Articles | Volume 15
https://doi.org/10.5194/asr-15-31-2018
https://doi.org/10.5194/asr-15-31-2018
18 Apr 2018
 | 18 Apr 2018

Satellite-based trends of solar radiation and cloud parameters in Europe

Uwe Pfeifroth, Jedrzej S. Bojanowski, Nicolas Clerbaux, Veronica Manara, Arturo Sanchez-Lorenzo, Jörg Trentmann, Jakub P. Walawender, and Rainer Hollmann

Abstract. Solar radiation is the main driver of the Earth's climate. Measuring solar radiation and analysing its interaction with clouds are essential for the understanding of the climate system. The EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) generates satellite-based, high-quality climate data records, with a focus on the energy balance and water cycle. Here, multiple of these data records are analyzed in a common framework to assess the consistency in trends and spatio-temporal variability of surface solar radiation, top-of-atmosphere reflected solar radiation and cloud fraction. This multi-parameter analysis focuses on Europe and covers the time period from 1992 to 2015. A high correlation between these three variables has been found over Europe. An overall consistency of the climate data records reveals an increase of surface solar radiation and a decrease in top-of-atmosphere reflected radiation. In addition, those trends are confirmed by negative trends in cloud cover. This consistency documents the high quality and stability of the CM SAF climate data records, which are mostly derived independently from each other. The results of this study indicate that one of the main reasons for the positive trend in surface solar radiation since the 1990's is a decrease in cloud coverage even if an aerosol contribution cannot be completely ruled out.

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Short summary
Measuring solar radiation and analysing its interaction with clouds are essential for the understanding of the climate system. Trends in EUMETSAT CM SAF satellite-based climate data records of solar radiation and clouds are analysed during 1992–2015 in Europe. More surface solar radiation and less top-of-atmosphere reflected radiation and cloud cover is found. This study indicates that one of the main reasons for the positive trend in surface solar radiation is a decrease in cloud cover.