LONG TERM SOLAR CYCLE INDICES Sunspot number R 10( solar min)≤R≤150( olar max) olar flux 10.7 Radio emission line of fe (2800 MHz) Related to variation in euv Measures effect of sun on our atmosphere Measured in solar flux units(10-22 w/m2 50(solar min)sF107 s240(solar maxLONG TERM SOLAR CYCLE INDICES 5 • Sunspot number R 10 (solar min) d R d 150 (solar max) • Solar flux F10.7 Radio emission line of Fe (2800 MHz) Related to variation in EUV Measures effect of sun on our atmosphere Measured in solar flux units (10-22 w/m2) 50 (solar min) d F10.7 d 240 (solar max)