Determination of the global solar irradiation by MSG-SEVIRI images processing in Algeria

摘要

To evaluate the hourly and daily global solar irradiation received on a horizontal surface at the ground in Algeria, we have applied a physical model to the Meteosat second generation images (MSG). This model is GISTEL (Solar Radiation by Teledetection), initially built by C. Delorme in 1987 to estimate daily solar irradiation in France from B2 images collected by Meteosat 2. In this study, this model is used to process MSG-2 images. The resolution of these images equals 3 km × 3 km,. They were collected every fifteen minutes, in twelve channels of different wavelengths. Among these channels, only the two visible channels (VIS006 and VIS008) for February 2011 are considered. The method so developed aims at looking for a correspondence between the radiometric value of each pixel position (line, column) on the image, and the global solar irradiation received at the ground. Thus, we calculated the global solar irradiation for the station of Tamanrasset located at the south of Algeria (latitude 22.78°N, longitude 5.51°E). The obtained results were then compared to the ground solar measurements recorded by a pyranometer in this station for February 2011. It was found that the MSG-SEVIRI estimated values are close to the ground measurements. In particular, the correlation coefficient is about 77% on an hourly basis and 96% on a daily basis.