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.
Additional interfaces are provided for updating the halo rows of horiz_grid_type derived-type variables and for setting fluxes at the sub-polar to zero.
horiz_grid_mod utilities_mod mpp_domains_mod
use bgrid_halo_mod [, only: update_halo, horiz_grid_boundary, vel_flux_boundary, TEMP, UWND, VWND, 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. horiz_grid_boundary Updates the halo region for variables of derived-type horiz_grid_type. Should be called after horiz_grid_init. vel_flux_boundary Zeros the sub-polar row of fields on the velocity grid. This routine is needed by several dynamics routines for conservation, but should not normally be needed by the user. TEMP, UWND, VWND Integer parameters to be used as the "field" argument in 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: U-flux points use TEMP and V-flux points use either UWND or VWND depending whether a sign flip is desired. SOUTH, NORTH, WEST, EAST, NOPOLE, POLEONLY Integer parameters to be used as the optional "flags" argument to interface update_halo. NOPOLE and POLEONLY apply only to fields UWND and VWND.
call update_halo ( Hgrid, field, data [,flags] ) INPUT field Specifies which field/grid the data is on. You must use the publicly accessible parameters: TEMP, UWND, or VWND. See 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(:,:) or dimension(:,:,:) or dimension(:,:,:,:)] OPTIONAL INPUT flags Integer flag that describes which halo regions should be updated. By default all halo regions are updated. The value of flags should be some combination of the public parameter values SOUTH, NORTH, WEST, EAST, and NOPOLE. For example, to only update the north and east halo regions set flags=NORTH+EAST. The flag for NOPOLE suppresses the halo update of velocity at the poles. An additional flag POLEONLY may be used independently to update only the north and south polar halo rows without updating the interior halo rows. This kind of update will require no processor to processor communication. [integer,scalar] ------------------------------------------------------------------------ call horiz_grid_boundary ( Hgrid ) 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)] ------------------------------------------------------------------------ call vel_flux_boundary ( Hgrid, data ) INPUT 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)] INPUT/OUTPUT data Real data array on velocity grid, may have 2 or 3 dimensions. The dimensions correspond to the x, y and z axes. The data in the sub-polar row will be set to zero. [real,dimension(:,:) or dimension(:,:,:)]
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 value for flags The value of optional argument flags was invalid. This can only happen when the user specifies a value. The value of flags should be set using the public module parameters, and must be in the following range: 0 < flags <= SOUTH+NORTH+WEST+EAST+NOPOLE+POLEONLY. invalid field The input argument "field" has an incorrect value. Make sure you are using one of public parameters: TEMP, UWND, or VWND.
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. If there is no decomposition along the x-axis then the east-west boundaries are updated for global cyclic continuity. All other halo points are updated using MPP_UPDATE_DOMAINS.
None.