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Experiment 1 (5749 runs)

Similarities between simulations

• Simulations are run in a 2D spherical annulus with StagYY (Tackley 2008, Hernlund & Tackley 2008).

• There are 5749 simulations in this experiment.

• These are saved as: runXXX-2.tgz, where XXX denotes run number.

• Each simulation uses the same Fortran code.

• 'defaults_include.f90' (link) contains all the important default convection parameters, which need to be included in papers etc., but which do not vary between simulations.

• Some of the parameters in defaults_include.f90 are over-written by parameters in the parameter file called 'par'.

• In some cases the tar files contain nested tar files, all of which will need to be extracted.

Differences between simulations

• The parameters that vary between simulations are set in the 'par' file. These are mostly (but maybe not all) labelled '**varies**'

• These parameters are set from the table contained in: VaryingParameters_first5749runs_27Feb14.dat (link).

• Each line lists the varying parameters for one simulation. E.g. line 10 contains all the parameters for simulation 10, saved in run10-2.tgz.

• These parameters are listed below, under Varying parameters.

• Each simulation also uses 3 perplex files HARZXXX_1.tab, MORBXXX_1.tab and PRIMXXX_1.tab that contain the mineral physics data for the three end-member rock types, harzburgite, basalt and primordial. More details are included below under Perple_X

Varying parameters

VaryingParameters_first5749runs_27Feb14.dat contains 5749 lines (number of runs), 30 entries each (the varying parameters). Below are the definitions of the varying parameters written as (column, StagYY parameter name, description, units):

12 of these are set in the 'par' file:

1. Rh: Initial radiogenic heating [W/kg]

2. core_Kppm: Initial core radiogenic potassium concentration [ppm]

3. Dpartition_hpe: Partition coefficient for radioactive tracers upon melting [factor]

4. dHeat_dprim: Radioactive heating enhancement in primordial material with respect to bulk mantle [factor]

5. T0_init: Initial mantle potential temperature [K]

6. botT_val: Initial CMB temperature [K]

7. eta0: Reference viscosity [Pa s]

8. stressY_eta: Surface yield stress [M Pa]

9. deta_primordial: Viscosity contrast between primordial and bulk mantle [factor]

10. V_eta: Viscosity activation volume [m^3]

11. d_primordial: Thickness of primordial material [km] (if = 0, there will still be a PRIMXXX_1.tab file, it is just not used)

12. basalt_frac_ref: Fraction of basalt end-member in mantle [factor]

The following 18 parameters affect Perple_X calculations, but are not set in the 'par' file:

13. MORB Al2O3 mol% for Perple_X calculations

14. MORB CaO

15. MORB FeO

16. MORB MgO

17. MORB Na2O

18. MORB SiO2

19. HARZ Al2O3

20. HARZ CaO

21. HARZ FeO

22. HARZ SiO2

23. HARZ MgO

24. The value of x is a switch for the model choice for primordial composition. If 0<=x<=0.1use MORB + chondrite; if 0.1<x<=0.45 pyrolite + FeO; if 0.45<x<=0.8 MORB; if 0.8<x<=1 no primordial and then parameter 11=0 (in this case a fixed composition is assigned to PRIM, and a file is still generated, but not used by StagYY).

25. PRIM Al2O3

26. PRIM CaO

27. PRIM FeO

28. PRIM MgO

29. PRIM Na2O

30. PRIM SiO2

Perple_X mineral physics information

For details about the Perple_X free energy minimisation package see Connolly (2009). Version Perple_X_6.6.8_OSX_Intel_generic_MC_Feb_24_2013 was used. For a given set of parameters (13-30) this produces ascii look up tables *XXX_1.tab. Not all have identical grids. Each file contains a header. The format of these files and headers is:

• Version

• Table name

• Lowest temperature

• Temperature grid spacing

• Number of temperature grid points

• Lowest pressure (bar)

• Pressure grid spacing

• Number of pressure grid points

• Number of columns

• The columns are: temperature, pressure, density, bulk modulus, shear modulus, enthalpy, and thermal expansivity.

Outputs from the StagYY simulations

• They are stored in the +op directory in each tar file.

• A given time frame is stored as 1 file. There are normally many numerical time steps between each written frame.

• The time between frames may vary significantly.

• Files are numbered sequentially by frame, starting at 0 (the initial condition).

• Number does not refer to age but simulated time does increase with number.

• Format is SimulationNumber_FieldFrame. E.g. 21_t00033 is temperature at frame 33 for simulation 21.

Output fields

• 2D fields (i.e. with a value in each cell)

• Bvel** bulk velocity

• Pvel** P-wave velocity

• Svel** S-wave velocity

• _age time since material last melted (averaged over all tracers in a given cell)

• _bs basalt fraction

• _eta viscosity

• _f melt fraction

• _hpe heat producing element concentration

• _hz harzburgite fraction

• _prm primordial fraction

• _rho density

• _str stress second invariant

• _sx direction of principle stress axis (vector)

• _t temperature

• _vp velocity and pressure (velocity vector plus pressure)

**currently not usable, should be calculated from the Perple_X files *XXX_1.tab given composition, temp and pressure using the attached matlab script ReadStagYY_seismicvelocity.m (link)




• 1D fields (i.e. only along the surface and/or CMB)

• _cr crustal thickness

• _cs CMB and surface topography (not accounting for self gravity)

• _csg CMB and surface topography (accounting for self gravity)

• _g CMB & surface geoid, accounting for self gravity

• _hf heat flux at CMB and surface

• _div divergence of horizontal velocity at surface

• _vor vertical vorticity at surface (=0 in 2D)




• Tracers, each of which holds several quantities

• _tra tracers (often emptied during run to conserve disk space, needed to restart simulation)




• Text files

• _refstat.dat information about radial variation of physical properties in the reference state

• _time.dat various quantities at every time step

• _rprof.dat various radial profiles at every output frame

• _cslm.dat CMB and surface topography in spherical harmonics, self-gravitating

• _glm.dat CMB and surface geoid in spherical harmonics, self-gravitating

Reading binary files

• Binary files can be read using the matlab script ReadStagYY_database.m (link)

• Type 'help ReadStagYY_database' to see what the script does.

• The data are stored as (y,z) matrices (in the script called data_out.*) (y corresponds to 512 cells azimuthally, and z to 64 cells radially), simulation age in seconds at time of writing (data_out.Time), radius of the CMB data_out.RCMB) and a note (data_out.Var).

• The coordinates in [m] of the data fields are radius = data_out.Z(y,z)+data_out.RCMB azimuth = data_out.Y(y,z) * [data_out.Z(y,z)+data_out.RCMB]

The results from our numerical simulations are freely available and can be searched for downloads using the criteria below.