[MITgcm-support] Numerical diffusion

[chris hill]

Lars,

  The centered second order scheme is not diffusive, but it is dispersive!

  There is a section in the online reference manual

http://mitgcm.org/r2_web_testing/latest/online_documents/node85.html

on how ( mostly horizontal ) viscosity is calculated. For vertical 
mixing there is Large et al KPP code incorporated into the dynamics.

  Martin Losch at AWI was recently thinking about whether to connect to 
the GOTM suite of schemes. He may have some thoughts on this. Martin 
also has a nice channel setup that he may be willing to share? He is on 
this list.

Chris


Lars Inge Enstad wrote:
> Hello
> 
> I am currently trying to implement an alternative vertical turbulence
> model in MITgcm (GOTM (General Ocean Turbulence Model Burchard et
> al.), has this been tried before?). My question is about the numerical
> diffusion in the momentum advection scheme in MITgcm. How does this
> depend on the spatial and temporal discretisation? What is the momentum
> advection scheme with the lowest possible numerical diffusion in
> MITgcm?  
> 
> One of the test cases I want to verify the code with is channel
> flow. In previous models I have used for channel flow, I have used a
> constant pressure gradient to force the flow. Is there some easy way
> to set up MITgcm this way?
> 
> Best Regards
> Lars Inge Enstad
>