Earth radiation

Fig. 17-1. Electromagnetic spectrum. Note the regions of solar and earth radiation...

Fig. 17-4. Radiation heat balance. The 100 units of incoming shortwave radiahon are distributed reflected from earth s surface to space, 5 reflected from cloud surfaces to space, 20 direct reaching earth, 24 absorbed in clouds, 4 diffuse reaching earth through clouds, 17 absorbed in atmosphere, 15 scattered to space, 9 scattered to earth, 6. The longwave radiation comes from (1) the earth radiating 119 units 101 to the atmosphere and 18 directly to space, and (2) the atmosphere radiating 105 units back to earth and 48 to space. Additional transfers from the earth s surface to the atmosphere consist of latent heat, 23 and sensible heat, 10. Source After Lowry (4).

Harrison, E. F., P. Minnis, B. R. Barkstrom, V. Ramanathan, R. D. Cess, and G. G. Gibson, Seasonal Variation of Cloud Radiative Forcing Derived from the Earth Radiation Budget Experiment, J. Geophys. Res., 95, 18687-18703 (1990). 

SAGE II sage in Experiment 1 Stratospheric Aerosol and Gas Experiment II Stratospheric Aerosol and Gas Experiment 111 profiles O3, NO2, H2O, aerosols 03, OCIO, BrO, NO2, NO3 aerosols NASA Earth Radiation Budget Satellite (1984 - present) Meteor 3M (2001) Intema-tional Space Station (2002)... 

The atmosphere absorbs radiation quite selectively in narrow-wavelength bands. The absorption for solar radiation occurs in entirely different bands from the absorption of the radiation from the earth because of the different spectrums for the two types of radiation. In Fig. 8-65 we see the approximate spectrums for solar and earth radiation with some important absorption bands... 

Ramanathan, V. (1987) The role of earth radiation budget studies in climate and general circulation research, J. Geophys. Res. 92, 4075-4095. 

Ramanathan, V., Cess, R. D., Harrison, E. F., Minnis, P., Barkstrom, B. R., Ahmad, E., and Hartmann, D. (1989) Cloud-radiative forcing and climate Results from the earth radiation budget experiment, Science 243, 57-63. 

This estimate of forcing can be compared with the estimate derived from the Earth Radiation Budget Experiment (ERBE) compared with a total absence of clouds on the Earth, the presence of clouds increases the global average reflection of shortwave radiation by about 50 Wm-2 (Hartmann 1993). 

Background Radiation is a term that causes fearful responses in people. However, not all radiation is dangerous. We are surrounded by radiation from space and from natural radioactivity on Earth. Radiation can also be used in a safe and controlled way for medical purposes. 

Table 2.16 Earth radiation budget in % of incoming solar radiation (100% = 343 W m ). fl, input, tt output, IR infrared radiation.

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