Accurate time series on available solar radiation at ground level and its diffuse component are required worldwide for industrial, as well as for scientific, purposes. However, the sparse sampling of the worldwide distribution of ground based measurements does not meet the requirements of the different user groups. The SUNSAT project was initiated to calculate the global radiation and its diffuse component, as well as to handle the statistics from the METEOSAT B2-ISCCP satellite data set. These observations cover the continents of Africa and Europe, the Middle East and wide regions of the Atlantic and Indian Oceans.
An atlas has been produced with results for the time period (1985 to 1986) presented as coloured images, with a spatial resolution of 0.5 degrees by 0.5 degrees, and in the form of tables. The tables contain averages over areas of 2.5 degrees by 2.5 degrees longitude and latitude. To ensure the accuracy of these retrieved solar radiation fields at ground level, a comparison with all available ground based pyranometer measurements was made. The results of the surface measurements and the satellite estimates presented in this atlas coincide well.
DUE TO THE FACT, THAT THE TRANSMITTANCE OF THE ATMOSPHERE AND ITS CLOUDS ARE INVERSELY RELATED TO THE REFLECTANCE FOR SOLAR RADIATION, VALUES OF THE GLOBAL RADIATION AT GROUND CAN BE DETERMINED FROM DIGITAL SATELLITE IMAGES MEASURED IN THE SPECTRAL RANGE OF SOLAR RADIATION. FIRST ESTIMATES HAVE SHOWN THAT MONTHLY AVERAGES OF GLOBAL RADIATION ARE ACCURATE WITHIN 8 TO 9%.
WITHIN THE PROJECT SUNSAT, THE GLOBAL RADIATION REACHING EUROPE AND AFRICA WILL BE DETERMINED FOR A PERIOD OF 2 COMPLETE YEARS (JAN.1985 - DEC.1986) FROM THE ROUTINELY COLLECTED 3-HOURLY LOW SPATIAL RESOLUTION (30-50 KM) METEOSAT 2 ISCCP DATA SET. THE 1/2-HOURLY HIGH RESOLUTION (2.5-5.0 KM) METEOSAT 2 DATA WILL BE USED TO DETERMINE THE GLOBAL RADIATION OVER THE RESTRICTED AREA OF THE SAHEL ZONE FOR JUNE AND DECEMBER 1985 AND 1986. ADDITIONALLY, FOR GROUND TRUTH COMPARISON, AS MANY AS POSSIBLE PYRANOMETER MEASUREMENTS MADE OVER THE AFRICAN CONTINENT DURING 1985 TO 1986 WILL BE COLLECTED.
THE FIRST YEAR OF DATA IS NOW PROCESSED AND PRELIMINARY ESTIMATES OF THE GLOBAL RADIATION ARE DISTRIBUTED AMONG THE SUNSAT MEMBERS. AFTER FINAL QUALITY CONTROL MAPS OF GLOBAL RADIATION WRITTEN ON 1600 BPI CCTS WILL BE AVAILABLE ON REQUEST AT THE UNIVERSITY OF KOLN.
Funding SchemeCSC - Cost-sharing contracts