Solar radiation transfer through the atmosphere

The solar constant 4 represents a radiant flux E (energy area  

Only about 30 % of the solar energy intercepted at the top of earth s atmosphere passes directly through to the surface (cf. Fig. 2.13). On the way through the atmosphere, direct solar radiation undergoes scattering, absorption and reflection on molecules and suspended particles, such as dust particles and cloud droplets (Fig. 2.14). 

Therefore, and due to global averaging (/jf/4), only 240 W m reaches the earth s surface, varying with time and site. 

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