[MITgcm-devel] depressed Eta and sIceLoad

Tue Oct 24 12:24:56 EDT 2006

This one looks like it might have 25m of snow, but not 200m!

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-Baylor

On Oct 24, 2006, at 12:15 PM, Jean-Michel Campin wrote:

> Hi Martin,
>
> I don't have any problem with snow when I use pkg thSIce
> (since it get converted into ice if below sea-level).
> But with pkg seaice, I had to modify the pickup
> of the cs-510 run (just remove the exces of snow)
> to turn on the ice-loading, because there was too much snow
> (max ~ 200m).
> The thing that was missing in pkg seaice, was a diagnostic for
> the snow thickness.
>
> Do you still have the low SSH with the flooding added to
> pkg/seaice (since it's not currently in, right ?) ?
>
> Jean-Michel
>
> On Tue, Oct 24, 2006 at 03:51:10PM +0200, Martin Losch wrote:
>> EVAP should definitely be fixed (will change results!)
>>
>> Please have a look at the snow. I have now implemented both advection
>> of snow and flooding (btw, the flooding alogrithm is part of
>> thsice_calc_thickn.F) and the excessive snow (without ice!) and
>> consequently the Eta depression goes away in first tests (I have not
>> tried to use advection of snow without flooding and vice versa). I
>> don't see why this problem should be particular to me (as Jean-Michel
>> pointed out that he also got a lot of snow), so please check your
>> runs. I use CORE (ncep) precipitation with reasonable values so there
>> is no particular reason for the accumulation.
>>
>> Martin
>>
>> On 24 Oct 2006, at 15:31, Patrick Heimbach wrote:
>>
>>>
>>> Martin, DImitris,
>>>
>>> re. EVAP,
>>> the ECCO runs now with sea-ice
>>> show surprising large near-surf. salinity misfits
>>> in the SO, following seasonal ice cycle
>>> and pronounced in Weddell Sea.
>>> So this is very consistent with Martin's finding.
>>> Maybe time to check in the fix?
>>> Don't think we have snow problems though
>>> (although haven't diagnosed anything yet,
>>> but SSH drift with realFreshWater stays bounded).
>>>
>>> -p.
>>>
>>>
>>>
>>> On Tue, 2006-10-24 at 08:20, Martin Losch wrote:
>>>> Dimitris,
>>>> I really think that this will also get rid of your problems in the
>>>> Weddell Sea. As far as I remember you had the problem of too much
>>>> convection, erorsion of stratification and consequently too little
>>>> seaice towards the end of your 10-12year integration. It appears to
>>>> me that EVAP is the culprit, not KPP or missing shelfice water.  
>>>> With
>>>> this bug I had -1.9 all the way to the bottom around Antarctic
>>>> already after 10-20years. After correction of the bug, the
>>>> stratification remains stable for 100year (I haven't run it any
>>>> longer), without any restoring SST/SSS to Levitus.
>>>>
>>>> I still have a problem with seaice though, and that's the snow. Far
>>>> too much snow (100m) that even remains, when the seaice is gone in
>>>> summer. I use all the default parameters.
>>>> Is it a problem that snow is not advected along with ice?
>>>> One could think of a simple flooding algorithm that converts
>>>> submerged snow into ice:
>>>>           hDraft = (HSNOW(I,J,bi,bj)*330. _d 0
>>>>      &             +HEFF(I,J,1,bi,bj)*SEAICE_rhoIce)/1000. _d 0
>>>>           hFlood = hDraft - MIN(hDraft,HEFF(I,J,1,bi,bj))
>>>>           HEFF(I,J,1,bi,bj) = HEFF(I,J,1,bi,bj) + hFlood
>>>>           HSNOW(I,J,bi,bj) = MAX(0. _d 0,HSNOW(I,J,bi,bj)-hFlood/
>>>> SDF)
>>>>
>>>>
>>>> Martin
>>>> On 23 Oct 2006, at 18:50, Dimitris Menemenlis wrote:
>>>>
>>>>> Martin, that's brilliant!  EVAP, as it is computed right now,
>>>>> should definitely be weighted by (ONE-AREA(I,J,2,bi,bj)), that is,
>>>>> set to zero under sea ice.  I agree, I think this is a bug.  Can't
>>>>> wait to give it a try in the 18-km cube. Cheers, Dimitris
>>>>>
>>>>> -- 
>>>>> Dimitris Menemenlis <menemenlis at jpl.nasa.gov>
>>>>> Jet Propulsion Lab, California Institute of Technology
>>>>> MS 300-323, 4800 Oak Grove Dr, Pasadena CA 91109-8099
>>>>> tel: 818-354-1656;  fax: 818-393-6720
>>>>> _______________________________________________
>>>>> MITgcm-devel mailing list
>>>>> MITgcm-devel at mitgcm.org
>>>>> http://mitgcm.org/mailman/listinfo/mitgcm-devel
>>>>
>>>> _______________________________________________
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>>> -- 
>>> Dr Patrick Heimbach | heimbach at mit.edu | http://www.mit.edu/ 
>>> ~heimbach
>>> MIT | EAPS, 54-1518 | 77 Massachusetts Ave | Cambridge, MA 02139,  
>>> USA
>>> FON: +1-617-253-5259 | FAX: +1-617-253-4464 | SKYPE:  
>>> patrick.heimbach
>>>
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>>
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