| Abstract: | Irradiance records of the Nimbus-7 and SMM satellites indicate a systematic downward trend of the solar constant of the order of a few hundredths of a percent and a slow variation of the solar constant on a time scale from days to weeks. The reason for the downward trend is not known as yet; it seems that the slow variation of the solar constant is linked with the solar rotation period via the effect of solar active regions. This paper deals with the connection between the solar constant variation and the age of the solar active regions. It seems that decreases in the solar constant took place when sunspot groups developing quickly in time and space with complex structure occurred on the solar disk. On the other hand, when the “older” groups with simple structure were dominant the value of the solar constant increased slightly or these groups could reduce the effects of “younger” groups. |
