Module ocean_nphysics_new_mod

OVERVIEW

Compute the effects of neutral physics processes (neutral diffusion and neutral skew-diffusion).

OTHER MODULES USED

              constants_mod
                    fms_mod
                 fms_io_mod
                    mpp_mod
            mpp_domains_mod
          ocean_domains_mod
ocean_nphysics_util_new_mod
    ocean_nphysics_flux_mod
  ocean_nphysics_tensor_mod
    ocean_nphysics_skew_mod
    ocean_nphysics_diff_mod
        ocean_operators_mod
       ocean_parameters_mod
            ocean_types_mod
             ocean_util_mod

PUBLIC INTERFACE

PUBLIC ROUTINES

1. ocean_nphysics_new_init

   DESCRIPTION

   Initialises diagnostics, namelists and constants.

   
   
   

2. register fields

   DESCRIPTION

   Register diagnostic fields.

   
   
   

3. neutral_physics_new

   DESCRIPTION

   This public interface computes the effects of neutral physics processes (neutral diffusion and neutral skew-diffusion). --Returns rossby_radius for use in lapgen_friction module. --Returns gm_diffusivity for use in visc_form_drag module --Updates the value of T_prog(n)%th_tendency with the explicit thickness weighted tendency due to neutral physics and also T_prog(n)%K33_implicit with the implicit component.

   
   
   

4. tracer_gradients

   DESCRIPTION

   Compute the tracer derivatives. G(2004) 16.58 dTdx(i) = (T(i+1) - T(i))/dxte dTdT(j) = (T(j+1) - T(j))/dytn dTdz(k) = (T(k) - T(k+1))/dzwt Horizontal derivatives are taken along surfaces of constant vertical coordinate (constant k-level) This approach ensures that when neutral physics defaults to "horizontal" physics next to boundaries, it will do so as horizontal, defined along surfaces of constant s-surfaces, and so will not generate spurious extrema. Additionally, when using generalized vertical coordinates, the neutral diffusion slope should be computed relative to the s-surfaces. The skew diffusion slope should ideally be computed with respect to z-surfaces, as z-surfaces define available potential energy. However, when s and z surfaces are reasonably close, as they are in the interior for zstar and pstar vertical coordinates, then we choose to to dissipate thickness as defined relative to the zstar or pstar surfaces. This should not be such a big deal, and it is certainly easier computationally than worrying about computing two separate sets of slopes. More on this detail is discussed in "Elements of MOM". NOTE: This approach is not appropriate for sigma-models. Indeed, many assumptions in the neutral physics modules need to be rethought for terrain following vertical coordinates.

   
   
   

5. density_calculations

   DESCRIPTION

   This subroutine computes a number of values based on the density gradient. These are the neutral slope vector, the neutral buoyancy frequency, gravity wave speed, Rossby radius and boundary layer depth.

   
   
   

6. gradrho

   DESCRIPTION

   Calculate the raw density gradients. No smoothing or limiting applied here.

   
   
   

7. adjust_drhodz

   DESCRIPTION

   Comments about smoothing drhodz: 1/ Tests in coupled 1-degree model showed extreme sensitivity of MOC to smoothing. GFDL users generally do NOT smooth, hence the default drhodz_smooth_vert=drhodz_smooth_horz=.false. 2/ Smoothing the vertical derivative of drhodz helps produce a regularized (i.e., well behaved) neutral slope vector. 3/ An attempt was made to smooth dTdz and dSdz rather than drhodz. The resulting slope was smooth, but not as smooth as when acting on drhodz itself.

   
   
   

8. neutral_slopes

   DESCRIPTION

   Compute the neutral slope vector along with its magnitude. The neutral slope vector is defined as -grad_h(rho)/(drho/dz).

   
   
   

9. neutral_blayer

   DESCRIPTION

   Locate the vertical index of the neutral boundary layer. This layer is defined as the point where the magnitude of the neutral slope vector first drops below smax, when searching down from the surface.

   
   
   

10. ocean_nphysics_new_restart

    DESCRIPTION

    Write out the restart data for this module

    
    
    

11. ocean_nphysics_new_end

    DESCRIPTION

    Writes out the restart data.

    
    
    

NAMELIST

REFERENCES