The diagram shows the global radiation at Verigas hill near Kirkenes, measured with a thermopile based pyranometer. Global radiation is defined as the total short-wave radiation from the sky falling onto a horizontal surface on the ground. It is the sum of both the direct solar radiation and the diffuse radiation resulting from reflected or scattered sunlight. 
A common solar panel has an efficiency of circa 20 %, but is mounted tilted. Hence the energy yield might be about 25-30 % of the global radiation values.