PUBLIC INTERFACE ~ PUBLIC DATA ~ PUBLIC ROUTINES ~ NAMELIST ~ DIAGNOSTIC FIELDS ~ ERROR MESSAGES ~ REFERENCES ~ NOTES

Module ocean_mixdownslope_mod

Contact:  S.M. Griffies
Reviewers: 
Change History: WebCVS Log

OVERVIEW

Mixing of tracer between dense shallow parcel and deeper parcels downslope.

Mixing of tracer properties as dense shallow parcel is discharged into deeper water to approach the parcel's depth of neutral buoyancy. This module can be characterized as a mixture of the approach from Campin and Goosse (1999) and slope convection.

OTHER MODULES USED

       constants_mod
    diag_manager_mod
             fms_mod
     mpp_domains_mod
             mpp_mod
   ocean_density_mod
   ocean_domains_mod
ocean_parameters_mod
     ocean_types_mod
      ocean_util_mod
 ocean_workspace_mod

PUBLIC INTERFACE

ocean_mixdownslope_init:
mixdownslope:

PUBLIC DATA

None.

PUBLIC ROUTINES

  1. ocean_mixdownslope_init

    DESCRIPTION
    Initial set up for mixing of tracers into the abyss next to topography.


  2. mixdownslope

    DESCRIPTION
    Compute thickness and density weighted tracer tendency [tracer*rho*m/s] due to exchange of tracer properties in regions where density-driven downslope transport is favorable.

    Allow for exchanges to occur over horizontally distant points, so long as the dense shallow parcel finds that it will sit on the bottom of the horizontally adjacent columns. Doing so requires a search algorithm, which requires some if-test logic as well as extended halos. Note that the halos cannot be extended to larger than the size of the computational domain on a processor. This restriction limits the extent that we can search horizontally.

    The rates for the exchange are functions of the topographic slope and the density differences between parcels.

    This scheme can be characterized as a slope convection based on logic incorporated into the overflow and overexchange schemes.



NAMELIST

&ocean_mixdownslope_nml

use_this_module
For using this module. Default use_this_module=.false.
[logical]
debug_this_module
For debugging
[logical]
do_bitwise_exact_sum
Set true to do bitwise exact global sum. When it is false, the global sum will be non-bitwise_exact, but will significantly increase efficiency. The default value is false.
[logical]
mixdownslope_npts
Number of horizontally distant points used in search downslope. Note: it is not possible to have mixdownslope_npts greater than or equal to the computational domain extents, as this would require updates across multiple processors. Default mixdownslope_npts=1.
[integer]
mixdownslope_frac_central
Fraction of the central cell that participates in downslope mixing in any particular direction. Default mixdownslope_frac_central=0.25
[real]
mixdownslope_weight_far
To place more weight on points further from central point. This may be done to enhance properties getting downslope. Default is mixdownslope_weight_far=.false.
[logical]
mixdownslope_width
Width of the re-weighting function used to emphasize points further along in the search for exchange points. Default mixdownslope_width=1.
[integer]
read_mixdownslope_mask
For reading in a mask that selects regions of the domain where mixdownslope is allowed to function (mask=1) or not to function (mask=0). Default read_mixdownslope_mask=.false., whereby mixdownslope_mask is set to tmask(k=1).
[logical]
mixdownslope_mask_gfdl
For modifying the mixdownslope mask based on reading in the GFDL regional mask. Default mixdownslope_mask_gfdl=.false.
[logical]

DATA SETS

None.

ERROR MESSAGES

None.

REFERENCES

  1. Campin and Goosse (1999): Parameterization of density-driven downsloping flow for a coarse-resolution model in z-coordinate", Tellus 51A, pages 412-430
  2. S.M. Griffies, Elements of mom4p1 (2006) NOAA/Geophysical Fluid Dynamics Laboratory

COMPILER SPECIFICS

None.

PRECOMPILER OPTIONS

None.

LOADER OPTIONS

None.

TEST PROGRAM

None.

KNOWN BUGS

None.

NOTES

None.

FUTURE PLANS

None.

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