SOLAR SPECTRAL IRRADIANCE

The solar luminosity (total radiant power emitted) is 3.86⋅10

26

W, of which 1373 W/m

2

reaches the top of the earth’s atmosphere.

To a zeroth approximation the sun can be considered a black body

with an effective temperature of 5780 K, which implies a peak in

the radiation at around 0.520 µm (5200 Å). The actual solar spec-

tral emission is more complex, especially at ultraviolet and shorter

wavelengths. The graph below, which was taken from Reference

1, summarizes the solar irradiance at the top of the atmosphere in

the range 0.3 to 10 µm.

References

1. Jursa, A. S., Ed., Handbook of Geophysics and the Space Environment,

Air Force Geophysics Laboratory, 1985.

2. Pierce, A. K., and Allen, R. G., “The Solar Spectrum between 0.3 and

10 µm” , in The Solar Output and Its Variation, White, O. R., Ed.,

Colorado Associated University Press, Boulder, CO, 1977.

3. Lang, K. R., Astrophysical Data. Planets and Stars, Springer-Verlag,

New York, 1992.

2000

1800

1600

1400

1200

1000

800

600

400

200

0

0.3

0.4

0.5

0.7

1.0

2

3

4

5

6

7

8

9 10

X10

Wavelength in

µm

Irradiance in

W m

-2

µ

m

-1

14-18

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