[MITgcm-devel] thsice + seaice

Mon May 5 19:03:46 EDT 2008

Martin, now that I have solved my diagnostics problem, I finally also  
have a thsice + seaice setup running on the Arctic grid.  To get  
around the "BBerr - Bug: IceT(1) > Tmlt 239  32  1  1 -5.376776E-02  
-5.400000E-02" errors, I initialized with sea ice thickness only,  
i.e., no area and no snow.  Maybe snow plus thickness would have  
worked also.  I did not try that combination.  But area plus thickness  
initialization did not work at all for me.  D.

Dimitris Menemenlis <menemenlis at sbcglobal.net>
5056 Oakwood Ave, La Canada, CA 91011-2450
tel/fax: 818-790-6735;  cell: 818-625-6498

On May 2, 2008, at 6:23 AM, Martin Losch wrote:

> FYI,
> I have put a quick and rough comparison of the seaice and thsice  
> THERMODYNAMICS here:
> <http://mitgcm.org/~mlosch/cmpice.tar>
> This is a spinup-run that I have done here at AWI on the "NAOSIM"  
> 1/4th degree grid, shown are monthly means effective thickness,  
> concentration, "salt flux", and a histogram of ice thickness  
> differences after 10 years of integration. It's immediately clear  
> that thsice produces more ice and in particular in summer, the ice  
> concentration is higher (which is good, because in general, the  
> summer ice concentration is underestimated by a lot of models that  
> get the winter concentration right, see AOMIP paper C04S11 in JGR by  
> Johnson et al, 2007, doi:10.1029/2006JC003690). Also the ice extend  
> is larger in thsice, and may require some tuning. I don't understand  
> why the "salt flux" is so different, maybe I am not plotting the  
> same thing. Also, with thsice, there are problem near the open  
> boundary in the Bering Strait/Sea, which I don't want to investigate  
> now.
> In general, the thsice seems to work nicely (although I has a  
> significant portion of code that does not vectorize and thus is a  
> pain in the ... for me, I'll look into that sometime), and I hope  
> that Dimitris will get similar results. However there are always  
> plenty of
> BBerr - Bug: IceT(1) > Tmlt 239  32  1  1 -5.376776E-02 -5.400000E-02
> which I choose to ignore.
>
> One problem, which I have not yet solved (and I guess that Dimitris  
> is also struggling with), is that the model crashes after 1 timestep  
> when I specify initial conditions like this:
>> thSIceFract_InitFile='ice_conc.bin',
>> thSIceThick_InitFile='ice_thick.bin',
> Maybe I am overlooking something here? I faintly remember that I  
> need to specify not only thickness and concentration, but also some  
> initial values for entalphy and snow? Is that true?
>
> Martin
>
> On 29 Apr 2008, at 16:36, Martin Losch wrote:
>
>> Hi there,
>>
>> I just had a chat with K+K (Frank Kauker/Michael Karcher) who work  
>> on the Arctic with NAOSIM. They have made a lot of progress in  
>> generating the adjoint to this model, so that they can look at real  
>> science questions. Frank show me an extended abstract where they  
>> investigate the probably causes of the Sept, 2007 ice minimum with  
>> adjoint sensitivities back to March 2007; as far as I could see,  
>> it's very nice work, in particular, because it addresses a real  
>> question. I see this as an incentive to once again push our efforts  
>> (and encourage Patrick to write up his adjoint stuff).  
>> Unfortunately, we have been held up by various problems, which I am  
>> trying to summarize:
>> General: I have updated some figures (JFMuv_*) to reflect the  
>> latest runs, I also cleaned up the figs directory on skylla  
>> (removed old stuff, that we no longer use)
>> - Section 1: Needs a lot of work, maybe Chris can have a look at it?
>> - Section 2: Is basically done, except for small bits and details  
>> on THSICE, the latter I hope Jean-Michel can provide. I suggest  
>> that we use this section to collect all information on the model  
>> and then cut later.
>> - Section 3: forward integrations: Dimitris and I have finally  
>> converged on a set of experiments to analyse, most of which have  
>> been done (by D.) but in particular some of the EVP runs are not  
>> there, yet. I can't continue with section 3.3 unless they are done.
>> - Section 3: I don't know what the status of section 3.1 (bi-polar  
>> sea ice from global integration) is. Since I have now a global  
>> integration, too, I could use data from that integration to plot  
>> ice fields. Dimitris, what's your status here? Do you want me to do  
>> this (I have no idea what to plot here, seasonal averages?)?
>> - Section 4: Patrick, my last email exchange with you was almost a  
>> month ago, when you wanted to rerun some experiments after  
>> adjusting SEAICE_gamma_t or availHeatFrac, in order to compare to  
>> Ian Femty's code/results, what's the status here.
>> - Section 5: (Summary/Conclusions), nothing new so far.
>>
>> what can we do to push this manuscript?
>>
>> Martin
>>
>
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