Contact: B. Wyman
Reviewers:
Change history: WebCVS Log for bgrid_core_driver.f90
Provides high-level interfaces to the B-grid dynamical core
that allow easy initialization, integration, and diagnostics.
There is a namelist interface for initializing the optional
arguments to subroutine bgrid_core_init.
bgrid_core_mod bgrid_horiz_mod bgrid_vert_mod bgrid_prog_var_mod bgrid_halo_mod bgrid_diagnostics_mod bgrid_integrals_mod bgrid_conserve_energy_mod time_manager_mod fms_mod
use bgrid_core_driver_mod [ ,only: bgrid_dynam_type,
bgrid_core_driver_init,
bgrid_core_driver,
bgrid_core_driver_end,
bgrid_core_time_diff,
get_bottom_data,
put_bottom_data ]
bgrid_dynam_type
A defined-type variable that contains constants needed
by the B-grid dynamical core (see bgrid_core_mod)
bgrid_core_driver_init
Initializes the B-grid dynamical core.
This interface returns values for the "bgrid_dynam_type" and
prog_var_type" derived-type variables. Also internally
initialized are other B-grid derived-type variables for
the horizontal and vertical grid constants.
bgrid_core_driver
A wrapper for integrating the dynamical core one (atmospheric) time step.
Note that only the tendencies of prognostic variables are updated.
bgrid_core_time_diff
Performs the time differencing of the prognostics variables
and outputs diagnostics for the B-grid dynamical core.
bgrid_core_driver_end
A wrapper for terminating the dynamical core.
get_bottom_data, put_bottom_data
Routines for getting and putting data at the model level
closest to the ground.
NOTES
* A namelist interface called bgrid_core_driver_nml is read
from file input.nml.
type (bgrid_dynam_type)
See bgrid_core_mod for details.
call bgrid_core_driver_init ( Time_init, Time, Time_step,
Var, Var_dt, Dynam, phys_axes )
DESCRIPTION
Returns initialized/allocated values for the "bgrid_dynam_type"
and "prog_var_type" derived-type variables. Also internally
initialized are other B-grid derived-type variables for the
horizontal and vertical grid constants.
INPUT
Time_init The initial (or base) time. [time_type]
Time The current time. [time_type]
Time_step The atmospheric model/physics time step. [time_type]
INPUT/OUTPUT
Var A derived-type variable that contains the prognostic
variables for the B-grid dynamical core.
The returned values will have been initialized
by prog_var_mod (most likely read from a restart file).
[type(prog_var_type)]
Var_dt A derived-type variable that contains the prognostic
variable time tendencies. The returned value is zero.
[type(prog_var_type)]
Dynam A derived-type variable that contains almost everything
needed by the dynamical core.
[type(bgrid_dynam_type)]
OUTPUT
phys_axes Axis identifiers as returned by the diagnostics manager
and needed for subsequent calls to the diagnostics manager.
[integer, dimension(4)]
call bgrid_core_driver ( Time_diag, Var, Var_dt, Dynam, omega )
DESCRIPTION
Updates the prognostic variable tendencies with the dynamical
core tendencies for the current atmospheric time step.
Also calls diagnostics routines for outputting the dynamical
core tendencies.
INPUT
Time_diag The diagnostics time, usually the current time + time step.
[type(time_type)]
Var A derived-type variable that contains the B-grid's
prognostic variables.
[type(prog_var_type)]
INPUT/OUTPUT
Var_dt A derived-type variable that contains the TENDENCIES
for the B-grid's prognostic variables.
[type(prog_var_type)]
Dynam The derived-type variable returned by a previous call
to bgrid_core_driver_init (see above).
[type(bgrid_dynam_type)]
OUTPUT
omega The omega diagnostic (from the thermodynamic equation) in
pascals per second. The array should have horizontal dimensions that
are consistent with the data domain of the B-grid dynamical core.
[real, dimension(ilb:,jlb:,:)]
call bgrid_core_time_diff ( omega, Time_diag, Dynam, Var, Var_dt )
DESCRIPTION
Performs the time differencing of the prognostics variables
and outputs diagnostics for the B-grid dynamical core.
INPUT
omega The pressure vertical velocity in Pascals/second.
This is only needed for diagnostic purposes.
[real, dimension(:,:,:)]
Time_diag The diagnostics time, usually the current time + time step.
[type(time_type)]
Dynam The derived-type variable returned by a previous call
to bgrid_core_driver_init (see above).
[type(bgrid_dynam_type)]
INPUT/OUTPUT
Var The prognostic variables. The input quantities are at the
current and on output they are at the next time step.
[type(prog_var_type)]
Var_dt The time tendencies for the prognostic variables.
The output tendencies will have been set to zero.
[type(prog_var_type)]
call bgrid_core_driver_end (Dynam)
DESCRIPTION
Termination routine for the B-grid dynamical core.
INPUT
Dynam The derived-type variable returned by a previous call
to bgrid_core_driver_init (see above).
[type(bgrid_dynam_type)]
call get_bottom_data ( a, b, a_bot, b_bot, [, k_bot] )
DESCRIPTION
Given a pair of 3-dimensional model fields this interface returns
the 2-dimensional fields at the model level closest to the ground.
If optional argument "kbot" is NOT present the returned field
will be the 2-d field at k = size(a,3).
INPUT
a, b Three-dimension fields on the model grid.
The last dimension varies from the top of the atmosphere
towards the surface.
[real, dimension(:,:,:)]
OUTPUT
a_bot, b_bot Data located at the model level closest to the ground.
Must have the same size as the first two dimensions of a and b.
[real, dimension(:,:)]
OPTIONAL INPUT
k_bot The vertical index for the model level closest to
the ground. Must have the same size as a_bot and b_bot.
[integer, dimension(:,:)]
call put_bottom_data ( a_bot, b_bot, a, b [, k_bot] )
DESCRIPTION
Puts 2-dimensional data given at the lowest model level
into their 3-dimensional model fields.
INPUT
a_bot, b_bot Data located at the model level closest to the ground.
This data will be inserted into arrays a and b.
[real, dimension(:,:)]
INPUT/OUTPUT
a, b Three-dimension fields on the model grid.
[real, dimension(:,:,:)]
OPTIONAL INPUT
k_bot The vertical index for the model level closest to
the ground. Must have the same size as a_bot and b_bot.
[integer, dimension(:,:)]
&bgrid_core_driver_nml
damp_scheme Determines how horizontal damping coefficients
vary with latitude.
= 1, constant
= 2, varies as inverse of diagonal grid distance
= 3, varies as inverse of x-axis grid distance
Note: damp_scheme = 1 is recommended,
damp_scheme = 2,3 is experimental.
[integer, default: damp_scheme = 1]
damp_order_wind The horizontal damping order for momentum,
damp_order_temp temperature, and default order for all
damp_order_tracer prognostic tracers. The damping order must be
an even number; damp_order = 0 turns off damping.
[integer, default: damp_order = 4]
damp_coeff_wind The horizontal damping coefficients for
damp_coeff_temp momentum, temperature, and default value for
damp_coeff_tracer all prognostic tracers. The coefficients are
expressed as non-dimensional values for the
second-order diffusion operator (range = 0,1).
[real, default: damp_coeff = 0.50]
slope_corr_wind The topography slope correction applied to horizontal
slope_corr_temp damping of momentum and temperature (including all
prognostic tracers). The coefficients (with range = 0,1)
are expressed as arrays of size 4. The first 3 values are
coefficients for the lowest 3 model layers, the last value
represents the remaining uppermost layers. A NON-ZERO
value turns the correction ON. Typical values might be
(/ .25, .50, .75, .95 /).
[real, dimension(4), default: slope_corr = 0.,0.,0.,0.]
advec_order_wind The advection order for momentum, temperature,
advec_order_temp and default order for all prognostic tracers.
advec_order_tracer The advection order must be an even number.
[integer, default: advec_order = 2]
advec_coeff_wind Coefficients for modified Euler-backward advection
advec_coeff_temp scheme for momentum, temperature, and all
advec_coeff_tracer prognostic tracers.
NOTE: advec_coeff=0 is the Euler-forward scheme which
is unstable, advec_coeff=1 is the Euler-backward scheme
which is highly dissipative.
[real, default: advec_coeff = 0.7]
num_fill_pass The number of successive passes applied in the tracer
borrowing/filling scheme. This conservative scheme is
used to fill negative tracer values. It is applied in
both the vertical and horizontal directions.
Each successive pass should remove more negative values,
however an optimum number of passes is probably between 1-3.
This is applied after advection to all prognostic tracers.
[integer, default: num_fill_pass = 1]
grid_sep_coeff Coefficient to suppress grid-separation problem
associated with the B-grid. Currently, this option has been
disabled within the model, so that this coefficient does nothing.
[real, default: grid_sep_coeff = 0.00]
filter_option Determines how polar filtering is performed.
filter_option = 0, NO filtering
= 1, not implemented
= 2, filter horiz OMG/DIV,
advec mass tendencies,
and momentum
[integer, default: filter_option = 2]
filter_weight Weight applied to the polar filter that will
increase (or decrease) the strength of the standard
polar filter response function.
SS(new) = SS(std)**filter_weight,
where SS(std) is the Arakawa and Lamb response function.
[integer, default: filter_weight = 1 ]
ref_lat_filter The reference latitude at which polar filtering
(in each hemisphere) will begin to be applied.
Setting this argument >= 90. will turn off
polar filtering.
[real, default: ref_lat_filter = 60.]
num_sponge_levels Number of uppermost model level where a band-pass
filter is applied to damp undesirable waves.
Currently num_sponge_levels > 1 is not allowed.
If num_sponge_levels = 0, no damping is done.
[integer, default: num_sponge_levels = 0 ]
sponge_coeff_wind Damping coefficients for the sponge layer(s) in
sponge_coeff_temp the uppermost model levels. Coefficients have been
sponge_coeff_tracer normalized and must be in the range [0,1].
If num_sponge_levels = 0, the value of the coefficients
is ignored. There is no option to specify coefficients
that vary with level, although currently
num_sponge_levels > 1 is not allowed.
[real, default: sponge_coeff = 0.]
halo The number of halo rows along all (NEWS) boundaries.
There is currently no namelist option that allows unequal
halo boundary. NOTE: Additional halo rows are not
necessary when using higher order horizontal damping or
advection, and may in fact result in poorer cpu performance.
[integer, default, halo = 1]
num_adjust_dt The number of adjustment time steps for each advection
time step, where num_adjust_dt >= 1.
[integer, default: num_adjust_dt = 3]
num_advec_dt The number of advection/dynamics time steps for each
atmospheric/physics time step, where num_advec_dt >= 1.
[integer, default: num_advec_dt = 1]
decomp The domain decomposition, where decomp(1) = x-axis
decomposition, decomp(2) = y-axis decomposition.
* If decomp(1)*decomp(2) does not equal the number
of processors the model will fail.
* If decomp(1)=decomp(2)=0 then default rules apply.
* By default, one-dimensional decomposition (in Y) is used.
When there is fewer than 2 points per processor, then 2-D
decomposition is used.
[integer, dimension(2), default: decomp = 0,0]
do_conserve_energy If TRUE the temperature tendency will be updated to
guarantee that the dynamical core conserves total energy.
The correction is applied to a uniform global value.
[logical, default: do_conserve_energy=.false.]
verbose Flag that control additional printed output.
Currently, this option is not being used.
[integer, default: verbose = 0]
NOTES
None.
None.
None.