Figure 1: Spectral solar irradiance outside the atmosphere and at sea level,
in both cases with the sun at the zenith and for a mean Earth-sun separation. Shaded areas indicate absorption at sea level due to the atmospheric constituents shown (from [97], adapted from [98]).
For comparison of Figures 1, 3 and 4: 1000 W m-2 µm-1 = 100 mW cm-2 µm-1 = 1 mW cm-2 (10 nm)-1