Spotless

clipped from www.intellicast.com While irradiance changes just 0.1% over the 11 year cycle, ultraviolet radiation changes 6 to 8% and shorter wavelengths even more. Ultraviolet radiation destroys ozone, an exothermic process which produces warming in the higher atmosphere in low to mid latitudes that works its way down to the middle troposphere in time. Labitzke (2001) has shown statistically significant differences of temperatures in the lower stratosphere into the middle troposphere with the 11 year solar cycle (warmest at max) which she attributes to solar flux induced ultraviolet variance. Shindell et al NASS GISS (1999) showed results from a global climate model including ozone and UV found UV induced stratospheric ozone changes and generated heat that penetrates into the troposphere, in effect confirming Labitzke’s findings.   Also an active sun causes a diffusion of cosmic rays, which have a low cloud enhancement effect through ion mediated nucleation. Low clouds reflect radiation and have a net cooling effect.