Assessing Surface Solar Irradiance in French Guiana using the Heliosat-II method and GOES images

Abstract:

French Guiana is an overseas department administratively attached to France, located in the northeast of South America between Brazil and Surinam. French Guiana’s distance from France (more than 8000 km) leads to varied needs, especially in energy supply. A promising solution for solar mapping of French Guiana lies in the use of satellite images as the few ground radiometric stations (6 stations) are not sufficient to create a solar mapping of French Guiana. In this work, we assess the use of the Heliosat-II method with GOES satellite images in order to develop a dynamic solar map in French Guiana. To estimate Surface Solar Irradiance (SSI) over French Guiana, the original Heliosat-II method developed for operation with METEOSAT images has been modified to be used with GOES satellite images. Modifications include a change in calibration and in the calculation of the cloud albedo. Cloud albedos were retrieved using several strategies proposed by the literature: the maximum monthly value of the apparent albedo values (ρc max), the 95th percentile of the apparent albedo values (ρc Q95) or a pixel-by-pixel formula (ρc Rig). ). By using these three different methods, SSI was calculated over French Guiana. SSI estimated with ρc max as the cloud albedo gives the best results, with an overall MBE lesser than 5% and a Correlation Coefficient greater than 0.9, for a RMSE of 25% . These results show that the use of the Heliosat-II method with GOES images provide accurate SSI estimates in French Guiana.