Rayleigh atmosphere

TABLE 4.1 Relation between the Slant Path Optical Depth m and sec 0 for a Standard Rayleigh Atmosphere... 

At sea level the Rayleigh atmosphere has an extinction coefficient bCM of approximately 13.2 x 10 6m l at X = 520 nm wavelength, limiting visibility in the cleanest possible atmosphere to about 296 km. Rayleigh scattering decreases with altitude and is proportional to air density. At X = 520 nm wavelength ... 

Prepare a log-log plot of rx versus X and evaluate the slope as a test of the Rayleigh theory applied to air. The factor M/pN in Eq. (10.36) becomes 6.55 X 10 /No, where Nq is the number of gas molecules per cubic centimeter at STP and the numerical factor is the thickness of the atmosphere corrected to STP conditions. Use a selection of the above data to determine several estimates of Nq, and from the average, calculate Avogadro s number. The average value of n - 1 is 2.97 X 10" over the range of wavelengths which are most useful for the evaluation of N. ... 

Rayleigh scattering accounts for only a minor part of the extinction, except on the clearest days. It is a function of atmospheric pressure alone and... 

The Rayleigh scattering extinction coefficient for particle-free air is 0.012 km for "green" light (y = 0.05 /rm) at sea level (4). This permits a visual range of —320 km. The particle-free, or Rayleigh scattering, case represents the best visibility possible with the current atmosphere on earth. 

Fig. 10-5. Comparison of for 0.1 ppm NO2 and Rayleigh scattering by air. The photopic eye response represents the range of wavelengths over which the eye detects light. Source Husar, R., White, W. H., Paterson, D. E., and Trijonis, J., "Visibility Impairment in the Atmosphere," Draft report prepared for the U.S. Environmental Protection Agency under Contract No. 68022515, Task Order No. 28.

Rayleigh Scattering the scattering of light by particles much smaller than the wavelength of the light, e.g., molecular scattering in the natural atmosphere. 

Figure 2. Magnitude of Rayleigh and sodium backscatter return as a function of atmospheric density.

Lord Rayleigh finds that atmospheric nitrogen is heavier than nitrogen from the decomposition of ammonia. 

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