 degree maps of Aerosol Optical Thickness derived from the AVHRR instrument onboard the NOAA satellites. The weekly products are based on a composite of one week's worth of data, and the monthly mean products are based on the average of each week's data for the month. Currently they are created from AVHRR channel 1, 2 and 3 optical thickness retrievals from AVHRR 4-km global area coverage (GAC) data.

Satellite NOAA (NOAA)
Instrument(s) AVHRR
Instrument / Algorithm PI A. Ignatov, NOAA
Contact Details alex.ignatov[at]noaa.gov
Parameter(s) AOD
Aerosol algorithm AEROBS
Cloud screening CLAVR/CLAVR-x
Aerosol model non-absorbing w. monomodal lognormal size distribution
Retrieval assumptions ocean reflectance is accurately calculated
Retrieval limitations glint area (<40° glint angle) & solar side of orbit are excluded;
View and solar zenith angles > 60° are excluded
Spatial, temporal coverage global oceans, 1988 onward
Spatial, temporal resolution 8 km/daily, 110 km analysis/day/week, month
Operations status Operational / reprocessing
Validation status AERONET & other satellite inter-comparison studies
Quality control self- and inter-consistency checks
last algorithm version third-generation algorithm (09/2000)
last validation 07/2002


Algorithm description Product format description
Version explanation Validation summary


Product data access
Image / quicklook data access