MarsUpperAtmosphere: Response to SolarActivity

Upper atmosphere parameters of planets such as Earth,Venus and Marsthatarecontrolledbyabsorptionofsolareuvradiation–100nmƒareknown to show a variability with solar activity since this radiation canvary by about100% between low and high solar activity. Although theintensity of solar euv £uxes has been directly measured only intermit-tently and never on a long term basis, the relative sunspot numbers R