Sunspots and Increased Solar Irradiance

did you ever wonder why increased solar activity - i.e., an increased number of sunspots - correlates with increased solar irradiance? this should seem counterintuitive, since sunspots are "cool" (~4000K, versus the surrounding photosphere's ~5800K) areas on the sun, caused by the presence of intense magnetic activity inhibiting the process of convection. well, after a bit of searching, it turns out that sunspots are generally accompanied by so-called faculae (latin for "small torch"), which actually increase the solar irradiance (enough to more than compensate for the decrease caused by sunspots). according to researchers at the institute for solar physics in stockholm,

"the density of the gas is strongly reduced by the presence of strong magnetic fields. the low density of that gas makes it nearly transparent, such that we can see the deeper layers of the granule on the limb-side of the magnetic field concentration. at these deeper layers, the gas is hotter and radiates more strongly, explaining the brightening."

i'm still confused, but apparently people are modeling these things, so it's nontrivial. (image credit: swedish solar telescope)