Insolation
Atmosphere is not transparent for all the radiation coming from the sun because of different composition and layers.   It is  also  one  of  the  controlling  factors of  insolation to  reach  earth surface. The   atmosphere   is   composed   of   gases,   water   vapour   and particulate   matters.The atmosphere  is  a  mixture  of  gases,such  as nitrogen(N),  oxygen  (O2), Argon, carbon  dioxide, Neon  (Ne),  Helium  (He),  Methane  (CH4),  Krypton  (Kr),  Ozone  (O3),  Nitrous  oxide  (N2O), Hydrogen (H) and Xenon (Xe). The atmosphere also contains water vapour, water in the gaseous state.