Configuring AGNI

AGNI configuration files are formatted using TOML. There are examples in res/config/. The default configuration file contains comments explaining the purpose of each parameter. Take care to format the variables in the TOML file correctly. There are no 'default values': not all parameters are required in all cases, but the model will return an error naming any parameters which are both necessary and absent.

Run AGNI with a specific configuration file by passing its path as an argument:

./agni.jl res/config/hotdry.toml

Configuration sections

The configuration files are broken into four sections (or "tables"). A full description of every parameter is given in the Configuration reference.

[planet] - General properties of the planet: surface temperature, instellation, gravity, stellar spectrum properties, and surface material.
[files] - Input/output files and other paths: spectral file, stellar spectrum, output directory, and optional RFM parameter file.
[composition] - Atmospheric composition and chemistry. There are three main ways to set the composition: partial pressures (p_dict), mixing ratios (vmr_dict or vmr_file), or by metallicities (metallicities).
[execution] - Parameters that control what the model does: number of levels, solver choice, solution type, convergence tolerances, initial temperature profile, and runtime limits.
[physics] - Physics toggles: convection, condensation, chemistry, real-gas EOS, continua, Rayleigh scattering, clouds, sensible heat.
[plots] - Toggle which diagnostic plots are generated by AGNI.

Choosing a solution type

The execution.solution_type integer tells AGNI what atmospheric state to solve for:

1 – Conserve energy fluxes with fixed surface temperature (planet.tmp_surf).
2 – Conserve energy fluxes with the surface temperature set by heat conduction through a solid conductive boundary layer; requires planet.skin_d, planet.skin_k, and planet.tmp_magma.
3 – Solve for a state where the net flux at each level equals planet.flux_int (radiative equilibrium).

See Obtaining a solution in the model description for a detailed explanation.

Choosing a solver

The execution.solver string selects the numerical solver:

"" (empty) – no solving; fluxes are calculated from the initial state only.
"newton" – Newton-Raphson algorithm.
"gauss" – Gauss-Newton algorithm.
"levenberg" – Levenberg–Marquardt algorithm.
"transparent" – use when composition.transparent=true.

Setting the initial temperature profile

execution.initial_state is an ordered list of descriptors applied in sequence to build the starting T(p) profile. Available descriptors:

Descriptor	Argument	Effect
`dry`	–	Dry adiabatic lapse rate from the surface upwards
`str`	`tmp`	Isothermal stratosphere at temperature `tmp`
`iso`	`tmp`	Set the whole atmosphere isothermal at `tmp`
`csv`	`pth`	Load profile from a CSV file at path `pth`
`sat`	`gas`	Clausius-Clapeyron saturation curve for gas `gas`
`ncdf`	`pth`	Load profile from a NetCDF file at path `pth`
`loglin`	`tmp`	Log-linear profile between `tmp_surf` and `tmp` at the top
`ana`	–	Guillot (2010) analytical solution

Example: initial_state = ["dry", "sat", "H2O", "str", "180"] applies the dry adiabat from the surface, the water condensation curve above that, then an isothermal stratosphere at 180 K. Use tmp="Teq" to substitute the planet's radiative equilibrium temperature automatically.

Gas opacity overlap method

physics.overlap_method tells SOCRATES how to combine gas opacities in mixtures:

"ee" – equivalent extinction (fastest)
"rorr" – random overlap with resorting and re-binning
"ro" – random overlap (most accurate, slowest)

See Amundsen+2017 for a comparison.

Transparent atmosphere

Setting composition.transparent = true configures a transparent (opacity-free) atmosphere. This is useful for computing bare-rock emission spectra or surface temperatures without an overlying atmosphere. When enabled, use solver = "transparent" and omit all other [composition] parameters.