Module ocean_advection_velocity_mod
OVERVIEW
Advection velocity components for tracer and momenta transport
The module computes the horizontal and vertical components to the
advection velocity on the face of tracer and velocity cells.
The three components are related by continuity.
The horizontal components to the advection velocity are
thickness weighted. Some diagnostics related to volume transport
classified according to both depth and density classes are also computed.
OTHER MODULES USED
axis_utils_mod
constants_mod
diag_manager_mod
fms_mod
mpp_domains_mod
mpp_mod
ocean_domains_mod
ocean_operators_mod
ocean_types_mod
ocean_workspace_mod
ocean_obc_mod
PUBLIC INTERFACE
PUBLIC DATA
None.
PUBLIC ROUTINES
-
ocean_advection_velocity_init
-
DESCRIPTION
- Initialize the advection velocity module
-
ocean_advection_velocity
-
DESCRIPTION
- Compute thickness weighted advection velocities normal to
side faces of U-cells and T-cells on a b-grid. Also compute
vertical advection velocity normal to bottom faces of U-cells and T-cells.
NAMELIST
&ocean_advection_velocity_nml
-
max_advection_velocity
This is a check value used to determine if the time steps will result in
linearly stable advection. If set to a number < 0, then model will estimate the
value as a function of maximum grid size.
Note that this time step check is not rigorous, and it depends on the details of
the advection scheme. Nonetheless, it provides some useful warning for setting the
time steps in the model.
[real, units: meter/sec]
DATA SETS
None.
ERROR MESSAGES
None.
REFERENCES
- R.C. Pacanowski and S.M. Griffies
The MOM3 Manual (1999)
- S.M. Griffies, M.J. Harrison, R.C. Pacanowski, and A. Rosati
A Technical Guide to MOM4 (2003)
COMPILER SPECIFICS
None.
PRECOMPILER OPTIONS
None.
LOADER OPTIONS
None.
TEST PROGRAM
None.
KNOWN BUGS
None.
NOTES
The expressions for the horizontal components for tracer advection
allow for a proper conversion between pressure work and buoyancy.
The remapping operators are derived from considerations of linear
interpolation and volume conservation. A "remapping error" is
computed to determine the consistency between the tracer and velocity
grid advection velocities. This error is roundoff only for cases
where the horizontal tracer and velocity grids are linearly related,
as is the case for the spherical coordinate version of mom4. The
tripolar version of mom4 does not have tracer and velocity grids
related linearly, and so the "remapping error" is nontrivial. The
significance of this error is unclear. No adverse effects have been
identified.
The vertical velocity components for both the tracer and velocity cells
are diagnosed via continuity (either volume or mass conservation depending
on the use of the Boussinesq or non-Boussinesq versions of mom4).
FUTURE PLANS
None.