JAXA Lunar and Planetary
Exploration Data
Analysis group

ACTIVITY What We Are Working On

Estimating Lunar Surface Temperatures

We use visualizations of observation data and numerical simulations to produce surface temperature estimates to figure out the surface temperature of the Moon.

Developing a Temperature Observation Data Visualization Tool

NASA’s Lunar Reconnaissance Orbiter was equipped with an instrument called Diviner to observe surface temperatures on the Moon. We are now developing a tool to visualize the data obtained by Diviner.

Observation vs. modeling
Illustration 1: (Left) Example of visualized observation data near the lunar south pole. (Right) Temperature changes in the areas indicated by small circles, graphed using all observation data from 2010-2011. This visualizes the difference between temperature changes in an area with frequent sunshine and an area where the sun hardly ever shines. Since the angle of the Moon’s rotation changes relative to its orbital plane, the altitude of the Sun also gradually changes. （ Large image）

Temperature Simulations

We simulate temperature changes on Moon’s surface to learn about temperatures at times that have not been observed.

Illustration 2: Surface simulation results in the south pole vicinity. Since only topographical data for this range is entered, note that sunlight which does not actually enter the large crater at the right of the screen is shown to be entering it.
Observation vs. modeling
Illustration 3: (Left) Shaded relief of the area around the south pole. (Center) Temperature profiles at each location. Sunlight conditions are good and relatively consistent with each other. (Right) Temperature profiles at each location. An example of locations that are inconsistent with each other. We can see there are locations heavily impacted by secondary light, and locations from which part of the solar disc is always visible or no part is ever visible. The challenges going forward will be to improve calculation speed and to perform calculations using radiated light and even higher-resolution topographic data. （Large image）
Illustration 4: Example of a numerical simulation performed in a lunar region south from 80° (when only measuring direct light). Temperature near the lunar south pole is extremely low, and is thought to hardly rise at all throughout a day on the Moon. Water ice is therefore expected to exist in shallow spaces below ground in this area.