Contact: B. Wyman
Reviewers:
Change history: WebCVS Log for bgrid_halo.f90
Provides an interface for updating the B-grid dynamical core
halo rows and columns, including the polar halo rows.
See the notes section for a description of the polar
boundary condition.
Optional arguments allow for customized halo updates.
horiz_grid_mod
utilities_mod
mpp_domains_mod
use bgrid_halo_mod [, only: update_halo,
vel_flux_boundary,
TEMP, UWND, VWND, WIND,
SOUTH, NORTH, WEST, EAST,
NOPOLE, POLEONLY ]
update_halo
Updates all requested rows in the halo region for a requested
field of type: TEMP, UWND, or VWND. By default all boundaries
will be updated. To update only specific boundaries use the
public parameters: SOUTH, NORTH, WEST, EAST, NOPOLE, and POLEONLY.
vel_flux_boundary
Zeros-out the sub-polar row of meridional velocity flux fields.
This routine is needed by several dynamics routines for conservation,
but should not normally be needed by the user.
TEMP, UWND, VWND, WIND
Integer parameters to be used for the "field" argument to
interface update_halo. The VWND value will result in a sign flip
beyond the polar rows. Data at auxilary mass flux points can
also use these values: UFLX points use TEMP and VFLX points use
either UWND or VWND depending whether a sign flip is desired.
The WIND value is used with the 4D version to process the
u,v components together.
SOUTH, NORTH, WEST, EAST
Integer parameters to be used with the optional "halos" argument to
interface update_halo. By default all halos are updated.
NOPOLE, POLEONLY
Integer parameters to be used with the optional "flags" argument to
interface update_halo. NOPOLE applies only to fields UWND, VWND,
and WIND. POLEONLY applies south and north halo updates only
at the polar boundaries.
call update_halo ( Hgrid, field, data [, halos, flags] )
INPUT
field Specifies which field/grid the data is on.
You must use the publicly accessible parameters:
TEMP, UWND, VWND, or WIND.
See the notes below and the description of
these parameters above.
[integer,scalar]
INPUT/OUTPUT
Hgrid The derived-type variable returned by a previous call to horiz_grid_init.
See the module horiz_grid_mod for details.
[type(horiz_grid_type)]
data Data array on any valid grid, may have 2, 3, or 4 dimensions.
The dimensions correspond to the x, y and z axes, and tracer number.
[real, dimension(Hgrid%ilb:,Hgrid%jlb:)]
[real, dimension(Hgrid%ilb:,Hgrid%jlb:,:)]
[real, dimension(Hgrid%ilb:,Hgrid%jlb:,:,:)]
OPTIONAL INPUT
halos Integer flag that describes which halo regions should be updated.
The value of "halos" should be some combination of the public
parameters: SOUTH, NORTH, WEST, EAST. By default all halo regions
are updated. For example, to only update the north and east halo
regions set halos=NORTH+EAST.
[integer]
flags Can be set to either: NOPOLE or POLEONLY.
The NOPOLE flag suppresses the halo update of velocity
components at the pole row only.
The POLEONLY flag is used to update only the north and
south polar halos rows without updating the interior
halo rows. This kind of update will require no
processor to processor communication.
[integer]
NOTE
The field identifier WIND can only be used with the 4D version
of this interface. The 4th dimension must have size=2, corresponding
to the UWND and VWND components, respectively.
------------------------------------------------------------------------
call vel_flux_boundary ( Hgrid, data )
INPUT
Hgrid Data structure returned by a previous call to horiz_grid_init.
See the module horiz_grid_mod for details.
[type(horiz_grid_type)]
INPUT/OUTPUT
data Real data array located between velocity points along
the y-axis (on the UFLX grid). The data in the sub-polar
row will be set to zero.
[real,dimension(:,Hgrid%jlb:) or dimension(:,Hgrid%jlb:,:)]
Fatal errors in update_halo
i dimension has wrong size
The 1st (i) dimension of input/output argument data must
have a size equal to Hgrid % isize (the entire i dimension).
j dimension has wrong size
The 2nd (j) dimension of input/output argument data must
have a size equal to Hgrid % jsize (the entire j dimension).
invalid field
The input argument "field" has an incorrect value. Make sure
you are using one of public parameters: TEMP, UWND, VWND, or WIND.
4th dimension must have size 2 for wind components
If WIND fields are specified then the 4th dimension of
data array must have size of 2.
None.
At the north-south polar boundaries the following
boundary conditions are applied:
a) Velocities at the poles are equal to zero
u(i,p) = 0
v(i,p) = 0
b) Halo points along the north and south polar boundaries
are set as follows:
T(i,p+1/2) = T(i,p-1/2)
u(i,p+1) = u(i,p-1)
v(i,p+1) = -v(i,p-1)
where p + # is a halo row and p - # is a row within
the computational domain.
Implement realistic cross-polar flow boundary condition.