[MITgcm-devel] depressed Eta and sIceLoad

[Martin Losch]

Hi Jinlun et al.,

please have a quick look at 10day averages of HEFF and HSNOW in July  
and January (after 100 years) in
http://mitgcm.org/~mlosch/ice_iter72360.png (Jul)
http://mitgcm.org/~mlosch/ice_iter72020.png (Jan)
run22 is without advection of snow (both runs are with evap*(1- 
area)), run26 is with advection of snow. Unfortunately, the runs are  
not exactly comparable because I had to use a 1-order upwind scheme  
for advection the snow, so that run26 uses the 1-order upwind scheme  
(for HSNOW, HEFF and AREA) and run22 the traditional 2nd order  
central differences scheme (but only for HEFF and AREA), no  
"flooding" in either case. What you see is that the advection reduces  
the amplitudes of the snow be a factor of 100, but maybe that's just  
the 1-order upwind scheme? Also the snow is in areas where it  
shouldn't be.
Not shown: My (it's not mine, but as opposed to Jinlun's suggestion)  
simple flooding scheme removes this snow at the "expense" of much  
increased ice thicknesses, Jinlun's scheme reduces the snow heights  
even further (I only have 10year yet, but it's already <20cm as  
opposed to <50cm in "my" runs), and the ice thickness is not  
increased as much. Also the freshwater flux into the ocean appears to  
be reduced (higher surface salinities) so that as a first conclusion  
I would say that Jinlun's fix appears to be quite appropriate (as  
opposed to mine). More analyses to follow.

Martin


On 24 Oct 2006, at 23:19, Jinlun Zhang wrote:

> Hi Martin,
> Advecting snow is certainly better than not, but I am not sure if  
> it would solve the problem of getting big numbers for snow.
> Jinlun
>
> mlosch at awi-bremerhaven.de wrote:
>
>> Hi Jinlun,
>> thanks, I'll try this out tomorrow. What about advecting HSNOW?  
>> Why can that be neglected?
>>
>> Martin
>>
>> Martin Losch
>> Alfred Wegener Institute Postfach 120161, 27515 Bremerhaven,  
>> Germany; Tel./Fax: ++49(0471)4831-1872/1797
>>
>>
>>
>> ----- Original Message -----
>> From: Jinlun Zhang <zhang at apl.washington.edu>
>> Date: Tuesday, October 24, 2006 7:56 pm
>> Subject: Re: [MITgcm-devel] depressed Eta and sIceLoad
>>
>>
>>> Dimitris and all,
>>> The ncep precip in Antarctic is way too much, but I have moidfied  
>>> growth.F  to, hopefully, improve things a little bit. The  
>>> modification would allow the ocean to melt  the left-over snow  
>>> when ice is gone (seach jz for the modi's in the code) . See if  
>>> there is any improvement ot of it.
>>> Jinlun
>>>
>>> Dimitris Menemenlis wrote:
>>>
>>>
>>>> It looks bad:
>>>> http://ecco2.jpl.nasa.gov/data2/cube/cube38/pickup/HSNOW.jpg
>>>> 20 to 60 m of snow over open water.  This is after a 12-year
>>>> integration on the cubed sphere.
>>>>
>>>> Dimitris
>>>> _______________________________________________
>>>> MITgcm-devel mailing list
>>>> MITgcm-devel at mitgcm.org
>>>> http://mitgcm.org/mailman/listinfo/mitgcm-devel
>>>>
>>> -- 
>>>
>>> Jinlun Zhang
>>> Polar Science Center, Applied Physics Laboratory
>>> University of Washington, 1013 NE 40th St, Seattle, WA 98105-6698
>>>
>>> Phone: (206)-543-5569;  Fax: (206)-616-3142
>>> zhang at apl.washington.edu
>>> http://psc.apl.washington.edu/pscweb2002/Staff/zhang/zhang.html
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
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