Back to the page HelioClim databases icon Last updated - Dernière modification  21/11/08 Mines ParisTech - Armines

The HelioClim-2 Database - Solar Radiation Values Derived from Meteosat Satellites by the Heliosat-2 Method

Parameters - Geographical Coverage - Time Period - Units - Uncertainty - Method - Versions - DNI - Inclined surface - Acknowledgements -

The major paper on HelioClim-2 is the following: Rigollier C., Lefèvre M., Wald L., 2004. The method Heliosat-2 for deriving shortwave solar radiation data from satellite images. Solar Energy, 77(2), 159-169. See publications

Parameters provided: time-series of global irradiation or irradiance

Top Of Page

Geographical Coverage: field of view of Meteosat satellite

Approximately: 66 N - 66 S ; 66 E - 66 W. The field of view is restricted to the pixels belonging to the Earth and for which the elevation angle of Meteosat above horizon is larger than 12 degrees.

Clik on picture for magnification (copyright Eumetsat)

Top Of Page

Time Period

For HelioClim-2: from February 2004 onwards. Satellite data are received at Ecole des Mines de Paris by the means of a receiving station and are processed immediately. They are available 2-3 minutes after end of acquisition. For legal reasons, they are disseminated only 24 hours after.

Top Of Page

Units: Wh/m2, J/cm2, W/m2 (conversion factors)

Top Of Page

Method

The images taken by the satellite Meteosat, are processed by the means of the method Heliosat-2.

Top Of Page

Versions

For HelioClim-2

Version Number Date Comments
Version 1.0 February 2004  
Version 1.0.1 November 2006 Takes into account both satellites Meteosat-8 and -9. More information.
Known defects:
- There is a difference between the monthly mean of irradiance, the monthly mean of daily mean of irradiance and the monthly mean of hourly mean of irradiance. Differently said, there is a difference between the monthly irradiation whether it is delivered by the button "month" or "day" or "hour" in the SoDa Service. The relative magnitude of the difference reaches a maximum of approx. 1 % during winter when the sun is low above horizon; it is negligible in summer. The difference originates from the coding of data in the hourly and daily databases (digitization step) plus rounding numerical effects.
- The irradiance is underestimated during the afternoon in sites located east of 30 deg in desertic areas with local relief. This is due to the combination of local shadowing and large albedo of the ground.

Top Of Page