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15. November 2021

The effects of water and air currents on the planetary heat flow equilibrium

Let's begin with the observation that the earth receives approximately as much energy from the sun (i.e. 173000 TW annually) as it emits into space. Here's a picture of the mean annual emission in W/m2.
What I'd like to do in this post is to study the effects associated with water and air currents on a theoretical unperturbed heat flow equilibrium.

Let's begin with water currents. Horizontal surface currents:
  • warm current => moister air,
  • cold current => drier air,

vertical surfacing currents:

  • cold current => heat sucked into the sea,
  • warm current => heat released from the sea.

Cold currents surface in warmer places and warm currents surface in colder places, but if a place is colder than 4°C then water density as a function of its temperature and ice and snow conspire to block the heat release, and hence the oceans tend to store any surplus of atmospheric heat, suitable currents provided.

And over to air currents. Vertical upward air currents:

  • land warmer than water => clear skies,
  • water warmer than land => clouds,

in places where there are sufficiently large bodies of water and land sufficiently close to each other to reasonably compare their temperatures. For instance, as long as the Gulf of Finland hasn't frozen over, it will be as steamy as a boiling pot of water on a day where the air temperature has fallen below -15°C. In general we can only say that a dry upward current produces clear skies and a moist one clouds, subject though to the difference in temperature as a function of elevation (as a condition of condensation).

As for clouds:

  • emitted heat > sun radiation => warming effect,
  • emitted heat < sun radiation => cooling effect,

and hence for horizontal surface air currents:

  • dry current and net outgoing radiation => cooling effect,
  • dry current and net incoming radiation => warming effect,
  • moist current and net outgoing radiation => warming effect,
  • moist current and net incoming radiation => cooling effect.

Again, the atmosphere as a whole has a tendency to let heat in by upward currents over land in summer and block its release by upward currents over water in winter, suitably interspersed bodies of land and water provided. There may be a principle involved here, like energy hogging, but that's just a conjecture based on the observation of rather Aristotelian physical patterns (the ascend of a ball on a ballistic curve etc.)

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