Data Tables Buhler Piqueux JGR 2021

We have provided data tables for figures 3-6 and model routines used in Buhler and Piqueux (2021), JGR.

Figures 3 and 6

We have provided ten data tables: as_zreg.txt, matm.txt, mcap.txt, mreg.txt, matm_hist.txt, mcap_hist.txt, mreg_hist.txt, obl.txt, obl_hist.txt, and t_hist.txt. These tables contain the information shown in Fig. 3 and Fig. 6 in the text.

as_zreg.txt is a 1-dimensional array of length 7 that contains the product of the specific surface area and regolith thickness z_reg used in each of the seven model outputs, corresponding to the caption in Fig. 3 and Fig. 6.

The data for Fig 3 is contained in: matm.txt, mcap.txt, mreg.txt, and obl.txt.

obl.txt is a 1-dimensional array of length 91, spanning 0 to 90, that contains obliquity values in degrees.

matm.txt, mcap.txt, and mreg.txt are each 2-dimensional arrays of shape (7, 91) that provide our model output solution for atmosphere mass (matm.txt), cap mass (mcap.txt), and adsorbed CO₂ mass (mreg.txt) in kilograms as a function of obliquity (along the axis of length 91; corresponding to obl.txt) and regolith thickness (along the axis of length 7; corresponding to zreg.txt). All values were calculated assuming regolith thermal conductivity k_reg = 1.0 W m^-1 K^-1 and regolith albedo A_reg = 0.25.

The data for Fig. 6 is contained in: matm_hist.txt, mcap_hist.txt, mreg_hist.txt, obl_hist.txt, and t_hist.txt.

t_hist.txt is a 1-dimensional array of length 1000 with values of time referenced to J2000 in units of 1000 years.

obl_hist.txt is a 1-dimensional array of length 1000 with values of obliquity in units of degrees from Laskar et al. (2004).

matm_hist.txt, mcap_hist.txt, and mreg_hist.txt are each 2-dimensional arrays of shape (7, 1000) that provide our model output solution for atmosphere mass (matm.txt), cap mass (mcap.txt), and adsorbed CO₂ mass (mreg.txt) in kilograms as a function of time (along the axis of length 1000; corresponding to t_hist.txt) and regolith thickness (along the axis of length 7; corresponding to as_zreg.txt). All values were calculated assuming regolith thermal conductivity k_reg = 1.0 W m^-1 K^-1 and regolith albedo A_reg = 0.25.

Figure 4

MCMC_chains.txt is a table of size 3 x 1e7. The axis of length 1e7 correspond to steps in the MCMC simulation. Values in the first row are the regolith thermal conductivity (k; W m^-1 K^-1) value, values in the second row are the regolith thickness (z_reg; m) value, and values in the third row are the regolith specific surface area (a_S; m² kg^-1) value at each timestep.

Figure 5

mtothistx.txt is a table of size 1 x 100 containing the bin value total obliquity-timescale exchangeable inventory (kg).

mtothisty_norm is a table of size 1 x 100 containing the normalized probability density (unitless) for the corresponding mass bin index.

Figure 7

Figure 7 comprises an ensemble of 5e6 draws of model results for MCID bounding layer elevations and total obliquity-timescale exchangeable CO2 reservoirs taken from the model input parameter probability distributions shown in Figure 4.

elevs0.txt is a table of size 1 x 5e6 containing the fraction of the MCID modeled to be below the topmost bounding layer of water ice (unitless).

elevs1.txt is a table of size 1 x 5e6 containing the fraction of the MCID modeled to be below the second topmost bounding layer of water ice.

elevs2.txt is a table of size 1 x 5e6 containing the fraction of the MCID modeled to be below the third topmost bounding layer of water ice.

elevs3.txt is a table of size 1 x 5e6 containing the fraction of the MCID modeled to be below the bottommost bounding layer of water ice.

mtots.txt is a table of size 1 x 5e6 containing the total obliquity-timescale exchangeable CO2 reservoir corresponding to elevation indices in elevs0.txt, elevs1.txt, elevs2.txt, and elevs3.txt.

Model Routines

Construct Subsurface Temperature Arrays.py is a 1d thermal diffusion model that constructs subsurface temperature arrays as a function of latitude, depth, and insolation (based on orbit parameters) in sub-sol time steps.

Construct mean annual subsurface arrays_v0.3.py creates the mean annual subsurface profile from the output of Construct Subsurface Temperature Arrays.py for more efficient calculation in Pressure_reg_only_iterator_v8.py.

Pressure_reg_only_iterator_v8.py is a joint atmosphere-regolith equilibration model (without a CO2 ice cap) that calculates the atmospheric pressure in equilibrium with a regolith of given defined properties as a function of orbit parameters, using as input the mean annual temperature profiles output from Construct Subsurface Temperature Arrays.py. These equilibrium solutions are an input that improves numerical stability for Pressure_MCID_reg_iterator_v8.py.

Pressure_MCID_reg_iterator_v8.py is the full joint cap-atmosphere-regolith equilibration model that calculates the equilibrium atmospheric pressure, cap mass, and adsorbed CO2 as a function of orbit parameters, using as input the mean annual temperature profiles output from Construct Subsurface Temperature Arrays.py and regolith-atmosphere equilibrium solutions from Pressure_reg_only_iterator_v8.py. The difference in cap mass at each of the previous obliquity maxima can then be used to find the model-predicted layer thicknesses of the MCID as input to MCMC.py.

MCMC.py is the Markov Chain Monte Carlo model that compares modeled stratigraphy to the observed stratigraphy of the MCID.

References

Laskar, J., Correia, A.C.M., Gastineau, M., Joutel, F., Levrard, B., Robutel, P., 2004. Long term evolution and chaotic diffusion of the insolation quantities of Mars. Icarus 170, 343–364