The HelioClim databases

Last updated - Dernière modification 21/11/08 Mines ParisTech - Armines

The HelioClim-1 Database - Solar Radiation Values Derived from Meteosat Satellites by the Heliosat-2 Method

Parameters - Geographical Coverage - Time Period - Units - Uncertainty - Method - Versions - Acknowledgements -

The major paper on HelioClim-1 is the following: Lefèvre M., Wald L., Diabaté L., 2007. Using reduced data sets ISCCP-B2 from the Meteosat satellites to assess surface solar irradiance. Solar Energy, 81, 240-253. See publications

Parameters provided: time-series of global irradiation or irradiance

time-series of radiation values: from daily to monthly values. Values are irradiance in W/m² as well as irradiation in Wh/m² and J/cm².
irradiance at top of atmosphere
irradiance under clear-sky
uncertainty values
information on the number of data used to compute the radiation value

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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)

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Time Period

For HelioClim-1: 1985-2005.

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

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Method

The images taken by the satellite Meteosat, are processed by the means of the method Heliosat-2 to derive the surface solar irradiance. The detailed procedure is described in Lefèvre M., Wald L., Diabaté L., 2007. Using reduced data sets ISCCP-B2 from the Meteosat satellites to assess surface solar irradiance. Solar Energy, 81, 240-253. See publications

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Versions

For HelioClim-1

Version Number	Date	Comments
Version 2.1	21 January 2005	Known defects: 1. Spatial discontinuity of the radiation field off the coasts of Senegal 2. Too low values for the Eastern half of the Arabian Peninsula 3. Too low values for Northern latitudes ( > 50 °N)
Version 3.0	4 March 2005	Corrects for the defects 1 and 2 mentioned above. The database was reconstructed. Version 3.1 contains a new format of the outputs. In January 2005, error in navigation was discovered in original Meteosat images. This leads to strong errors in places close to marked orographic features, such as coastlines, especially those bordering deserts, or mountains.
Version 4.0	9 March 2006	Corrects for the defects mentioned above. The database was reconstructed. Results are close to those of Version 3, except for places mentioned above.

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