The Global and Diffuse Solar Radiation Trends Using GEBA & BSRN Ground Based Measurements during 1984–2018

Abstract

Surface solar radiation (SSR) is a crucial parameter for both the Earth’s climate and human activities, and it consists of two components: the direct beam from the sun and diffuse radiation, with the latter being scattered by atmospheric molecules, aerosols, or clouds. The multidecadal variations of SSR, known as Global Dimming and Brightening (GDB), should also arise from a corresponding variability of either the direct or the diffuse radiation. Thus, the determination of the trends of both the direct and the diffuse radiation is important for showing the causes of GDB. In the present study, we estimate the trends of global and diffuse radiation on a global scale during the period 1984–2018, using worldwide reference ground-based measurements from the Global Energy Balance Archive (GEBA) and the Baseline Surface Radiation Network (BSRN). An increasing tendency of SSR is observed over most locations on our planet, while a decreasing trend occurs in India. On the other hand, the diffuse radiation has decreased over Europe and parts of Asia, whereas it has increased over the USA, India, and East Asia.

Keywords

• surface solar radiation
• global dimming and brightening
• diffuse solar radiation
• direct solar radiation
• ground based measurements