World Meteorological Organization

Multi-Sensor algorithm combining GOME-2 Polarization Monitoring Devices (PMD) and AVHRR (+ IASI in future releases). Cloud fractions, cloud correction factors for GOME-2 PMD, aerosol classification (volcanic ash, dust, strong or weak coarse mode) are determined from AVHRR. A set of AOD for different microphysical properties is retrieved using one GOME-2 PMD band around 640nm. The best solution of this set is found using a fit over all GOME-2 PMD bands using both reflectances and stokes fractions.

Example result

Instrument(s) GOME-2, AVHRR
Contact details Rosemary.Munro[at]
Parameter(s) AOD, volcanic ash flag
Aerosol algorithm PMAp
Cloud screening

AVHRR operational cloud mask + PMAp cloud screening

Aerosol model up to 28 combinations of microphysical properties stored in a LUT, only a subset of 3-6 cases are fitted dependent on conditions
Retrieval assumptions ocean surface described by Cox-Monk, case-I-water only, aerosol microphysics retrieval based on wavelength dependence of the reflectance and stokes fractions
Retrieval limitations no retrievals for areas affected by glint, no retrieval in case of thick clouds, currently no retrieval over land (anticipated for next major version)
Spatial, temporal coverage April 2014 - ongoing, NRT, ocean
Spatial, temporal resolution 5x40km (METOP-A), 10x40km (METOP-B), 9:30 equator crossing time
Operations status operational
Validation status validated: AERONET, ECHAM model, MODIS
Quality control

Continuous monitoring of NRT data against AERONET, continuous monitoring of instrument status and NRT processing quality indicators, error estimation

last algorithm version 1.0.10
last validation 2/2015


Algorithm description Product format description
Version explanation Validation summary


Product data access
Image / quicklook data access