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Config Options
Alfrodull shares some options for star and orbit definition with the Double Gray Radiative Transfer module. Alfrodull only options start with the Alf_ prefix. See input file page for description of files used.
star temperature if using a black body spectrum. [Kelvin]
internal temperature (ghost layer temperature), this contributes to the upward flux from the lowest layer, added through Stephan-Boltzmann law at that temperature [Kelvin]
Star radius [R_sun]
Planet to star distance in astronomical units [AU]
true: use isothermal planck function over each layer, simple layers false: use non-isothermal planck function over each layer, split layers
Use thomas solver for flux matrix computation.
If not using thomas solver, Alfrodull uses iterative solver for flux matrix computation. This specifies the number of iterations true: 204 iterations, equivalent to HELIOS post-processing step. false: 4 iterations, equivalent to HELIOS radiative step done in convective loop. This is slow and mainly kept for HELIOS backward compatibility and debugging.
if true, uses a real spectrum loaded from a file
Path to stellar spectrum file.
Opacity file, containing opacities generated by HELIOS’ ktable generator, converted to SI as default unit.
Use opacity data in input file as CGS units. This accepts the HELIOS ktable output file directly, without unit adaptation.
Diffusivity, also known as
g0 used for case without clouds. For normal gas, should usually be g0 = 0.0
At beginning opf Alfrodull step, when interpolating opacities, for bins below 2/3 of the wavelength bins (bin index < nbin*2/3), it selects between the max of the interpolated opacity from the table and this limit. This effectively sets a minimum opacity for short wavelength. (set to 0.0 in tests)
Experimental/Debug: adds a constant offset to all opacities. To investigate behaviour deep in atmosphere.
true/false: enable scattering computation
true/false: enables scattering correction. If false, uses E=1
true/false: enable clouds from a cloud file.
fcloud factor used for clouds.
Input file for cloud absorption cross sections, scattering cross section and asymmetry parameter.
true/false: store computed w0 and g0 parameters per band. Optional storage, because this increases memory usage tremendously.
true: Use direct beam false: no direct beam. Stellar spectrum is used as diffuse flux in boundary condition at top of atmosphere interface
Angular limit to horizontal bellow which TOA stellar flux is set to 0.
Checks on G± and wiggle mu_star.
Numeric limit on G± before wiggling mu_star
true: apply limit on full G± term (usually value of ~300). false: apply limit on denominator of G± term (usually about 1e-5)
Angle to use to increment acos(mu_star) at each iteration when we hit the G± limit. [degrees]
Max number of iterations to try wiggling mu_star. This means that the max angle change will be (Alf_mu_star_iteration_max*Alf_G_pm_mu_star_increment).
Old G_pm max cap at ± 1e8 from Helios, kept for backward compatibility.
We can ramp up and ramp down Alfrodull (and with similar parameters, Double Gray) with those parameters. If parameter is negative, it is ignored. Qheat is multiplied by a sigmoid function from 0 to full value and from full value to 0 on the range of steps marked by start and stop.
Step at which to start Alf spin up. if -1, starts at full Alf.
Step at which to end Alf spin up. if -1, starts at full Alf.
Step at which to start Alf spin down. if -1, runs at full Alf untill end of simulation.
Step at which to stop Alf spin down. if -1, runs at full Alf untill end of simulation.
compute Alf every nstep instead of every step. Reuses Qheat computed at last active step in between.
Optimisation: run this number of columns computation in parallel. Depends on grid size, number of levels and number of bins. The simulation needs to fit into memory for this to work. If the program gives “out of memory” cuda errors, use a smaller number of columns.
For a simulation with 40 levels, here are some numbers used that fit into memory:
| grid resolution | wavelength resolution | number of parallel columns |
|---|---|---|
| g4 | r5 | 2562 |
| g4 | r50 | 1284 |
| g4 | r500 | 128 |
| g5 | r5 | 1284 |
| g5 | r50 | 1284 |
| g6 | r5 | 512 |
| g6 | r50 | 512 |
| g6 | r500 | 80 |
Print out some debugging information. Mostly G± values