Solar Energy Absorbed by Earth
§  Solar Constant (S)
   = solar flux density reaching the Earth
   = 1370 W/m2
§  Solar energy incident on the Earth
   = S x the “flat” area of the Earth
   = S  x p R2Earth
§  Solar energy absorbed by the Earth
   = (received solar flux) – (reflected solar flux)
   = S p R2Earth  – S p R2Earth  x  A
   = S p R2Earth   x  (1-A)

  A is the planetary albedo of the Earth, which
  is about 0.3.