Four decades (and counting) of Satellite-based Surface Solar Radiation data - The CM SAF SARAH-3 and CLARA-A3 Climate Data Records

The incoming surface solar radiation is an essential climate variable as defined by GCOS. Long term monitoring of this part of the earth’s energy budget is required to gain insights on the state and variability of the climate system. In addition, climate data sets of surface solar radiation have received increased attention over the recent years as an important source of information for solar energy assessments, for crop modeling, and for the validation of climate and weather models; all applications are requiring high-quality and temporally-consistent data records.

Gridded regional and global data records of the surface irradiance are available based on satellite measurements as well as derived from numerical models, e.g., reanalysis systems. For climatological analyses, long-term data records, covering multiple decades, are required. SARAH-3 and CLARA-A3, the satellite-based climate data records from the EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF), provide data for more than 4 decades already, starting in 1983 and 1979, respectively, and are providing temporally consistent near real-time data.

Here, we present the surface solar radiation data from the SARAH-3 and the CLARA-A3 climate data records for Europe. Evaluation results using surface reference data from BSRN / GEBA and other sources document the quality of the satellite-based data in terms of accuracy and temporal stability. The variability, the changes, and the trends in surface radiation are presented and discussed. Additional data, e.g., top-of-atmosphere fluxes and cloud coverage, are used to assess potential causes for the trends and variabilities found in the surface solar radiation in Europe.