The eruptive events, though extremely energetic and potentially hazardous, are very short-lived and thus have a minor effect on the overall radiation from the Sun. Sunspots and faculae, though localized, have a measurable impact on the overall radiation at the Earth. If we compare the radiation coming from the Sun, at all wavelengths, at times when the magnetic field structures are weakest - the so-called solar minimum - with the times of solar maximum, then we see that the magnitudes of the variations differ substantially with wavelength. Even though the total variation (all wavelengths combined) is 0.1%, in certain regions of the ultraviolet wavelengths, the variations are up to 100%! It is the variations in these wavelengths which are crucial to an understanding of how certain chemical species (e.g., ozone) vary in response to changing solar activity.
Approved by Peter Fox
Last revised: Mon Apr 10 15:08:11 MDT 2000