Variability of Shortwave and Longwave Radiation over Europe as Derived from International Satellite Cloud Climatology Project

Abstract

Solar radiation is the major source of energy for the earth‐atmosphere system. The absorbed shortwave radiation is re‐emitted as infrared radiation (longwave radiation) by the system. Fluctuations of the levels of both radiations are responsible for the changes of energy budget at the Earth’s surface. The variability of the solar and earth radiation may originate from the variability of astronomical parameters, the sun’s activity and natural or anthropogenic processes. In this study, the variability of both the solar radiation at the earth’s surface and the emitted longwave radiation is studied. The dataset includes down‐welling shortwave and up‐welling longwave radiation for the area of Europe and was obtained from the International Satellite Cloud Climatology Project (ISCCP). The data cover the time period from 1984 to 2006 with a spatial analysis of 280 km2 and a temporal analysis of 3 hours. During the examined time period many of the anthropogenic processes, like energy needs, car technology, biomass burning and industrial activity, have been modified in Europe. This study includes the analysis of short and long‐term radiation variations caused by natural and anthropogenic factors and also attempts to quantify the alterations on the radiation levels.