[MITgcm-devel] SEAICEuseEVP and SEAICE_deltaTevp

[Martin Losch]

And deltaTevp is exactly the problem that made me "retire" the flag SEAICEuseEVP (actually removed it from the namelist without warning which I remember caused some irritation). It's not very clear, which value to use for deltaTevp. deltaT/120 is a reasonable choice (and often recommended), but by no means universal. I prefer to leave it as it is and thus force users to learn a little about EVP before blindly using it.

SEAICEuseEVP should not even be accepted in data.seaice. It's in any namelist anymore. (It was for a short time in the beginning.)

I also remember that there is an online model documentation. In the seaice-description there is a subsection about EVP where I tried to explain how to turn on EVP:
<http://mitgcm.org/public/r2_manual/latest/online_documents/node253.html>
I suggest that before you change anything in the defaults, a user should read the documentation. 

Possibly we can improve the text (and I am open to suggestions for that). One suggestion I have is that some of the numerous new CPP-flags in seaice_growth are documented (basically added to table 6.16).

Martin



On Jul 26, 2011, at 12:03 AM, Pierre Rampal wrote:

> Hum, I have no arguments against that. I was, me, one of the first to be confused by this point, as well as Gunnar who thought that he was using EVP in his simulations for a while, whereas he was not...
> But, what's about the value your propose Dimitris? has it just to be very small compared to the time step?
> Pierre.
> 
> On Jul 25, 2011, at 2:07 PM, Dimitris Menemenlis wrote:
> 
>> One question I often get is "how do you turn on EVP?".
>> 
>> It is a little counterintuitive that SEAICEuseEVP=.TRUE.
>> in data.seaice is ignored.
>> 
>> Would it be OK if I added a couple of lines in seaice_readparms.F
>> that specify a default SEAICE_deltaTevp ~ deltatT/120
>> when SEAICEuseEVP=.TRUE. ?
>> 
>> Let me know
>> 
>> Dimitris Menemenlis
>> 
>> 
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