[MITgcm-devel] heff_max...more sea ice issues

[Matthew Mazloff]

Thanks for the help...but I am a bit confused.  Two things

1) Re model efficiency and time stepping...I see there are 3  
parameters.  I am guessing  SEAICE_deltaTtherm should be the ocean  
dynamics time-step as the forcing comes from this.  The other time  
stepping parameters are  SEAICE_deltaTdyn  and SEAICE_deltaTevp which  
I assume are the timesteps for each dynamic solver (LSR and EVP)  
respectively.  And as I understand it LSR can use the "large"  
timestep, but the EVP should use the "small" timestep...is this  
correct?  And I am not using both at the same time obviously, but you  
are saying I should try both independently because it is not obvious  
which is faster.

2)More important than efficiency (right now anyway) is stability.   
Jinlun, your first email seemed to suggest I try LSR with a half day  
time step and LSR_ERROR=1e-4, or try EVP with "small" timestep.  Are  
either of these methods likely to be more stable?

Thanks again for all the help and sorry if I got the info completely  
wrong,
Matt



On Dec 21, 2006, at 2:48 PM, Jinlun Zhang wrote:

> If you want to save a lot of time on ice dynamics, use half day or  
> one day time step (not very desirable of course, but I don't think  
> the code would blow up). Ocean dynamics time step would be good  
> enough for the 'smaller' time step.
> J
>
> Dimitris Menemenlis wrote:
>
>> Jinlun, my question was what is your definition of "large" and  
>> "smaller".
>> Specifically, what time step should Matt be using.  Cheers, Dimitris
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