The values related with viscosity/diffusivity

[changjw214]

Hi friends~

I'm trying to make model using different two model(Delft 3d, ROMS)at same estuary, and compare the result.
for this,I want to change 4 things in ROMS(Horizontal eddy viscosity/diffusivity, Vertical eddy viscosity/diffusivity) to let same condition with Delft 3D.
I look into ocean.in, and know VISC= horizontal viscosity, Akv = vertical viscosity
Is it right?? and How about diffusivity??

[kate]

You were in the right neighborhood of the ocean.in file:

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! Harmonic/biharmonic horizontal diffusion of tracer for nonlinear model
! and adjoint-based algorithms: [1:NAT+NPT,Ngrids].

        TNU2 == 0.0d0  0.0d0                    ! m2/s
        TNU4 == 2*0.0d0                         ! m4/s

     ad_TNU2 == 0.0d0  0.0d0                    ! m2/s
     ad_TNU4 == 0.0d0  0.0d0                    ! m4/s

! Harmonic/biharmonic, horizontal viscosity coefficient for nonlinear model
! and adjoint-based algorithms: [Ngrids].

       VISC2 == 5.0d0                           ! m2/s
       VISC4 == 0.0d0                           ! m4/s

    ad_VISC2 == 0.0d0                           ! m2/s
    ad_VISC4 == 0.0d0                           ! m4/s

For the vertical, these are the background values:

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! Vertical mixing coefficients for tracers in nonlinear model and
! basic state scale factor in adjoint-based algorithms: [1:NAT+NPT,Ngrids]

     AKT_BAK == 1.0d-6 1.0d-6                   ! m2/s

  ad_AKT_fac == 1.0d0  1.0d0                    ! nondimensional

! Vertical mixing coefficient for momentum for nonlinear model and
! basic state scale factor in adjoint-based algorithms: [Ngrids].

     AKV_BAK == 1.0d-5                          ! m2/s

  ad_AKV_fac == 1.0d0                           ! nondimensional

Most models use some sort of parameterization, with names like Mellor-Yamada, Large et al., etc. Those are more complex, using both the cppdefs and ocean.in parameters (for GLS at least) to adjust.