Moon data pipeline

Builds compact, honest Moon artifacts for the Phase 3 globe, from free, public-domain sources. See docs/MOON_DATA_SOURCES.md and docs/MOON_PHYSICS.md for the full source, license, and methodology record.

The Moon has no atmosphere, so there is no weather. The honest, physically-real "predictive/dynamic" signals are surface-temperature swings, illumination / day-night, libration, and phase — never a fabricated weather feed.

build_diurnal_temperature.py — lunar day-night temperature swing (flagship)

Produces public/data/moon/diurnal_temperature.json: the lunar diurnal surface-temperature curve (surface temperature vs local solar time) at several latitudes. The Moon's day-night swing is ~300 K with no atmosphere to buffer it — the strongest honest "dynamic" Moon signal.

What it is (and is not)

• It is a documented physical model, anchored to LRO Diviner's measured day/night temperature extremes.
• It is not a live sensor feed and not the raw Diviner archive. Labeled as such in the JSON _comment and in MOON_PHYSICS.md.

Model

• Daytime (sunlit side): radiative equilibrium, exactly Eq. 1 of Williams et al. 2017 — T(i) = [ S (1 − A) cos(i) / (ε σ) ]^(1/4) — with the Diviner team's published latitude-dependent albedo A(lat) = 0.08 + 0.045·(lat/45)³ + 0.14·(lat/90)⁸, emissivity ε = 0.95, solar constant S = 1370 W/m², Stefan-Boltzmann σ = 5.670374419e-8. Incidence cos(i) = cos(lat)·cos(h), hour angle h = (LST−12)·15° (sub-solar point on the equator; the Moon's ~1.54° obliquity to the ecliptic makes this near-exact).
• Nightside: instantaneous equilibrium has no thermal inertia and collapses to 0 K, which is unphysical. Instead the nightside is a Diviner-anchored cooling curve from the measured post-sunset value (~120 K, equator) toward the measured pre-dawn minimum (~95 K, equator), scaled by latitude. The surface never drops below this floor, so near the terminator we take max(equilibrium, night_floor) — retained regolith heat holds the surface up at sunrise/sunset.

Data source and licensing

• Data archive (anchors): LRO Diviner Global Data Record, LRO-L-DLRE-5-GDR-V1.0, NASA PDS Geosciences Node (Washington University, St. Louis): https://pds-geosciences.wustl.edu/missions/lro/diviner.htm
• License: public domain (NASA / US Government work, 17 U.S.C. § 105).
• Primary references:
  • Williams, J.-P., et al. (2017), The global surface temperatures of the Moon as measured by the Diviner Lunar Radiometer Experiment, Icarus 283, 300-325, doi:10.1016/j.icarus.2016.08.012 (open access).
  • Vasavada, A.R., et al. (2012), Lunar equatorial surface temperatures and regolith properties from the Diviner Lunar Radiometer Experiment, JGR 117, E00H18, doi:10.1029/2011JE003987.
  • Paige, D.A., et al. (2010), Diviner Lunar Radiometer Observations of Cold Traps in the Moon's South Polar Region, Science 330, 479-482, doi:10.1126/science.1187726.

Running

python scripts/moon/build_diurnal_temperature.py \
    --out public/data/moon/diurnal_temperature.json
# custom latitudes / time step:
python scripts/moon/build_diurnal_temperature.py --lats 0,15,45,75,85 --step 0.25

No third-party deps (stdlib only). The script fails loudly if the equatorial daytime peak drifts outside Diviner's measured 387-397 K band. Verified output 2026-07-06: equator max 391.1 K / min 95.5 K (swing 295.6 K), matching Diviner's measured ~392 K / ~95 K / ~300 K; JSON ~8.9 KB.

Optional / next layers

• Terrain relief (LOLA): the ldem_4.tif (1440×720) LOLA displacement map in the NASA SVS CGI Moon Kit is a public-domain, web-friendly source for vertical relief / bump mapping later. See MOON_DATA_SOURCES.md §3.
• Libration / phase / sub-solar + sub-Earth points: computed client-side (owned by another agent's lib/), no data file needed. Method and constants in MOON_DATA_SOURCES.md §4 and MOON_PHYSICS.md.