Take the logarithm to base ten and write pressure in units of , so its argument is dimensionless. Continuity of the atmospheric pressure-temperature profile givesThusIf the logarithm means , the equivalent constant is . A plot of temperature against logarithmic pressure is vertical in each isothermal region and straight between the two endpoints.
Atmospheric pressure-temperature profile
. Details. 
The processes can be organized by the supplied pressure ranges, although the exact boundaries require reaction rates, irradiation and mixing information:
- At , the dense gas can approach thermochemical equilibrium because collisions and reactions are relatively rapid. Deep carbon monoxide and molecular nitrogen can provide reservoirs for transported material.
- At , the falling temperature slows chemical conversion. Vertical transport can produce a chemical quench level when the chemical relaxation time crosses the eddy mixing time. Horizontal chemical quenching is also possible if dayside and nightside conditions differ. Suitable species can condense and undergo atmospheric condensate rainout where a saturation curve is crossed.
- At , slow thermal chemistry permits a quenched atmospheric mixing ratio to survive. Atmospheric photochemistry can dominate where stellar ultraviolet photons penetrate, often at still lower pressures; atmospheric haze may form from its products. Extremely high layers can also experience atmospheric escape.
The profile identifies plausible chemical regimes, but does not fix their transition pressures by itself. In particular, cloud formation depends on the species-specific condensation curve, and ultraviolet processing depends on shielding.
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