CESM2.1.5 POP2.0 Namelist Definitions

Tracer advection choice.

Valid Values: 'center','upwind','lw_lim'
Default: 'upwind3'

Flag to prevent very cold water.

Default: .false.

Check for convergence every convergenceCheckFreq iterations.

Default: 10

Start checking for convergence after convergenceCheckStart steps 
(starting step number of convergence checking).

Default: 60

Convergence error criterion: |δX/X| < convergenceCriterion

Default: 1.0e-13

Convergence error criterion for Lanczos step.

Default:  0.15

Upper limit on number of solver iterations.

Default: 1000

Maximum number of Lanczos steps taken to get eigenvalues.

Default: 100

Preconditioner choice.
Valid Values: 'diagonal', 'evp','file'
'diagonal' -- No preconditioner.
'file'     -- A preconditioner is used to reduce number of iterations to convergence.  No longer supported.
'evp'      -- Edge-vertex preconditioner.

Default: 'diagonal'

File containing preconditioner coefficients for solver; 
used when preconditionerChoice='file'.

Default: 'unknownPrecondFile'

Method to solve the two-dimensional elliptic equation for the surface pressure.

Valid Values: 'ChronGear','pcg','PCSI'
'ChronGear' = Chronopoulos-Gear conjugate-gradient solver with preconditioner.
'pcg'       =  Preconditioned conjugate-gradient solver.
'PCSI'      = Preconditioned Classical Stiefel Iteration.

Default: 'ChronGear'

Flag to run POP in bit-for-bit mode.

Default: .false.

Flag to run pop in the CESM context.

Default: .true.

Flag to run POP with code that is bit-for-bit with the ccsm4 control run. (According to source notes, this option should have been removed in ccsm4_0_1!).

Default: .false.

Flag for whether POP is coupled to another system.

Default: .true.

If this is true, then various internal consistency checks are enabled.

Default: DEBUG from env_run.xml, but overridable by user_nl_pop

Frequency POP is coupled to atmosphere / sea ice models via CESM flux coupler (units given by coupled_freq_opt).

Default:  24

Units of time for coupled_freq (frequency POP is coupled to atmosphere/sea ice models
via CESM flux coupler).

Valid Values: 'nyear', 'nmonth', 'nday', 'nhour', 'nsecond', 'nstep', 'never'
Default: 'nhour'

Option for distributing net shortwave heat flux over a coupling interval (all options preserve time-integrated flux).

Valid Values: 'const','12hr','cosz'
Default: 'cosz'

Flag to damp UVEL and VVEL; currently the only method for damping is from private communication with Nick Klingaman (Univ. of Reading); it is a non-linear damping.

Default: .false.

Flag to control the computation and printing of barotropic stream function diagnostics.

Default: .true.

Flag to control the computation of global budget diagnostics for tracers.

Default: .true.

Flag to control the printing Robert-filter budget terms in a human-eye-friendly manner. 

Default: .false.

Beginning latitude for the auxiliary grid (degrees north).

Default: -90.0

Ending latitude for the auxiliary grid (degrees north).

Default:  90.0

Type of the auxiliary latitudinal grid.

Valid Values: 'southern', 'full', 'user-specified'
Default: 'southern'

Flag for turning on output for meridional overturning circulation.

Default: .true. for displaced pole grids, .false. for tripole grids.

Flag for outputting northward heat transport.

Default: .true. for displaced pole grids, .false. for tripole grids.

Auxiliary grid dimension.

Default: 180

Flag for outputting northward salt transport.

Default: .true. for displaced pole grids, .false. for tripole grids.

Number of regions for all transport diagnostics.

Default: 2

Names of the selected input regions when n_transport_reg = 2.

Default: 'Atlantic Ocean','Mediterranean Sea','Labrador Sea','GIN Sea','Arctic Ocean','Hudson Bay'

Selector for method used to distribute blocks in baroclinic distribution.

Valid Values: 'cartesian', 'balanced', 'spacecurve', 'blockone'
Default: 'cartesian'

Selector for type of boundary used in the logical east-west direction for global domain.

Valid Values: 'cyclic', 'closed'
Default: 'cyclic'

Number of processors in the baroclinic distribution.

Default: Set by CESM scripts

Number of processors in the barotropic distribution.

Default: Set by CESM scripts

Selector for type of boundary used in the logical north-south direction for global domain. 

Valid Values: 'cyclic', 'closed', 'tripole'
Default: 'closed'

Flag to add MPI_Barrier calls for timing studies in time-step module.

Default: .false.

Selector for method used to distribute blocks in barotropic distribution.

Valid Values: 'cartesian', 'balanced', 'spacecurve', 'blockone'
Default: 'cartesian'

Default: CCSM_CO2_PPMV value in env_run.xml

Default:

Default:

Default: 'base model'

Default: .true.

Default: 'marbl_in' for single instance, 'marbl_in_####' for multi-instance.

Default:

Default: 'nc'

Default:

Default:

Default:

Default:

Default:

Default: ecosys_jan_IC_gx3v7_20180308.nc or ecosys_jan_IC_gx1v6_20180308.nc (none provided for tripole grids)

Default: 'nc'

Default: 'ccsm_RUNTYPE'

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Which equation of state to use.

Valid Values: 'jmcd', 'mwjf', 'poly', 'line'
Default: 'mwjf'

File containing polynomial equation of state coefficients.

Default: 'internal'

Frequency (in steps) for checking validity of temperature and salinity ranges.

Default: 100000

Option for checking for valid temperature and salinity ranges.

Valid Values: 'ignore', 'check', 'enforce'
Default: 'enforce'

Default: none

Default: none

Default: none

Default: auto-filled by CESM scripts

Default: none

Default: none

Default: none

Default: none

Ratio of lower-layer depth to H at estuary mouth.

Default: none

Thickness (m) of lower layer of exchange flow.

Default: none

Thickness (m) of upper layer of exchange flow. 

Default: none

Default: none

Default: none

Increment (in hours) between forcing times if ap_data_type='n-hour'.

Default: 1.e20

Renormalization constants for the components in the atmospheric pressure forcing file.

Default: 20*1.

Type or periodicity of atmospheric forcing.

Valid Values: 'none', 'analytic', 'annual', 'monthly', 'monthly-equal', 'monthly-calendar', 'n-hour'
Default: 'none'

ap_filename format (binary or netCDF)

Valid Values: 'bin', 'nc'
Default: 'bin'

Name of file containing atmospheric pressure forcing, or root of filenames if ap_data_type='n-hour'.

Default: 'unknown-ap'

How often to temporally interpolate atmospheric forcing data to current time.

Valid Values: 'never','n-hour','every-timestep'
Default: 'never'

Increment (in hours) between interpolation times if ap_interp_freq = 'n-hour'.

Default: 1e20

Type of temporal interpolation for atmospheric pressure forcing data.

Valid Values: 'nearest', 'linear', '4point'
Default: 'nearest'

Default: CCSM_CO2_PPMV value in env_run.xml

Default: 'const'

Default: CCSM_CO2_PPMV value in env_run.xml

Default: depends on OCN_CO2_TYPE in env_run.xml

Default:

Default:

Default:

Default:

Default:

Default:

Year in atm data that corresponds to ciso_atm_model_year.

Default: 1

Arbitrary model year.

Default: 1

Default: none provided

Default: 'nc'

Default: 'DSTSF'

Default: dst79gnx_gx3v7_20100305.nc or dst79gnx_gx1v6_090416.nc

Default: 1.0e-1

Default: 'driver'

coarse/fine dust ratio threshold, used in iron_flux_source=='driver-derived' computation

Default: 55.0

used in iron_flux_source=='driver-derived' computation

Default: 170.0

used in iron_flux_source=='driver-derived' computation

Default: 0.01

Default: none provided

Default: 'nc'

Default: 'FESEDFLUXIN'

Default: fesedflux_gx3v7_cesm1_97_2017.nc or fesedfluxTot_gx1v6_cesm2_2018_c180618.nc

Default: 1.1574e-6

Default: none provided

Default: 'nc'

Default: 'FESEDFLUXIN'

Default: feventflux_gx3v7_5gmol_cesm1_97_2017.nc or feventflux_gx1v6_5gmol_cesm1_97_2017.nc

Default: 1.1574e-6

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Default: 'drv'

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Default: none provided

Default: 'nc'

Default: 'DSTSF'

Default: solFe_scenario4_current_gx3v7_6gmol_cesm1_93_20161122.nc or solFe_scenario4_current_gx1v6_8gmol_cesm1_93_20161114.nc

Default: 1.79e6

Default: 'driver-derived'

fraction, by weight, of iron in black carbon from atm

Default: 0.06

fraction, by weight, of iron in coarse dust from atm

Default: 0.035

fraction, by weight, of iron in fine dust from atm

Default: 0.035

fraction, by weight, of iron in black carbon from seaice

Default: 0.06

fraction, by weight, of iron in dust from seaice

Default: 0.035

Default: none provided

Default: none provided

When turned on, ocn.ecosys.tavg.csh will accumulate ALL ecosys diagnostics

When turned on, ocn.ecosys.tavg.csh will output alt_co2 related fields

If .false., abort if the coupler passes NHx or NOy and ndep_data_type is not 'driver'

Default: .false.

Default: none provided

Default: 'monthly-calendar' or 'shr_stream'

Default: depends on grid and OCN_TRANSIENT

Default: 7.1429e6

Default: 1849 for OCN_TRANSIENT=1850-2000, 2004 for rcp runs, 2014 for ssp runs,
2039 for ssp534, 0 for OCN_TRANSIENT=CORE2OMIP,JRA_OMIP

Default: 1849 for OCN_TRANSIENT=1850-2000, 2004 for rcp runs, 2014 for ssp runs,
2039 for ssp534, 1637 for OCN_TRANSIENT=CORE2OMIP, 1652 for OCN_TRANSIENT=JRA_OMIP

Default: 2006 for OCN_TRANSIENT=1850-2000, 2101 for rcp and ssp runs,
2010 for OCN_TRANSIENT=CORE2OMIP, 2019 for OCN_TRANSIENT=JRA_OMIP

Default: none provided

Default: 'nc'

Default: 'NHx_deposition'

Default: ndep_ocn_1850_w_nhx_emis_gx3v7_c180803.nc or ndep_ocn_1850_w_nhx_emis_gx1v6_c180803.nc

Default: 7.1429e6

Default: none provided

Default: 'nc'

Default: 'NOy_deposition'

Default: ndep_ocn_1850_w_nhx_emis_gx3v7_c180803.nc or ndep_ocn_1850_w_nhx_emis_gx1v6_c180803.nc

Default: 7.1429e6

constant for o2_consumption_scalef_opt=const
Default: 1.0

Default: none provided

Default: 'nc'

Default: 'o2_consumption_scalef'

Default: 
o2_consumption_scalef_0.30_POP_gx1v6_20180623.nc (gx1v6,gx1v7)

Default: 1.0

option for specification of o2_consumption_scalef

Valid Values: 'const', 'file_time_invariant'
Default: 'const'
'file_time_invariant' (gx1v6,gx1v7) for OCN_COUPLING='full'

constant for p_remin_scalef_opt=const
Default: 1.0

Default: none provided

Default: 'nc'

Default: 'p_remin_scalef'

Default: none provided

Default: 1.0

option for specification of p_remin_scalef

Valid Values: 'const', 'file_time_invariant'
Default: 'const'

Default: 'PO4','NO3','SiO3','O2','ALK'

Default: 'PO4','NO3','SiO3','O2','ALK'

Default: none provided, constructed by build-namelist

Default: ecosys_restore_POP_gx3v7_20170113.nc (gx3v7), ecosys_restore_POP_gx1v6_20170113.nc (gx1v6,gx1v7)

Default: 0.0

Default: none provided

Default: 'nc'

Default: 'RESTORE_INV_TAU_MARGINAL_SEA_ONLY'

Default: ecosys_restore_inv_tau_POP_gx3v7_20170125.nc (gx3v7), ecosys_restore_inv_tau_POP_gx1v6_20170125.nc (gx1v6,gx1v7)

Default: 1.0

Default: 'file_time_invariant' for gx3v7, gx1v6, gx1v7 grids, 'const' otherwise

Default: 'alk_riv_flux'

Default: 1.0

Default: 'dfe_riv_flux'

Default: 1.0

Default: 'dic_riv_flux'

Default: 1.0

Default: 'din_riv_flux'

Default: 1.0

Default: 'dip_riv_flux'

Default: 1.0

Default: 'doc_riv_flux'

Default: 1.0

Default: 'don_riv_flux'

Default: 1.0

Default: 'dop_riv_flux'

Default: 1.0

Default: 'dsi_riv_flux'

Default: 1.0

Default: riv_nut.gnews_gnm.gx3v7_nnsm_e1000r500.20170425.nc (gx3v7),
riv_nut.gnews_gnm.gx1v7_nnsm_e1000r300.20170425.nc (gx1v6,gx1v7)
riv_nut.gnews_gnm.gx3v7_nn_open_ocean_nnsm_e1000r500_marginal_sea.20170425.nc (gx3v7,estuary_type='vsf_ebm'),
riv_nut.gnews_gnm.gx1v7_nn_open_ocean_nnsm_e1000r300_marginal_sea.20170425.nc (gx1v6,gx1v7,estuary_type='vsf_ebm')
riv_nut.gnews_gnm.rx1_to_gx1v7_nn_open_ocean_nnsm_e1000r300_marginal_sea_170413.20190602.nc (gx1v6,gx1v7,estuary_type='vsf_ebm',rof_grid='rx1')
riv_nut.gnews_gnm.JRA025m_to_gx1v7_nn_open_ocean_nnsm_e1000r300_marginal_sea_190214.20190602.nc (gx1v6,gx1v7,estuary_type='vsf_ebm',rof_grid='JRA025')

Default: 263 for OCN_TRANSIENT=CORE2_OMIP, 248 for OCN_TRANSIENT=JRA_OMIP, 1900 otherwise

Default: 1900

Default: 1900 for OCN_TRANSIENT=unset,CORE2,JRA, 2000 otherwise

Default: 2225.0

Default: 1944.0

Default: 1944.0

Default: 1944.0

Option for geothermal (bottom) heat flux.

Valid Values: 'const', 'spatial'
Default: 'const'

Constant geothermal heat flux to apply to bottom layers. (W/m^2)

Default: 0.0

Depth (cm) below which geothermal heat flux is applied.

Default: 1000.0e2

Increment (hours) between forcing times if pt_interior_data_type='n-hour'.

LANL Default: 1e20
CESM Default: 24

Renormalization constants for components in interior potential temperature forcing file.

Default: 20*1.

Type or periodicity of interior potential temperature forcing.

Valid Values: 'none', 'annual', 'monthly', 'monthly-equal', 'monthly-calendar', 'n-hour', 'shr_stream'
Default: 'none'

pt_interior_filename format (binary or netCDF).

Valid Values: 'bin', 'nc'
Default: 'bin'

File containing interior potential temperature data, or root of filenames if pt_interior_data_type='n--hour'.

Default: 'unknown-pt_interior'

Interior potential temperature formulation.

Default: 'restoring'

How often to temporally interpolate interior potential temperature data to current time.

Valid Values: 'never', 'n-hour', 'every-timestep'
LANL Default: 'never'
CESM Default: 'every-timestep'

Increment (hours) between interpolation times if interp_freq='n-hour'

LANL Default: 1e20
CESM Default: 72

Type of temporal interpolation for interior potential temperature data.

Valid Values: 'nearest', 'linear', '4point'
LANL Default: 'nearest'
CESM Default: 'linear'

pt_interior_restore_filename format (binary or netCDF).

Valid Values: 'bin', 'nc'
Default: 'bin'

Name of file containing variable interior potential temperature restoring data.

Default: 'unknown-pt_interior_restore'

Maximum level for interior potential temperature restoring.

Default: 0

Restoring timescale (days) if pt_interior_formulation='restoring'.

LANL Default: 1e20
CESM Default: 365

Default: unknown-pt_interior_shr_stream

Default: 1

Default: 1

Default: 1

PT interior restoring includes the surface layer

Default: .false.

Enable variable interior potential temperature restoring.

Default: .false.

Increment (hours) between forcing times if s_interior_data_type='n-hour'.

LANL Default: 1e20
CESM Default: 24

Renormalization constants for components in interior salinity forcing file.

Default: 20*1.

Type or periodicity of interior salinity forcing.

Valid Values: 'none', 'annual' ,'monthly', 'monthly-equal', 'monthly-calendar', 'n-hour', 'shr_stream'
Default: 'none'

s_interior_filename format (binary or netCDF)

Valid Values: 'bin', 'nc'
Default: 'bin'

Name of file containing interior salinity data, or root of filenames if s_interior_data_type='n-hour'.

Default: 'unknown-s_interior'

Interior salinity formulation.

Default: 'restoring'

How often to temporally interpolate interior salinity data to current time.

Valid Values: 'never', 'n-hour', 'every-timestep'
LANL Default: 'never'
CESM Default: 'every-timestep'

Increment (hours) between interpolation times if s_interior_interp_freq='n-hour'.

LANL Default: 1e20
CESM Default: 72

Type of temporal interpolation for interior salinity data.

Valid Values: 'nearest', 'linear', '4point'
LANL Default: 'nearest'
CESM Default: 'linear'

s_interior_restore_filename format (binary or netCDF).

Valid Values: 'bin', 'nc'
Default: 'bin'

Name of file containing variable interior salinity restoring data.

Default: 'unknown-s_interior_restore'

Maximum level for interior salinity restoring.

Default: 0

Restoring timescale (days) if s_interior_formulation='restoring'.

LANL Default: 1e20
CESM Default: 365

Default: unknown-s_interior_shr_stream

Default: 1

Default: 1

Default: 1

S interior restoring includes the surface layer

Default: .false.

Enable variable interior salinity restoring.

Default: .false.

Adjust precipitation to balance water budget.

LANL Default: .false.
CESM Default: .true. if sfwf_formulation='partially-coupled', .false. otherwise

Treat fresh water flux as virtual salt flux when using varthick sfc layer.

LANL Default: .false.
CESM Default: .true.

Balance E, P, M, R, and S in marginal seas.

LANL Default: N/A, CESM only
CESM Default: .true. if sfwf_formulation='partially-coupled', .false. otherwise

Flag for sending precip_fact to CESM coupler for use in fresh-water balance.

LANL Default: N/A, CESM only
CESM Default: .true. if sfwf_formulation='partially-coupled', .false. otherwise

Value used for precip_fact when ladjust_precip=.false..

LANL Default: N/A, CESM only
CESM Default: 1.0

Increment (hours) between forcing times if sfwf_data_type='n-hour'.

LANL Default: 1e20
CESM Default: 24.

Renormalization constants for components in sfwf forcing file.

LANL Default: 20*1.
CESM Default: 0.001, 19*1.

Type or periodicity of surface fresh water flux forcing.

Valid Values: 'none', 'analytic', 'annual', 'monthly', 'monthly-equal', 'monthly-calendar', 'n-hour'
LANL Default: 'analytic'
CESM Default: 'none' or 'monthly'

sfwf_filename format (binary or netCDF).

Valid Values: 'bin', 'nc'
Default: 'bin'

Name of file containing surface fresh water flux data, or root of filenames if sfwf_data_type='n-hour'.

LANL Default: 'unknown_sfwf'
CESM Default: '$sfwf_filename', auto-filled by CESM scripts

Surface fresh water flux formulation.

Valid Values: 'restoring', 'bulk-NCEP', 'partially-coupled'
LANL Default: 'restoring'
CESM Default: 'restoring' or 'partially-coupled', depending on configuration

How often to temporally interpolate surface fresh water flux data to current time.

Valid Values: 'never', 'n-hour', 'every-timestep'
LANL Default: 'never'
CESM Default: 'every-timestep'

Increment (hours) between interpolation times if sfwf_interp_freq='n-hour'.

LANL Default: 1e20
CESM Default: 72.

Type of temporal interpolation for surface fresh water flux data.

Valid Values: 'nearest', 'linear', '4point'
LANL Default: 'nearest'
CESM Default: 'linear'

Restoring timescale (days) if sfwf_formulation='restoring'.

LANL Default: 1e20
CESM Default: 30.

Restoring flux for strong restoring in 'bulk-NCEP' and 'partially-coupled' formulation.

LANL Default: 0.6648
CESM Default: 0.0

Restoring flux for strong restoring over marginal seas in CESM 'bulk-NCEP' and 'partially-coupled' formulations.

LANL Default: N/A, CESM only
CESM Default: 0.6648

Restoring flux for weak restoring in 'bulk-NCEP' and 'partially-coupled' formulation.

LANL Default: 0.092
CESM Default: 0.0115

Flag to control use of fractional ice coverage.

LANL Default: N/A, CESM only
CESM Default: .true. if shf_formulation='partially-coupled', .false. otherwise

Increment (in hours) between forcing times if shf_data_type='n-hour'.

LANL Default: 1e20
CESM Default: 24.

Renormalization constants for the components in the surface heat flux forcing file.

LANL Default: 20*1.
CESM Default: (0.94, 19*1.)

Type or periodicity of surface heat flux forcing.

Valid Values='none', 'analytic', 'annual', 'monthly', 'monthly-equal', 'monthly-calendar', 'n-hour'
LANL Default: 'analytic'
CESM Default: 'monthly' if formulation is 'partially-coupled', 'none' otherwise

shf_filename format (binary or netCDF)

Valid Values: 'bin', 'nc'
Default: 'bin'

Name of file containing surface heat flux data, or root of filenames if shf_data_type='n-hour'.

LANL Default: 'unknown-shf'
CESM Default: '$shf_filename', auto-filled by CESM scripts

Surface heat flux formation.

Valid Values: 'restoring', 'Barnier-restoring', 'bulk-NCEP', 'partially-coupled'
LANL Default: 'restoring'
CESM Default: 'partially-coupled' or 'restoring' depending on configuration

How often to temporally interpolate surface heat flux data to current time.

Valid Values: 'never', 'n-hour', 'every-timestep'
LANL Default: 'never'
CESM Default: 'every-timestep'

Increment (in hours) between interpolation times if shf_interp_freq = 'n-hour'.

LANL Default: 1e20
CESM Default: 72.

Type of temporal interpolation for surface heat flux data.

LANL Default: 'nearest'
CESM Default: 'linear'

Restoring timescale (days) if shf_formulation='restoring'.

LANL Default: 1e20
CESM Default: 30.

Restoring flux for strong restoring in bulk-NCEP

LANL Default: 92.64
CESM Default: 0.0

Restoring flux for strong restoring over marginal seas in bulk-NCEP

LANL Default: N/A, CESM only
CESM Default: 92.64

Restoring flux for weak restoring in bulk-NCEP

Default: 0.

Increment (in hours) between forcing times if ws_data_type='nhour'.

LANL Default: 1e20
CESM Default: 24.

Renormalization constants for the components in the wind stress forcing file.

LANL Default: 20*1.
CESM Default: 10., 19*1.

Type or periodicity of wind stress forcing.

Valid Values: 'none', 'analytic', 'annual', 'monthly', 'monthly-calendar', 'monthly-equal', 'n-hour'
LANL Default: 'analytic'
CESM Default: 'none'

ws_filename format (binary of netCDF)

Valid Values: 'bin', 'nc'
Default: 'bin'

Name of file containing wind stress, or root of filenames if ws_data_type='n-hour'

Default: 'unknown-ws'

How often to temporally interpolate wind stress data to current time; value in namelist is ignored and value set to 'never' if ws_data_type is 'analytic', 'none', or 'annual'.

Valid Values: 'never', 'n-hour', 'every-timestep'
LANL Default: 'never'
CESM Default: 'every-timestep'

Increment (in hours) between interpolation times if ws_interp_freq = 'n-hour'.
LANL Default: 1e20
CESM Default: 72.

Type of temporal interpolation for wind stress data.

Valid Values: 'nearest', 'linear', '4point'
LANL Default: 'nearest'
CESM Default: 'linear'

Name of an input file containing bathymetry information.

Default: 'unknown_bathymetry'

Input file containing thickness (cm) of partial bottom cell for each column.

Default: 'unknown_bottom_cell'

Flag used to select flat-bottom topography.

Default: .false.

Name of the input file (with path) containing horizontal grid information.

Default: Set by CESM scripts based on ocean grid

Option to define the horizontal grid by reading from an input file ('file') or
generating the grid internally ('internal')

Valid Values: 'internal', 'file'
Default: 'file'

Minimum allowable non-zero KMT value.

Default: 3

Flag to run POP in 1D dynamics mode (recommend only using with T62_g37 resolution)

Default: .false.

Flag for removing isolated or disconnected ocean gridpoints.

Default: .false.

Number of topography smoothing passes.

Default: 0

Flag to activate the use of partial bottom cells.

Default: .false.

Name of the input file containing integer region identification numbers at each gridpoint. 

The information in this file associates region ids with a region name; a negative region id 
indicates a marginal sea.

Default: Set by CESM scripts based on ocean grid

Name of the input file containing integer region number at each horizontal gridpoint. 

Default: Set by CESM scripts based on ocean grid

Option for surface layer type: variable thickness ('varthick'), rigid lid ('rigid'),
or old free-surface formulation ('oldfree'). The 'oldfree' option is obsolete.

Valid Values: 'varthick', 'rigid', 'oldfree'
Default: 'varthick'

Name of the input file containing integer indices of the deepest vertical grid
level at each horizontal gridpoint.

Default: Set by CESM scripts based on ocean grid

Option to define the bottom topography (KMT) by reading discretized values from an input file ('file') or
generating an idealized flat-bottom topography internally ('internal').

Valid Values: 'bathymetry','file','internal'
Default: 'file'

Name of the output file for writing horizontal grid information.

Default: '$RUNDIR/$CASENAME.pop.h.topography_bathymetry.ieeer8'

Name of the input file (with path) containing
the thickness (cm) of each vertical layer.

Default: Set by CESM scripts based on ocean grid

Option to define the vertical grid by reading from an input file ('file') or
generating the grid internally ('internal').

Valid Values: 'internal', 'file'
Default: 'file'

If lmin_Coriolis = .true., this is smallest value for Coriolis parameter.
(units = 1/s)

Default: 6.4e-6 (corresponds to ~2.5 degrees)

If lconst_Coriolis = .true., use this value for Coriolis parameter.
(units = 1/s)

Default: 1e-4

If lidentical_columns = .true., use this value for SHF coefficient in surface
forcing (units = W/m^2, converted in source code).

Default: -100

If lidentical_columns = .true., use this value for tau_x in surface forcing.
(units = N/m^2, converted in source code)

Default: 0.1

Flag to run POP with a spatially-constant Coriolis parameter; can not be run
without l1Ddyn = .true.

Default: .false.

Flag to treat all columns the same (true 1D run). Recommend only using with
the T62_g37 resolution; can not be run without l1Ddyn = .true.

Default: .false.

Flag to run POP with a specified minimum value for the Coriolis parameter; can not be run
without l1Ddyn = .true.

Default: .false. if l1Ddyn = .false; .true. if l1Ddyn = .true.

Filename for choosing fields for output in movie file.

Default: Set by CESM scripts based on ocean grid

Data format type of movie_outfile file; either binary ('bin') or netCDF ('nc').

Valid Values: 'bin', 'nc'
Default: 'nc'

Frequency of writing movie files.

Default: 1

Units of time for movie_freq (frequency of writing movie files).

Valid Values: 'never', 'nyear', 'nmonth', 'nday', 'nhour', 'nsecond', 'nstep'
Default: 'never'

Root filename for movie files.

Default: '$CASENAME.pop.hm'

Filename for choosing fields for output in history file.

Default: Set by CESM scripts based on ocean grid

Data format type of history_outfile file; either binary ('bin') or netCDF ('nc').

Valid Values: 'bin', 'nc'
Default: 'nc'

Frequency of writing history files.

Default: 1

Units of time for history_freq (frequency of writing history files).

Valid Values: 'never', 'nyear', 'nmonth', 'nday', 'nhour', 'nsecond', 'nstep'
Default: 'never'

Root filename for history files.

Default: '$CASENAME.pop.hs'

Default: .false. .false. .false.

Default: .false.

Default: .true.

Default: .false. .false. .false.

Default: .true.

Default: 3

Default: ' '

Default: 1 1 1

Default: 'nmonth' 'nmonth' 'once'

Default: 'nc' 'nc' 'nc'

Default: 'nc' 'nc' 'nc'

Default: 1 1 1

Default: 'nmonth' 'nday' 'once'

Default: ' '

Default: 2 2 2

Default: 1 1 1

Default: 1 1 1

Default: ' '

Default: 0 0 0

Default: 'nstep' 'nstep' 'nstep'

Default: 'nmonth1' 'nday1' 'once'

Type of horizontal momentum mixing.

Valid Values: 'del2', 'del4', 'anis', 'gent'
Default: 'anis'

Type of horizontal tracer mixing.

Valid Values: 'del2','del4','gent','gmaniso'
Default: 'gent'

Flag for submesoscale mixing.

Default: .true.

Dimensionless Smagorinksi coefficient parallel to alignment direction.

Default: 8.0

Dimensionless Smagorinksi coefficient perpendicular to alignment direction.

Default: 8.0

Direction that breaks isotropy.

Valid Values: 'flow', 'east', 'grid'
Default: 'east'

Flag to use nonlinear Smagorinski viscosities (c_para/perp and u_para/perp) rather than input anisotropic viscosities (visc_para/perp).

Default: .false.

Flag to allow spatially variable anisotropic viscosity.

Default: .true.

Latitude at which to vary perpendicular Smagorinsky viscosity.

Default: 20.0

Coefficient of latitude-dependent Smagorinsky viscosity.

Default: 0.98

Gaussian width of latitude-dependent Smagorinksy viscosity.

Default: 98.0

Velocity for grid Reynolds number viscous limit (parallel to alignment direction).

Default: 5.0

Velocity for grid Reynolds number viscous limit (perpendicular to alignment direction).

Default: 5.0

File name for variable viscosity factor.

Default: 'ccsm-internal'

var_viscosity_infile format (binary or netCDF).

Valid Values: 'bin', 'nc'
Default: 'bin'

File for output of internally-computed viscosity.

Default: '$RUNDIR/$CASENAME.pop.hv'

var_viscosity_outfile format (binary or netCDF).

Valid Values: 'bin', 'nc'
Default: 'nc'

1 of 7 coefficients for variable viscosity form. Units are cm^2/s.

Default: 0.6e7

1 of 7 coefficients for variable viscosity form.

Default: 0.5

1 of 7 coefficients for variable viscosity form.

Default: 0.16

1 of 7 coefficients for variable viscosity form. Units are 1/cm.

Default: 2.e-8

1 of 7 coefficients for variable viscosity form.

Default: 3

1 of 7 coefficients for variable viscosity form. Units are cm^2/s.

Default: 0.6e7

1 of 7 coefficients for variable viscosity form. Units are degrees of latitude.

Default: 45.0

Viscosity parallel to alignment direction.

Default: 50.0e7

Viscosity perpendicular to alignment direction.

Default: 50.0e7

Horizontal tracer mixing coefficient.

Default: 0.6e7
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Flag to internally compute mixing coefficient.

Default: .false.
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Flag to enable spatially-varying mixing.

Default: .false.
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Horizontal momentum mixing coefficient.

Default: 0.5e8
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Flag to internally compute mixing coefficient.

Default: .false.
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Flag to enable spatially-varying mixing.

Default: .false.
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Horizontal tracer mixing coefficient.

Default: -0.2e20
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Flag to internally compute mixing coefficient.

Default: .false.
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Flag to enable spatially-varying mixing.

Default: .false.
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Horizontal momentum mixing coefficient.

Default: -0.6e20
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Flag to internally compute mixing coefficient.

Default: .false.
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Flag to enable spatially-varying mixing.

Default: .false.
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Flag to add random fluctuation to orientation

Default: .false.

T reduce major only for cfl violations, F reduce entire tensor for cfl violations

Default: .true.

multiplication factor for cfl check

Default: 0.175

constant eigenvalue ratio

Default: 5.0

max negative factor of major to set minor, set to 0 to force minor to be positive

Default: 0.0

T Set isotropic diffusivity with minor: F set isotropic diffusivity with avg of major and minor

Default: .true.

T to do isotropic using diagnosis

Default: .false.

choice for major axis direction

Valid Values: 'shear', 'east', 'zonal', 'flow', 'pvgrid', 'read'
Default: 'shear'

choice for minor diffusivity

Valid Values: 'simple', 'read'
Default: 'simple'

choice for diffusivity ratio (major/minor)

Valid Values: 'shear', 'simple', 'read'
Default: 'shear'

minor eigenvalue multiplicative factor

Default: 1.0

Save aniso time averaged diagnostics

Default: .true.

multiplicative coefficient for shear dispersion term: MAJOR = MINOR + shrdispfac/MINOR*<(U*dy)^2+(V*dx)^2>

Default: 0.5

T to use simple subcell volume = 1/8 T-cell volume, F to use HTN & HTE

Default: .false.

T do VDC here, F to do in vertical_mix

Default: .false.

Isopycnal diffusivity.

Default: 3.0e7
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Background horizontal diffusivity at k = KMT

Default: 0.0

Background horizontal diffusivity within the surface boundary layer.

Default: 3.0e7

Thickness (GM bolus) diffusivity.

Default: 3.0e7

File name for the time-dependent buoyancy frequency (squared).

Default: '$RUNDIR/buoyancy_freq'

buoyancy_freq_filename format (binary or netCDF).

Valid Values: 'bin', 'nc'
Default: 'nc'

Unitless tuning parameter.

Default: 1.2

Flag for diagnostic bolus velocity computation.

Default: .true.

Flag for diagnostic steering level eddy flux computation.

Default: .true.

Effective upper limit for inverse eddy timescale (unitless).

Default: 500.0

1 of 2 parameters for variation of KAPPA with kappa_type_depth option.

Default: 1.0

1 of 2 parameters for variation of KAPPA with kappa_type_depth option.

Default: 0.0

Depth scale for variation of KAPPA with kappa_type_depth.

Default: 150000.0

Frequency of KAPPA computation.

Valid Values: 'never', 'every_time_step', 'once_a_day'
Default: 'once_a_day'

Choice for KAPPA_ISOP (isopycnal).

Valid Values: 'cons', 'steer', 'depth', 'vmhs', 'hdgr', 'drad', 'bfre', 'bfvm', 'bfhd', 'bfdr', 'edgr'
Default: 'bfre'

specify isopcynal deep diffusivity as fraction of the reference value

Default: 0.1

Maximum value for KAPPA (cm^2/s).

Default: 2.0e7

Minimum value for KAPPA (cm^2/s).

Default: 0.35e7

Choice for KAPPA_THIC (thickness).

Valid Values: 'cons', 'steer', 'depth', 'vmhs', 'hdgr', 'drad', 'bfre', 'bfvm', 'bfhd', 'bfdr', 'edgr'
Default: 'bfre'

specify thickness deep diffusivity as fraction of the reference value

Default: 0.1

Flag to use climatoligical N^2 data instead of model-dependent N^2.

Default: .false.

Maximum slope allowed for bolus transport.

Default: 0.3

Maximum slope allowed for redi diffusion.

Default: 0.3

Choice for slope control.

Valid Values: 'tanh', 'notanh', 'clip', 'Gerd'
Default: 'notanh'

Flag for transition layer parameterization.

Default: .true.

Flag to use ag_bkg_srfbl as maxmium background horizontal diffusivity within the surface boundary layer (rather than using KAPPA_ISOP).

Default: .true.

Efficiency factor: must be between 0.06 and 0.08 [inclusive].

Default: 0.07

Constant horizontal length scale in cm (if luse_const_horiz_len_scale=.true.).

Default: 5.0e5 (5 km)

Flag to use constant horizontal length scale given by hor_length_scale rather than varying length scale with space and time.

Default: .false.

Time scale constant in seconds -- must be between 1 and 4 days [86400 and 345600 seconds].

Default: 8.64e4 (1 day)

Default: one of the following, depending on ocean grid and NK_MODE
IRF_NK_precond_tracers_gx3v7_20150313.nc
IRF_NK_precond_tracers_gx1v6_20150313.nc
IRF_offline_transport_tracers_gx3v7_20150313.nc
IRF_offline_transport_tracers_gx1v6_20150313.nc

Default: 1

Name of the input file containing ocean initial conditions.
Contents of this file depend on init_ts_option. If luse_pointer_files = .true., and 
init_ts_option is 'ccsm_continue', 'ccsm_branch', or 'ccsm_hybrid', then
init_ts_file is ignored and POP reads the file specified in the ocean rpointer files.

Default: Set by CESM scripts based on ocean grid

Data format type of init_ts_file file; either binary ('bin') or netCDF ('nc').

Valid Values: 'bin', 'nc'
Default: 'bin'

Option for initializing ocean conditions.
'ccsm_startup' reads initial temperature and salinity from a file;
'ccsm_continue' and 'ccsm_branch' read ocean initial conditions from a restart file;
'ccsm_hybrid' reads ocean initial conditions from a restart file with a different model date; and
'PHC' remaps PHC Levitus data to POP grid.
'PHC' is a research option that is available but not publicly supported.

Default: 'ccsm_RUNTYPE'

Name of the output file for writing temperature and salinity.
This file is only generated when init_ts_option = 'PHC'

Default: '$RUNDIR/$CASENAME.pop.h.ts_ic'

Data format type of init_ts_outfile file; either binary ('bin') or netCDF ('nc').

Valid Values: 'bin', 'nc'
Default: 'nc'

init_ts_perturb perturbation for ts. 

Default: 1.0e-3

Suboption for initializing temperature and salinity. See CESM documentation. 
This option should only be used by experts.

If init_ts_suboption = 'spunup', then init_ts_option is set (internally) to 'ccsm_startup_spunup';
otherwise, this option has no effect. If the spunup suboption is selected, the model T,S are
initialized from the specified input file, but velocities are initialized to zero, as in 
a 'ccsm_startup' run.
This option should only be used by experts. 

Default: 'null'

Root name for ocean-model log file.

Default: Set by CESM scripts.

Flag to redirect stdout to a log file.

Default: '.true.'

Flag to activate the use of pointer files, which point to the location of restart files.

Default: '.true.'

Number of input / output tasks.

Default: 1

Root filename of the file that points to location of restarts.

Default: rpointer.ocn.* (found in $RUNDIR)

Flag to control the writing of some CFL diagnostics for all vertical levels.
If true, CFL diagnostics at all vertical levels are computed and printed.

Default: .false.

Flag to control the writing of some global diagnostics for all vertical levels.
If true, tracer mean diagnostics at all vertical levels are computed and printed.

Default: .false.

Frequency of computing and printing CFL diagnostics.
Default: 1

Units of time for diag_cfl_freq (frequency of CFL diagnostics).

Valid Values: 'never', 'nyear', 'nmonth', 'nday', 'nhour', 'nsecond', 'nstep'
Default: 'nmonth'

Frequency of computing and printing of global diagnostics.

Default: 1

Units of time for diag_global_freq (frequency of global diagnostics).

Valid Values: 'never', 'nyear', 'nmonth', 'nday', 'nhour', 'nsecond', 'nstep'
Default: 'nmonth'

Name of the output file into which diagnostics are written.

Default: '$RUNDIR/$CASENAME.pop.dd'

Frequency of computing and printing transport diagnostics.

Default: 1

Units of time for diag_transp_freq (frequency of transport diagnostics).

Valid Values: 'never', 'nyear', 'nmonth', 'nday', 'nhour', 'nsecond', 'nstep'
Default: 'nmonth'

Name of the file that contains information for choosing fields for output. 
(the "transport_contents" file name)

Default: Set by CESM scripts based on ocean grid

Name of the output file into which transport diagnostics are written.

Default: '$RUNDIR/$CASENAME.pop.dt'

Name of the output file into which the velocity diagnostics are written.

Default: '$RUNDIR/$CASENAME.pop.dv'

Flag to activate the computation of the velocity diagnostics.

Default: .true.

Flag for activating mcog, the multiple-column ocean grid parameterization.

Default: .false., unless ecosys is turned on

Flag for activating debugging statements in multiple-column ocean grid parameterization.

Default: .false.

bin index for each column

Default: mcog_col_to_bin(nbin) = nbin

call abort if abs(dagg_qsw) exceeds this threshold

Default: 1.0e-10

File for writing overflow diagnostics output.

Default: '$RUNDIR/$CASENAME.do'

File with overflow information.

Default: Set by CESM scripts based on ocean grid.

Flag for using interactive overflows.

Default: .true. for displaced pole grids, .false. for tripole grids.

Flag for using parameterized overflows.

Default: .true. for displaced pole grids, .false. for tripole grids.

Overflow restart type.

Valid Values: 'ccsm_startup', 'ccsm_continue', 'ccsm_hybrid', 'ccsm_branch'
Default: 'ccsm_$RUNTYPE'

Overflow restart file name.

Default: '$RUNDIR/$CASENAME.ro'

Flag for using abio_dic_dic14 module.

Default: 'Set by CESM scripts based on $OCN_TRACER_MODULES'

Flag for using cfc module.

Default: 'Set by CESM scripts based on $OCN_TRACER_MODULES'

Flag for using ecosys module.

Default: 'Set by CESM scripts based on $OCN_TRACER_MODULES'

Flag for using iage module.

Default: 'Set by CESM scripts based on $OCN_TRACER_MODULES'

Filename for initializing iage (if init_iage_option='file').

Default: 'same_as_TS'

init_iage_init_file format (binary or netCDF).

Valid Values: 'bin', 'nc'
Default: 'bin'

Option for initialization of iage.

Valid Values: 'ccsm_startup', 'zero', 'ccsm_startup_spunup', 'restart', 'ccsm_continue', 'ccsm_branch', 'ccsm_hybrid', 'file'
Default: 'ccsm_$RUNTYPE'

Flag for using IRF module.

Default: 'Set by CESM scripts based on $OCN_TRACER_MODULES'

Flag for using sf6 module.

Default: 'Set by CESM scripts based on $OCN_TRACER_MODULES'

Default:

Default:

Default:

Default:

Default:

Default:

Default: CCSM_CO2_PPMV value in env_run.xml

Default:

Source of atmos CO2 and D14C.

Valid Values: 'file', 'const', 'drv_diag'
Default: 'const'

Default:

Default:

Source of atmos D14C.

Valid Values: 'file', 'const', 'lat_bands'
Default: 'lat_bands'

Year in data that corresponds to abio_atm_model_year.

Default: 1

Arbitrary model year.

Default: 1

Default: '1'

Default: 'never'

add Newton-Krylov spinup related tavg variables
Default:
.false.

Default: b.e21.B1850.f09_g17.CMIP6-piControl.001.pop.r.abio_dic_dic14.0391-01-01-00000.nc (gx1v7), none (otherwise)

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Flux formulation.

Valid Values: 'ocmip', 'model'
Default: 'model'

Year in data that corresponds to model_year.

Default: 1850 for OCN_TRANSIENT=1850-2000, 2009 for OCN_TRANSIENT=CORE2,CORE2OMIP,
2018 for OCN_TRANSIENT=JRA,JRA_OMIP, 1 otherwise.

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Filename for initializing cfc (if init_cfc_option='file').

Default: 'same_as_TS'

init_cfc_init_file format (binary or netCDF).

Valid Values: 'bin', 'nc'
Default: 'bin'

Option for initialization of cfc.

Valid Values: 'ccsm_startup', 'zero', 'ccsm_startup_spunup', 'restart', 'ccsm_continue', 'ccsm_branch', 'ccsm_hybrid', 'file'
Default: ccsm_$runtype

Arbitrary model year.

Default: 1850 for OCN_TRANSIENT=1850-2000, 372 for OCN_TRANSIENT=CORE2,CORE2OMIP,
366 for OCN_TRANSIENT=JRA,JRA_OMIP, 1 otherwise.

Default:

Default:

Default:

Default:

Default:

Default:

File name for ascii time series of atm cfc11.

Default: '$DIN_LOC_ROOT/ocn/pop/res_indpt/forcing/cfc_atm_20170512.nc'

first year of non-zero values in pcfc_file
If the effective cfc calendar year is less than this,
and cfc tracers are being read from a restart file,
then a fallback of const=0 for I/O reading is registered.
Default: 1936

Year in data that corresponds to model_year.

Default: 1850 for OCN_TRANSIENT=1850-2000, 2009 for OCN_TRANSIENT=CORE2,CORE2OMIP,
2018 for OCN_TRANSIENT=JRA,JRA_OMIP, 1 otherwise.

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Filename for initializing sf6 (if init_sf6_option='file').

Default: 'same_as_TS'

init_sf6_init_file format (binary or netCDF).

Valid Values: 'bin', 'nc'
Default: 'bin'

Option for initialization of sf6.

Valid Values: 'ccsm_startup', 'zero', 'ccsm_startup_spunup', 'restart', 'ccsm_continue', 'ccsm_branch', 'ccsm_hybrid', 'file'
Default: ccsm_$runtype

Arbitrary model year.

Default: 1850 for OCN_TRANSIENT=1850-2000, 372 for OCN_TRANSIENT=CORE2,CORE2OMIP,
366 for OCN_TRANSIENT=JRA,JRA_OMIP, 1 otherwise.

File name for ascii time series of atm sf6.

Default: '$DIN_LOC_ROOT/ocn/pop/res_indpt/forcing/sf6_atm_20160311.nc'

first year of non-zero values in psf6_file
If the effective sf6 calendar year is less than this,
and the sf6 tracer is being read from a restart file,
then a fallback of const=0 for I/O reading is registered.
Default: 1953

Flux formulation.

Valid Values: 'ocmip', 'model'
Default: 'model'

Default:

Default:

Default:

Default:

Default:

Default:

Default:

Flag for adding correction to Boussinesq approximation.

Default: .false.

Flag to turn on averaging of pressure across three time steps.

Default: .true.

Frequency to write even/odd restart files (units = nstep).

Default: 100000

Flag to turn even_odd restarts on.

Default: .false.

Flag to  apply correction to pressure upon restart.
If .true., surface pressure is modified to correct for an error due to (possible) different timestep. 
Use .false. for exact restart.

Default: .false.

Data format type of restart_outfile file; either binary ('bin') or netCDF ('nc').

Valid Values: 'bin', 'nc'
Default: 'nc'

Number of 'restart_freq_opt' units between the writing of restart files.

Default: 100000

Units of time for restart_freq (restart frequency).

Valid Values: 'never', 'nyear', 'nmonth', 'nday', 'nhour', 'nsecond', 'nstep'
Default: 'nyear'

Name of the restart output filename root.
The model code will create the complete restart output filename
based on the model date.

Default: '$RUNDIR/$CASENAME.pop.r'

Wait prior to beginning to output restart files.
Number of units of restart_start_opt before restart files are started in a run.

Default:  0

Units of time for restart_start. Take restart_start units 
prior to beginning the writing of regular restart files.

Default: 'nstep'

Frequency with which to compute ice (units of ice_freq_opt).

Default:  100000

Option for frequency of computing ice.

Valid Values: 'never', 'coupled', 'nyear', 'nmonth', 'nday', 'nhour', 'nsecond', 'nstep'
Default: 'coupled'

Lowest level from which to integrate ice formation.

Default: 1

Flag for whether POP is coupled to an active ice model.

Default: Depends on $OCN_ICE_FORCING ("inactive" => .false.)

CESM2 default for forming ice every timestep when coupled

Default: .true.

chl_filename format (binary or netCDF).

Valid Values: 'bin', 'nc'
Default: 'bin'

Chlorophyll input filename.

Default: auto-filled by CESM scripts

Chlorophyll option.

Valid Values: 'file', 'model'
Default: auto-filled by CESM scripts

Jerlov water type.

Valid Values: 1-5 (correspond to I, IA, IB, II, and III, respectively)
Default: 3

Short-wave absorption type.

Valid Values: 'top-layer', 'jerlov', 'chlorophyll'
Default: 'chlorophyll'

Flag used for testing when introducing answer changes that will not be
controlled by other namelist flags. Outside of specific tags, this flag will
not have any affect on POP.

Default: .false.

File containing vertical profile of timestep acceleration factors. 

Default: Set by CESM scripts based on ocean grid

Flag to select calendar with leap years.

Default: .false.

Single character used to separate yyyy mm dd in date string. Note a blank space (' ') can be used
to indicate no separator, but this is not recommended.

Default: "-"

Number of timesteps in dt_option units. Serves
as a starting point from which POP determines the exact model timestep size.

Default: Set by CESM scripts based on ocean grid

Selector for units used in determining tracer timestep size; used in conjunction
with dt_count to serve as a starting point from which POP determines
the exact model timestep size.

Not all permissible time_mix_opt values are compatible with all dt_option values.
The recommended option is steps_per_day

Valid Values: 'steps_per_year', 'steps_per_day', 'seconds', 'hours'
Default: 'steps_per_day'

Factor to multiply momentum timestep in order to set the momentum timestep to a
value different from the tracer timestep.  

Default: 1.0

Number of intervals per day into which full and half timesteps must exactly "fit"
when using time_mix_opt='avgfit'

Default: 1

Day number at the start of the experiment. iday0 remains fixed over the course of
the integration; it does not change if experiment is continued.

Default: 2

Hours at the start of the experiment. ihour0 remains fixed over the course of
the integration; it does not change if experiment is continued.

Default: 0

Minutes at the start of the experiment. iminute0 remains fixed over the course of
the integration; it does not change if experiment is continued. 

Default: 0

Month number at the start of the experiment. imonth0 remains fixed over the course of
the integration; it does not change if experiment is continued.

Default: 1

Flag for implicit treatment of Coriolis terms.

Default: .true.

Seconds at the start of the experiment. isecond0 remains fixed over the course of
the integration; it does not change if experiment is continued.

Default: 0

Year at the start of the experiment. iyear0 remains fixed over the course of
the integration; it does not change if experiment is continued.

Default: 1

Flag for timestep acceleration.

Default: .false.

Conserve  across each Robert Filtering step. Note that
this option is unstable, so only use it as a sanity check over a few days at most.

Default: .false.

Print time_manager info every timestep and print initial time-flag info.

Default: .false.

Tuning parameter used in Robert filtering.

Williams, Paul D. "A proposed Modification to the Robert-Asselin Time Filter." Monthly
Weather Review, Vol 137, 2009.

Default: 1.0

Tuning parameter used in Robert filtering.

Williams, Paul D. "A proposed Modification to the Robert-Asselin Time Filter." Monthly
Weather Review, Vol 137, 2009.

Default: 0.20

The CESM identifier for the run.

Default: $CASENAME

Number of stop_option units before POP stops OR date (yyyymmdd) at which POP stops.

Default: 1000

Units of time for 'stop_count'.
In conjunction with 'stop_count', determines stopping time.

Valid Values: 'never', 'eoy', 'eom', 'eod', 'nyear', 'nyears', 'nmonth', 'nmonths', 'nday', 'ndays', 'nstep', 'nsteps', 'date'
Default: 'nyear'

Frequency of mixing timestep. Ignored when time_mix_opt = 'robert'

Default: 17

Option for time mixing:
   avgbb  = DEPRECATED OPTION. leapfrog with occasional time-averaging timestep, immediately
            followed by another time-averaging timestep ("back-to-back" avg). DO NOT USE THIS
            OPTION in scientific experiments.
   avgfit = leapfrog with occasional time-averaging timestep to control stability.
            The timestep is modified such that an integer number of full and half timesteps
            fits into each coupling interval.
   robert = leapfrog with modified Robert-Asselin time filtering to control stability.
            The timestep is modifed such that an integer number of full timesteps
            fits into each coupling interval.

Valid Values: 'robert' 'avgfit', 'avgbb'

Flag to turn on topographic stress.

Default: .false.

Number of passes the topography smoother will make.

Default: 0

Time-centering parameter for implicit vertical mixing.
Use of the default value (1.0) is recommended.
Valid Values: in the range [0.5,1.0]

Default: 1.0

Drag coefficient used in quadratic bottom drag formula (dimensionless).

Default: 1.0e-3

Tracer mixing coefficient to be used with diffusion option.

Default: 10000.0

Momentum mixing coefficient to use with diffusion option. 

Default: 10000.0

Selector for convection method.

Valid Values: 'adjustment', 'diffusion'

'adjustment' -- convection treated by adjustment.
'diffusion'  -- convection treated by large mixing coefficients.

Default: 'diffusion'

Flag to activate computation of vertical mixing implicitly in time.

Default: .true.

Number of passes through the convective-adjustment algorithm.

Default: 2

Selector for method of computing vertical diffusion.

Valid Values: 'const', 'rich', 'kpp'

'const' -- use constant vertical mixing
'rich'  -- use Richardson-number vertical mixing
'kpp'   -- use Kpp vertical mixing

Default: 'kpp'

Vertical diffusivity coefficient (tracer mixing) (cm^2/s).

Default: 0.25

Vertical viscosity coefficient (momentum mixing) (cm^2/s).

Default: 0.25

Background diffusivity (Ledwell).

Default: 0.16

Variation in diffusivity.

Default: 0.0

Banda Sea diffusivity (Gordon).

Default: 1.0

Depth at which diffusivity equals vdc1
Default: 1000.0e02

Equatorial diffusivity (Gregg).

Default: 0.01

Inverse length for transition region.

Default: 4.5e-05

Maximum PSI-induced diffusivity (MacKinnon).

Default: 0.13

Langmuir mixing parameterization option.

Valid Values: 'null', 'vr12-ma', 'vr12-en'
Default: 'vr12-ma'

Flag to decrease Arctic background diffusivity; typically only used as an option
with niw_mixing in research mode.

Default: .false.

Flag to check Ekman, Monin-Obhukov depth limit.

Default: .false.

Flag for using CVMix for mixing instead of POP routines

Default: .true.

Flag for computing double-diffusive mixing.

Default: .true.

Flag to allow horizontally-varying background (need bckgrnd_vdc2=0.0).

Default: .true.

Flag for using inertial mixing parameterization.

Default: .false.

Flag for computing Ri-dependent mixing.

Default: .true.

Flag for computing short-wave forcing.

Default: .true.

Number of times to vertically smooth Ri.

Default: 1

Prandtl number.

Default: 10.0

Coefficient for Richardson number term.

Default: 50.0
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Flag for using near inertial wave mixing.

Default: .false.

Fraction of near inertial wave energy absorbed in the boundary layer.

Default: 0.7

Input file for reading near inertial wave energy flux.

Default: Resolution-dependent

niw_energy_file_fmt (binary or netCDF).

Valid Values: 'bin', 'nc'
Default: 'bin'

Type (internal or external) for near inertial wave energy source.

Default: 'blke'

Fraction of near inertial wave energy available for mixing local to the generation region.

Default: 0.5

Maximum diffusivity for near inertial waves (cm^2/s).

Default: 100.0

Mixing efficiency (portion producing mixing rather than thermal heating).

Default: 0.2

Ratio between observed and modeled near inertial wave strength.

Default: 2.0

Vertical decay scale for turbulence (cm).

Default: 500.0e02

Background vertical diffusivity (cm^2/s).

Default: 0.1

Background vertical viscosity (cm^2/s).

Default: 1.0

Coefficient for Richardson-number function.

Default: 50.0
Note: You must specify both the variable name and namelist name if you change this variable in user_nl_pop!

Flag for setting q==1 in construction of 3D tidal energy field from tidal constituents for plotting/testing'
Do not activate this flag in a scientific experiment.

Default: .false.

Flag for setting q==0.33 in construction of 3D tidal energy field from tidal constituents for plotting/testing'
Do not activate this flag in a scientific experiment.

Default: .false.

Flag to activate 18.6-year lunar cycle.

Default: .false.

Flag to impose tidal_mix_max on all TIDAL_DIFF values.

Default: .true.

Flag to activate collection of fields used to create Melet plot.

Default: .false.

Apply minimum tidal mixing value in specified regions

Default: .false.

Flag to activate tidal mixing.

Default: .true.

Flag to activate Schmittner's method southern ocean modification.

Default: .true.

Flag to impose tidal_mix_max on all TIDAL_DIFF values.

Default: .true.

Number of regions where minimum tidal-mixing values will be applied

Default: 2

Tidal dissipation vertical threshhold in tidal-constituent dataset (cm).
Energy above this level is not included in the parameterization.
Active only when 3D tidal-constituent datasets are used.

Default: 0.0e02

Selector for tidal mixing energy file source. 

'jayne' Jayne 2009
'arbic' not yet available
'ER03'  Egbert and Ray 2003
'GN13'  Green and Nycander 2013
'LGM0'  LGM present day Wilmes 2017
'LGMi5g21' LGM 21kyrbp sea-level reconstruction ig5
'LGMi6g21' LGM 21kyrbp sea-level reconstruction ig6

Default: 'jayne'

Input file containing tidal energy.

Default: 'unknown_tidal_energy_file'

File format of the tidal_energy_file file. 

Valid Values: 'bin,nc'
Default: 'nc'

tidal_energy_ts_file calendar type. 

Ignored if the lunar cycle is not active.

Valid Values: '365'

Default: '365'

Final day used in the model from the lunar-cycle timeseries data record.

The lunar-cycle timeseries data record extends through 2200-12-31 (yyyy-mm-dd).

Ignored if the lunar cycle is not active.

Default: '1'

Numerical representation of the final month used in the model from the lunar-cycle
timeseries data record.

The lunar-cycle timeseries data record extends through 2200-12-31 (yyyy-mm-dd).

Ignored if the lunar cycle is not active.

Default: ''

Final year used in the model from the lunar-cycle timeseries data record.

The lunar-cycle timeseries data record extends through 2200-12-31 (yyyy-mm-dd).

Ignored if the lunar cycle is not active.

Default: '2009'

Starting day used in the model from the lunar-cycle timeseries data record.

The lunar-cycle timeseries data record starts at 1500-01-02 (yyyy-mm-dd).

There are no data points at 29-Feb, but the model can accomodate a Gregorian
calendar anyway, by interpolating between 28-Feb and 01-Mar.

Ignored if the lunar cycle is not active.

Default: '1'

Numerical representation of the starting month used in the model from the lunar-cycle
timeseries data record.

1 ==> January, etc.

The lunar-cycle timeseries data record starts at 1500-01-02 (yyyy-mm-dd).

Ignored if the lunar cycle is not active.

Default: '1'

Starting year used in the model from the lunar-cycle timeseries data record.

The lunar-cycle timeseries data record starts at 1500-01-02 (yyyy-mm-dd).

Ignored if the lunar cycle is not active.

Default: '1948'

File format of the tidal_energy_ts_file file. 

Ignored if the lunar cycle is not active.

Valid Values: 'ascii'
Default: 'ascii'

Array of tidal energy timeseries modulation files (18.6 year tidal cycle),
for each of the tidal constituents M2,S2,K1,O1.

Ignored if the lunar cycle is not active.

Default: 'unknown_tidal_energy_ts_files'

Model year assigned to the selected data year.

Ignored if the lunar cycle is not active.

Default: '1'

Minimum value of N**2 used in tidal diffusion computations.

Default: 1.0e-08

Fraction of energy available for mixing local to the generation region.

Default: 0.33

Number of bottom k-levels where minimum tidal-mixing values will be applied

Default: 6

Name of regions where minimum tidal-mixing values will be applied

Default: 2

Array of minimum tidal-mixing values

Default: 1.0

Maximum for vertical diffusivity and viscosity (cm^2/s).

Default: 100.0

Tidal mixing efficiency. (Gamma)

Default: 0.2

Selector for tidal mixing scheme method.

'jayne'
      Jayne, S. R., and L. C. St. Laurent, 2001: Parameterizing tidal
        dissipation over rough topography. Geophys. Res. Lett., 
        v28, 811-814.

      Simmons, H. L., S. R. Jayne, L. C. St. Laurent, and
        A. J. Weaver, 2004: Tidally driven mixing in a numerical
        model of the ocean general circulation. Ocean Modelling,
        vol 6, 245-263.

      Jayne, Steven R., 2009: The Impact of Abyssal Mixing
        Parameterizations in an Ocean General Circulation Model.
       JPO, vol 39, 1756-1775.

'schmittner'
      Use with 3D datasets only.

      Schmittner, A. and G.D. Egbert, 2014: An improved parameterization
      of tidal mixing for ocean models. Geosci. Model Dev., 7, 211-224, 201


'polzin'
      Melet version is implemented.

      Polzin, K. L., 2009:  An abyssal recipe. Ocean Modelling,
        vol 30, 298-309

      Melet, A. et al, 2013: Sensitivity of the ocean state to the
        vertical distribution of the internal-tide-driven mixing. 
        J. Phys Oceanography, vol 43, 602-615

Default: 'jayne'

Array of tidal-mixing upper TLAT values

Default: 1.0

Array of tidal-mixing lower TLAT values

Default: 1.0

Array of tidal-mixing upper TLON values

Default: 1.0

Array of tidal-mixing lower TLON values

Default: 1.0

File format of the tidal_vars_file_polz file (netCDF only).

Ignored if the 'polzin' tidal_mixing_method_choice option is not active.

Default: 'nc'

Input file containing initialization variables (urms and topographic
roughness) for use in the Polzin tidal mixing method.

Default: 'unknown_tidal_vars_file_polz'

Vertical decay function used in the Schmittner subgridscale scheme.

Ignored if the 'schmittner' tidal_mixing_method_choice option is not active.

Valid Values: 'SSJ02','P09'
Default: 'SSJ02'

Vertical decay scale for turbulence (cm).

Default: 500.0e02