Mars GCM configuration¶
Mars supplies body constants, forcing and boundary data to the generic JAX GCM.
The primary spatial workflow lives in src.celestials.planets.mars.maps; it does
not advance the deprecated torch Mars.compute_derivatives state.
From planet to spatial state¶
- Build spectral/sigma coordinates and body-based units from
MARS_BODY_3D. - Load checksum-verified MOLA terrain and transform it to the modal lower boundary.
- Initialize a terrain-balanced atmosphere or load a compatible full-state restart.
- Attach radiation, surface properties, dust and CO₂ forcing.
- Integrate coupled dynamics and surface reservoirs, optionally with diffusion.
- Export dimensional fields, sampling metadata, diagnostics and restart state.
The initial hydrostatic pressure uses Mars gravity, gas constant and temperature:
p_s(z) = p0 * exp(-g*z/(R*T)). Winds and circulation subsequently evolve under
the primitive equations; terrain is not just a plotting overlay.
Physics configuration¶
| Process | Selection and behavior |
|---|---|
| Solar geometry | Keplerian season/orbit; diurnal or daily-mean illumination; solar slant path |
| Radiation | Grey, explicit compact multiband, or bundled Ames correlated-k CO₂ |
| Surface exchange | Conservative sensible heat and momentum drag; optional stability dependence |
| Regolith | Optional multilayer conduction and TES thermal-inertia/albedo fields |
| PBL/convection | Conservative diffusion and smooth dry convective relaxation |
| CO₂ | Pressure-dependent frost point, surface latent heat and atmosphere/frost exchange |
| Dust | Prescribed opacity, optionally separate visible/IR seasonal climatology |
| Diffusion | Optional spectral damping selected by physical e-folding timescale |
The factory's generic defaults are deliberately smaller than the browser baseline.
run_maps() with no forcing is dry dynamics. tform mars maps enables grey
daily-mean radiation and CO₂ by default. The server enables correlated-k radiation
and advanced surface physics, longwave scales 0.25/0.25, surface exchange 1.0,
and a 0.1-sol diffusion timescale, using staged TES/Ames data when available.
See the configuration quickstart.
Outputs and comparison¶
Forced temperature maps are surface skin temperature; dry maps use lowest-layer air temperature. Winds represent the lowest sigma layer rather than fixed 10 m. Frost is pressure-equivalent (Pa); divide by gravity for kg/m². Full-state comparison exports also provide atmospheric profiles and forcing metadata. Match season, averaging, height and dust before interpreting reference differences.
Calibration, neural components and limits¶
Physical calibration fits separate CO₂/dust longwave and surface-exchange multipliers through coupled trajectories. Neural radiation replaces directional fluxes with constrained boundary conditions; neural heating is bounded but can add net energy. Cached temperature-only fitting is a separate downstream workflow.
The model has no water/cloud cycle, interactive dust lifting or photochemistry. Composition-dependent high-pressure terraforming physics is not validated. Recorded multi-year atmospheric/surface repeatability passed selected thresholds, but deep-soil equilibrium did not. See validation.
Deprecated model and intervention semantics¶
The torch global-mean derivation is retained for existing users and is deprecated. Current multi-year browser intervention trajectories still use it, with independent GCM diagnostic spin-ups at selected years. They are not continuous 3-D intervention forecasts. Use coupled GCM experiment workflows for new spatial-model research and disclose this limitation for old runs.