torsdag 27 december 2012

Evidence of Zero Greenhouse Gas Effect 4

The above picture from Giant Planets of Our Solar System by P. Irwin, shows observed cloud structure and temperature variation through the atmospheres of the outer gaseous planets: Jupiter, Saturn, Uranus and Neptune. We find minimum temperature close to observed bolometric temperature as the temperature of a blackbody of the same irradiance:
  • Jupiter: 124 K (167 K)
  • Saturnus:  95 K (138 K)
  • Uranus: 59 K (79 K)
  • Neptunus: 59 K (70 K)
which we can identify as temperatures attained at a pressure of about 0.3 bar (with those at 1 bar in parenthesis).

We compare with a bolometric temperature of the Earth + atmosphere assuming an irradiance of 200 W/m2 = 240 W/m2 absorbed from the Sun (with albedo 0.3) minus 40 W/m2 radiated through the atmospheric window directly from the Earth surface, which equals (200/5.66)^0.25 x 10^2 = 243 K. This is close to the temperature of the Earth atmosphere at 0.3 bar.
We thus find evidence that the bolometric temperature  of a planet including atmosphere, is close to the minimum temperature attained at a pressure of about 0.3 bar, which we may view to define the "outer boundary" of the planet plus atmosphere.

The internal temperature including the temperature of a planet surface would then be determined by the bolometric temperature and a lapse rate specified by thermodynamics, both being independent of the specific radiative properties of the atmosphere, thus supporting the idea of zero greenhouse gas effect. 

1 kommentar:

  1. Very good! It could be that one has to integrate the radiation from an entire range of altitudes and that it happens to fit the 0.3 bar temperature very well.