An overview of surface solar radiation data products at the German meteorological service

The surface solar radiation is an important component of the Earths energy budget and has long been the focus of research on climate change, e.g. in order to close the earth’s energy budget or to track long-term changes. The Global Water and Energy Exchanges (GEWEX) program has been at the forefront of research in that field. Due to the worldwide efforts in the transition of the energy system, the importance of surface solar radiation data products has grown even more in recent years and is of interest for many applications and research fields. There has been a long history of measuring and providing sunshine duration and, later on, solar radiation data from a comprehensive surface network in Germany since the beginning of the measurements in the 19th century. With the advent of meteorological satellites, methods for calculating surface solar radiation were developed based on observations from space, providing a spatially more complete data coverage. This article presents and describes the available observational data sources and the derived products of gridded solar radiation offered by Deutscher Wetterdienst (DWD) and provides guidance to the user for their use in several application areas. The different data properties, including the timeliness (delay between measurement and publication), available length of the time series and spatiotemporal resolutions, determine the potential applications of the data. Some of the presented data records are more focused on climate (like those from the EUMETSAT Satellite Application on Climate Monitoring – ‘CM SAF’) while others are focused on real-time provision of the data (like the ‘DUETT’ data, combining station and satellite measurements). All presented data sets are publicly available.