Retrieval of surface solar irradiance, based on satellite-derived cloud information, in Greece

• MSG cloudiness was used for GHI and DNI calculations in Greece.
• The results were compared with the ground measurements.
• Monthly and annual climatologies of GHI and DNI are provided.

Cloud properties derived from the SEVIRI (Spinning Enhanced Visible and Infrared Imager) instrument, on board the MSG (Meteosat Second Generation) satellite, have been used to retrieve the surface global solar irradiance incident on a horizontal surface GHI (global horizontal irradiance) and the DNI (direct normal irradiance) with a temporal resolution of 15 min. The daily amount of solar energy as well as monthly and annual sums, are estimated. Based on a 6-year study period (2008–2013), a monthly climatology is derived. Results are compared with ground-based measurements in Greece. Comparison shows a general good agreement between satellite and ground data, with the highest differences occurring in cases of broken or very thick cloudiness. The highest collected monthly solar energy values are found during summer months, in Southern Peloponnese, Crete and Cyclades islands, and exceed 250 kWh m−2. The annual average energy for GHI is 1400–1500 kWh m−2 in Northern Greece and up to 1900 kWh m−2 in Southern Peloponnese, Crete and the islands. For DNI, values increase to about 9% in Northern Greece and around 15% in Southern Greece.