Temperatures in the Lunar Soil and its Radio Emission
Joachim Köppen Kiel Oct. 2017

Some brief explanations

This simulation computes the temperatures and the radio emission by a patch of the lunar surface, situated in the middle of the lunar face as seen from Earth, both during an entire month and during a total lunar eclipse.

The lunar soil is heated by the solar radiation. This heats up the top layer of a few mm thickness. Since the soil is not a solid rock, but consists of a loose mixture of dust, sand, and small pieces of rock (called 'regolith') due to the break up of the material by the constant impacts of meteroites, there is very little thermal contact between individual pieces. Hence the thermal conductivity of this material is very low, and the transport of heat from the top layer to the layers below is very slow.
The simulation solves the equations of thermal conduction in a vertical column of lunar soil. For simplicity, we assume that the properties of the material do not vary with depth. The top soil is irradiated by the Sun, either with a constant rate or with the monthly variation as the Sun rises and falls above the patch, or during a total lunar eclipse when the Moon goes through the penumbra and the umbra of the Earth shadow with the resulting blocking of the sunlight.

The plot on the left shows the time evolution of the temperatures in different depths or the radio fluxes at different frequencies. The five curves are marked with different colours, which the user can assign to different depths or frequencies, respectively. The plot on the right shows the vertical temperature profiles.
The controls are the following:

Just a word of caution: Please keep in mind that the accuracy of the results depends on the chosen time step. The smaller this value, the better are the results, but they take longer! The largest permissible value depends on the properties assumed for the lunar soil. If you notice the beginning of a zigzag pattern in the curves (in the left image below), you need a lower time step! Otherwise you may end up with a spectacular pattern (right image) which has nothing to do with the lunar soil, but is simply a numerical fantasy!
While there is some degree of checking against unreasonable input values, this is no guarantee that a model computed with parameter values much different from the default values will also give accurate results. When in doubt, it might help to recompute it with a smaller time step ...

Soil properties
heat conductivity [Wm/K]
specific heat [J/kgK]
electr.loss tan(δ)

depth [m] freq.[GHz]

time step [h]
plot after n time steps
clear after n curves

Mouse position:

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