[MITgcm-support] cheapAML+global_ocean.90x40x15: it's all NaNs

[Gus Correa]

Hi Prof. Deremble

Thank you very much for your help,
and for your kind offer to run the experiment yourself.

FYI, I am using MITgcm_c65x.

**

1) Files on the ftp site:

I put the binary forcing files for the cheapAML+global_ocean.90x40x15
experiment, along with the "data" (namelist) files that I used
in our ftp server:

ftp.ldeo.columbia.edu

which you can access via anonymous sftp or
through a browser, with the URL:

ftp://ftp.ldeo.columbia.edu/

Via sftp, the directory with the files is:

/home/ftp-pub/gus/2deremble

If you use the browser it spells this way:

ftp://ftp.ldeo.columbia.edu/pub/gus/2deremble/

If you have any problem to copy the files, please let me know.

**

2) More attempts to run the experiment still produce NaNs

Also, I ran the experiment with cheapamlYperiodic = .FALSE.
With FluxFormula=COARE3 it gives me NaNs on step 2 if I use 
cheapaml_ntim = 10.
If I increase cheapaml_ntim  to 100, 1000, or 10000,
it starts the NaNs on step 258 (on STDERR.0000 at least).
With FluxFormula=LANL it starts the NaNs on step 2,
regardless of the value of cheapaml_ntim.

**

3) Question

This experiment is on a 4x4 degrees grid.
Could it be that the cheapAML is inherently unstable
at this coarse resolution? (I hope not!)

**

Many thanks,
Gus Correa


On 11/10/2016 03:41 PM, Bruno Deremble wrote:
 >
 > HI Gus,
 >
 > I mean, you need
 > cheapamlYperiodic = .FALSE.
 >
 > because your domain is not periodic in y.
 >
 > Can you put your configuration and init files somewhere? I can try to
 > look at it.
 >
 > bruno
 >

On 11/09/2016 02:45 PM, Gus Correa wrote:
> Hi Prof. Deramble
>
> Thank you very much for your help.
> I made the changes you suggested, but I continue to have NaNs.
> Please, see my answers and new questions inline.
>
> On 11/07/2016 06:16 PM, Bruno Deremble wrote:
>>
>> Hi Gus,
>>
>> your config looks good to me.
>> a few minor points:
>>
>> I think you don't want
>> cheapamlYperiodic = .TRUE.
>> because you are on a lat/lon grid
>
> I was confused by the comments on the code,
> that are probably applicable only to the cheapAML
> box model in the MITgcm verification experiment.
> Anyway, I switched to cheapamlYperiodic = .TRUE.
>
>>
>>
>> cheapaml_ntim = 10000
>> is probably too much. I would set
>> cheapaml_ntim ~ Umax(atm)/Umax(ocean) so O(10)
>>
>
> Yes, I started with 5, then 10, based on
> the same scaling argument you wrote above.
> However, because I only got NaNs, I thought I might
> have a CFL problem in the cheapAML, so I increased it
> progressively to 100, 1000, 10000, but that didn't help either.
> I switched back to cheapaml_ntim = 10.
>
>>
>> I would use COARE3 (and not LANL)
>> FluxFormula='COARE3'
>>
>
> I applied this change also.
> However, I wonder if, in order to use COARE3,
> I need additional input files to the cheapAML (i.e.,
> not just Usurf,Vsurf,Qsurf,Tsurf, ShortWavesurf).
> Do I? Maybe I need also a wave model file?
> Not sure.
>
>> If none of these work, can you give me a link to your binary files? I
>> can try to run your config later this week.
>>
>> bruno
>>
>>
>
> Thank you,
> Gus Correa
>
>
>
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