AERUS-GEO at ICARE

This page provides a summary documentation of the AERUS-GEO (Aerosol and surface albEdo Retrieval Using a directional Splitting method – application to GEOstationary data) products available at ICARE and how to access the data.

ICARE routinely acquires SEVIRI Level-1B data from SATMOS/CMS in near-real time. ICARE is in charge of the data processing to generate the daily aerosol products using the AERUS-GEO science code provided by the French CNRM laboratory, and streamlined to run in the ICARE production environment.
ICARE is also in charge of the archiving and distribution of these science products to the user community through the online archive, FTP, or SSH (see the Data Access section below for data availability and access procedures).
In addition, ICARE provides browse images associated with the generated products. Imagery over the whole SEVIRI archive (2005 to present) is available through ICARE's multi-sensor web interface and geostationary browse interface, for comparison to many other data sets (satellite sensor retrievals, AERONET data), including the GEMS/MACC aerosol forecast, to facilitate observation/model comparisons.

Summary

Aerosols play a key role in the study of climate, weather forecast, air quality, civil aviation, and other important topics. These atmospheric particles are related to a rapid temporal variation and they are heterogeneously distributed over the surface of the Earth. In this context spaceborne remote sensing represents the only viable tool to detect, characterize and monitor aerosols at the regional and global scales.

The AERUS-GEO approach developed by the CNRM laboratory (Centre National de Recherches Météorologiques; Univ. de Toulouse, Météo France, CNRS) efficiently processes observations from the SEVIRI camera aboard the geostationary satellite Meteosat Second Generation (MSG) for the estimation of aerosol and surface properties [1][2]. The retrieval strategy separates the contributions related to the aerosols and the surface thanks to the directional and temporal inspection of the satellite signal, which is modeled using a kernel based model. A simplified Kalman filter approach is used for the mathematical inversion of this model and for the propagation in time of the retrieved information and the associated uncertainties.

The outputs of the AERUS-GEO approach include a daily-averaged Aerosol Optical Thickness (AOD) at 0.635 micrometers, the Angström exponent between 0.635 and 1.64 micrometers, and the associated uncertainties and quality flag. All variables are disseminated in the native SEVIRI geostationary grid. Figure 1 shows the RGB image at noon and spatial distribution of the daily AOD at 0.635 μm for March 30th, 2010 (click to enlarge).

SEVIRI RGB image SEVIRI AERUS image

Figure 1: For March 30th, 2010, (left) SEVIRI RGB composite at noon and (right) daily AOD at 0.635 μm retrieved by AERUS-GEO


A comparison of the reanalyzed daily AOD values against the concomitant ground measurements acquired by the AERONET stations within the MSG disk for the period between 2006 to 2010 is shown in Figure 2. It can be seen that the retrieved AOD are unbiased and well correlated with respect to AERONET data. Other studies underlined the notable accuracy of AOD retrieved by AERUS-GEO when compared to AERONET and other satellite aerosol products [3].

SEVIRI RGB image
Figure 2: Comparison between AERUS-GEO derived AOD at 0.635 μm with respect to concomitant AERONET measurements


Nowadays, the CNRM works towards the development of an instantaneous version of AERUS-GEO, which will provide an estimate of the AOD for each SEVIRI observation (every 15 minutes). This work is justified by the variations of the aerosol load during the day, which may show a 30% departure with regard to the daily averaged AOD. These differences justify the retrieval of the diurnal cycle of aerosols, which constitutes a current need of the climate and weather scientific communities.

Data Access

Access to the data is subject to the Data Policy below. All users must register beforehand. Registered users can access the data through the Archive Web Interface and the FTP server. ICARE provides a web interface dedicated to geostationary products to visualize AERUS-GEO browse images.

ICARE archive and FTP access
Two types of daily aerosol products derived by AERUS-GEO are available:

Geostationary browse interface
Quicklooks of AERUS-GEO products (along with other products and color composites) can be visualized on the ICARE web interface dedicated to geostationary products: http://www.icare.univ-lille1.fr/browse/geoview.php
  • MSG/SEVIRI AERUS-GEO 0.63µm Daily (daytime) Aerosol Optical Depth
  • MSG/SEVIRI AERUS-GEO Daily (daytime) Angstrom Exponent
For example, to view the daily AOD at 0.635 μm for March 30th, 2010, enter 2010-03-30 for the date and select "MSG/SEVIRI AERUS-GEO 0.63µm Daily (daytime) Aerosol Optical Depth" in the drop-down product selection list
or enter the URL with specified date and product:
http://www.icare.univ-lille1.fr/browse/geoview.php?dataset=seviri_aerus_aod06&date=20100330&coastlines=true

Data Policy

The AERUS-GEO products distributed by ICARE are public and free of charge.
Publications using AERUS-GEO products must include the following sentence:
AERUS-GEO products was developed in the framework of a joint collaboration between AERIS/ICARE Data and Services Center, EUMETSAT, and CNRM/Météo-France. Products are generated and distributed by AERIS/ICARE Data and Services Center (http://www.icare.univ-lille1.fr)"
Short credit:
CNRM/Météo-France/EUMETSAT/AERIS/ICARE

Contacts

For more information regarding product access, registration, or any technical information, please contact contact@icare.univ-lille1.fr
The technical point of contact at ICARE (responsible for the maintenance of the processing chain) is Bruno Six.

For science questions about the AERUS-GEO products, please contact:
Dr. Dominique Carrer – Principal Investigator
Dr. Xavier Ceamanos – Researcher
Dr. Suman Moparthy – Algorithm & validation expert


References

[1] Carrer, D., Ceamanos, X., Six, B., and Roujean, J.-L. (2014), AERUS-GEO: a newly available satellite-derived aerosol optical depth product over Europe and Africa, GRL, 41, 7731-7738.

[2] Carrer, D., Roujean, J.-L., Hautecoeur, 0., and Elias, T., (2010), Daily estimates of aerosol optical thickness over land surface based on a directional and temporal analysis of SEVIRI MSG visible observations, Journal of Geophysical Research-Atmospheres, Vol. 115, D10208.

[3] H. Xu, X. Ceamanos, J.-L. Roujean, D. Carrer, and Y. Xue, Can satellite-derived aerosol optical depth quantify the surface aerosol radiative forcing? Atmospheric Research, Vol. 150, Dec. 2014, pp. 151-167