Water vapor, when present, may also play a role; its presence is characterized by the hydrogen emission lines.
Hydrogen from water vapor reduces the oxide, reforming water vapor and continuing this "water cycle".
This is due to the higher altitude which represents a natural water vapor condenser, which is carried by the western and southern winds.
Efforts should focus on areas where there are signs of liquid moisture or water vapor (humidity) or where moisture problems are suspected.
Such a planet would have an atmosphere containing water vapor and free oxygen produced by the breakdown of water by ultraviolet radiation.
One solution corresponds to a planet in the runaway state (warm) and the other solution corresponds to a planet in a stable state with respect to water vapor (cool).
The sinking air is very dry, having lost its water vapor on the way up, and the area under the descending air is generally arid.
The added greenhouse from the water vapor will increase the surface temperature, which will in turn evaporate more water into the atmosphere.
