data.exofric

The data.exofric file is used to set parameters for the dragtreatment used in expeRT/MITgcm.

Warning

Previous versions of exorad used to treat friction in the data.exo file. This has changed now!

A typical data.exofric file may look like this:

# FRICTION
# Rayleigh friction prescription to U and V wind field

# EXORAD_FRIC_TYPE:: Type of friction. <1: friction on U and V, >1: friction on geographic U only;
#          0, ABS>3 = no friction
#          +-1      = Carone2020, Schneider2022
#          +-2      = global friction with timescale: EXORAD_FRIC_GLOBAL_TAU
#          +-3      = ohmic drag like Rauscher2013
# EXORAD_FRIC_HEAT  :: True if you want to dissipate the heat, false if you just want the drag
# EXORAD_FRIC_GLOBAL_TAU:: Set a global dragtimescale in seconds (only used when EXORAD_FRIC_TYPE = +-2)
# EXORAD_FRIC_OHM_B:: Magnetic field strength (in Tesla), whenever ohmic dissipation (EXORAD_FRIC_TYPE = +-3) is used
# EXORAD_KF :: sets friction time scale, Unit 1/days-1 (only used when EXORAD_FRIC_TYPE = +-1)
# EXORAD_SIGMA_B :: Sets vertical pressure [Pa] for lower boundary
#                   Defined wrt lower bounary as specified in data (only used when EXORAD_FRIC_TYPE = +-1)
# EXORAD_FRIC_DUMP :: Flag to output or not diagnostics of the rayleigh drag
# EXPRAD_FRIC_MIN_P :: Minimum pressure for friction

&EXORAD_FRIC
     EXORAD_KF = 1.0
     EXORAD_SIGMA_B = 0.7
     EXORAD_FRIC_HEAT = .TRUE.
     EXORAD_FRIC_TYPE = 1
     EXORAD_FRIC_GLOBAL_TAU = 0.0
     EXORAD_FRIC_OHM_B = 0.0005
     EXORAD_FRIC_DUMP = .TRUE.
     EXORAD_deltaT_FRIC = 100.0
     EXORAD_FRIC_MAX = 1.0E-4
     EXORAD_INTERP_STEP_FRIC = 2
     EXORAD_FRIC_MIN_P = 10.0
/

# Elemental data for ohmic dissipation
# Arrays need to be filled up onto EXORAD_OHM_NEL. Change EXORAD_OHM_NEL in EXORAD_IONISATION_DATA.h if requiered.
# EXORAD_OHM_ELABU  :: Elemental abundancies, sorted with proton number
#                        log(eps_X)=log(NX/NH) + 12
#                        see Asplund2009, Table 1, for more information about
#                        the units.
#                        Note: the elemental abundancies will be
#                        automatically converted to NX/NH during readin.
# EXORAD_OHM_POTENTIAL :: first ionisation potential of elements, sorted
#                        with proton number, needs to be in eV, will be converted during readin
&EXORAD_OHM_DATA
     EXORAD_OHM_ELABU = 12.00, 10.93, 1.05, 1.38, 2.70, 8.43, 7.83, 8.69,
                    4.56, 7.93, 6.24, 7.60, 6.45, 7.51, 5.41, 7.12,
                    5.50, 6.40, 5.03, 6.34, 3.15, 4.95, 3.93, 5.64,
                    5.43, 7.50, 4.99, 6.22
     EXORAD_OHM_POTENTIAL = 13.59844, 24.58741, 5.39172, 9.32263,
                    8.29803, 11.2603, 14.53414, 13.61806, 17.42282,
                    21.56454,  5.13908, 7.64624, 5.98577, 8.15169,
                    10.48669, 10.36001, 12.96764, 15.759, 4.34066,
                    6.11316, 6.56144, 6.8282, 6.7462, 6.7665,
                    7.43402, 7.9024, 7.8810, 7.6398

/

The EXORAD_FRIC section is used to control the strength of the boundary layer friction. Parameters are described above. There are four types of friction that can be applied to the model.

The EXORAD_OHM_DATA section is used to set abundancies and ionisation potentials for ohmic dissipation.

Warning

Ohmic dissipation is tested. However, please mind that there are no results yet published using the ohmic dissipation treatment outlined here.