[MITgcm-support] CS64 grid

[Anthony Coletti]

Hi Martin,

I used the CCSM4.0 LGM control values which seem to be on par with ERA data - so I assume that the forcing fields are reasonable for LGM.
I integrate for about 100 - 150 years before I start getting really thick ice - ~200m.  However, the thickness seems to progress exponentially as I go through the integration.

MAX_HEFF used to be the capping term that could be put in data.seaice but I believe that has been removed.

Can I use SEAICE_deltaTdyn = # in my data.seaice file to perhaps lower my time step and avoid a similar situation?

Anthony

Anthony J. Coletti
Climate System Research Center
Department of Geosciences
Morrill Building
611 N. Pleasant Street
233 Morrill Science Center
University of Massachusetts-Amherst
paleoclimate.org
Email: ajcolett at geo.umass.edu
http://blogs.umass.edu/ajcolett/

“For me, I am driven by two main philosophies: know more today about the world than I knew yesterday and lessen the  suffering of others. You'd be surprised how far that gets you.” ― Neil deGrasse Tyson




On Feb 10, 2014, at 11:09 AM, Martin Losch <Martin.Losch at awi.de> wrote:

> The time step should be OK for this configuration.
> 
> What about your forcing? Is it too cold? Not enough incoming radiation? What do expect when you apply your forcing?
> How long do you need to integrate before this happen?
> 
> Ultrathick ice appears usually in “corners” or “embayments” that have little connection to the rest of the domain, geometrically or dynamically, so that ice get’s stuck and keeps growing. For these cases capping in a thermodynamically inconsistent way is a convenient way out (HEFF=MIN(HEFF,someMaxValue), but that’s not implementend anymore, is it?
> 
> Martin
> 
> 
> On Feb 10, 2014, at 4:59 PM, Anthony Coletti <ajcolett at geo.umass.edu> wrote:
> 
>> Is the sea ice dynamics time step located in data file or data.seaice?
>> 
>> These are the time steps in data file:
>> 
>> deltaTmom = 1200.,
>> deltaTtracer = 86400.,
>> deltaTfreesurf = 86400.,
>> deltaTclock = 86400.,
>> 
>> 
>> Anthony
>> 
>> 
>> 
>> Anthony J. Coletti
>> Climate System Research Center
>> Department of Geosciences
>> Morrill Building
>> 611 N. Pleasant Street
>> 233 Morrill Science Center
>> University of Massachusetts-Amherst
>> paleoclimate.org
>> Email: ajcolett at geo.umass.edu
>> http://blogs.umass.edu/ajcolett/
>> 
>> “For me, I am driven by two main philosophies: know more today about the world than I knew yesterday and lessen the  suffering of others. You'd be surprised how far that gets you.” ― Neil deGrasse Tyson
>> 
>> 
>> 
>> 
>> On Feb 10, 2014, at 10:53 AM, Dimitris Menemenlis <dmenemenlis at gmail.com> wrote:
>> 
>>> Do you use 1-day time steps for sea ice dynamics?
>>> With such large time steps, I am guessing that LSR
>>> solver would be very inaccurate, if it works at all.
>>> 
>>> Dimitris Menemenlis
>>> 
>>> On Feb 10, 2014, at 7:47 AM, Anthony Coletti <ajcolett at geo.umass.edu> wrote:
>>> 
>>>> Thanks Dimitris!
>>>> 
>>>> One other question (I also CC’d the MITgcm community).  Does anyone have any idea why I am growing +200m thick sea ice in the Arctic?  I am using pkg/seaice.  I originally thought it may have been my time step blowing up, but I lowered it from 2 days down to 1 day and I still get crazy amounts of sea ice.  This creates r*starr calculation errors.  I am running a CS32x6x32x15 grid - so it is quite coarse.
>>>> 
>>>> Thanks!
>>>> 
>>>> Anthony
>>> 
>> 
>> _______________________________________________
>> MITgcm-support mailing list
>> MITgcm-support at mitgcm.org
>> http://mitgcm.org/mailman/listinfo/mitgcm-support
> 
> 
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mitgcm.org/mailman/listinfo/mitgcm-support

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mitgcm.org/pipermail/mitgcm-support/attachments/20140210/d7c2a652/attachment-0001.htm>