module vert_advection_mod

Overview

Computes the tendency due to vertical advection for an arbitrary quantity.

The advective tendency may be computed in advective form (for use in spectral models) or flux form. The spatial differencing may be centered (second or fourth order) or finite volume (van Leer) using a piecewise linear method.

Other modules used

fms_mod

Public interface

use vert_advection_mod [, only:  vert_advection,
                                 SECOND_CENTERED, FOURTH_CENTERED, VAN_LEER_LINEAR,
                                 FLUX_FORM, ADVECTIVE_FORM  ]
vert_advection:

Computes the vertical advective tendency for an arbitrary quantity. There is no initialization routine necessary.


Public routines

  1. Vert_advection

    call vert_advection ( dt, w, dz, r, rdt [, mask, scheme, form] )

DESCRIPTION
   This routine computes the vertical advective tendency for
   an arbitrary quantity. The tendency can be computed using
   one of several different choices for spatial differencing
   and numerical form of the equations. These choices are
   controlled through optional arguments.
   There is no initialization routine necessary.

INPUT
   dt   time step in seconds [real]

   w    advecting velocity at the vertical boundaries of the grid boxes
        does not assume velocities at top and bottom are zero
        units = [units of dz / second]
        [real, dimension(:,:,:)]
        [real, dimension(:,:)]
        [real, dimension(:)]

   dz   depth of model layers in arbitrary units (usually pressure)
        [real, dimension(:,:,:)]
        [real, dimension(:,:)]
        [real, dimension(:)]

   r    advected quantity in arbitrary units
        [real, dimension(:,:,:)]
        [real, dimension(:,:)]
        [real, dimension(:)]

OUTPUT
   rdt  advective tendency for quantity "r" weighted by depth of layer
        units = [units of r * units of dz / second]
        [real, dimension(:,:,:)]
        [real, dimension(:,:)]
        [real, dimension(:)]

OPTIONAL INPUT
   mask    mask for below ground layers,
           where mask > 0 for layers above ground
           [real, dimension(:,:,:)]
           [real, dimension(:,:)]
           [real, dimension(:)]

   scheme  spatial differencing scheme, use one of these values:
              SECOND_CENTERED = second-order centered
              FOURTH_CENTERED = fourth-order centered
              VAN_LEER_LINEAR = piecewise linear, finite volume (van Leer)
           [integer, default=VAN_LEER_LINEAR]

   form    form of equations, use one of these values:
              FLUX_FORM      = solves for -d(w*r)/dt
              ADVECTIVE_FORM = solves for -w*d(r)/dt
           [integer, default=FLUX_FORM]

NOTE
   The input/output arrays may be 1d, 2d, or 3d.
   The last dimension is always the vertical dimension.
   For the vertical dimension the following must be true:
   size(w,3) == size(dz,3)+1 == size(r,3)+1 == size(rdt,3)+1 == size(mask,3)+1
   All horizontal dimensions must have the same size (no check is done).

Error messages

Errors in vert_advection_mod

vertical dimension of input arrays inconsistent The following was not true: size(w,3) = size(r,3)+1. invalid value for optional argument scheme The value of optional argument scheme must be one of the public parameters SECOND_CENTERED, FOURTH_CENTERED, or VAN_LEER_LINEAR. invalid value for optional argument form The value of optional argument form must be one of the public parameters FLUX_FORM or ADVECTIVE_FORM.


References

  1. Lin, S.-J., W.C. Chao, Y.C. Sud, and G.K. Walker, 1994: A class of the van Leer-type transport schemes and its application to the moisture in a general circulation model. Mon. Wea. Rev., 122, 1575-1593.


Notes

None.