[MITgcm-support] changes in seaice default behaviour?

[Christoph Voelker]

Dear all,

I have problems in continuing a global ocean run for the last glacial 
maximum that I suspect are related to changes in the default behaviour 
of the seaice module in checkpoint 67d.

I used to run the model with the somewhat outdated version checkpoint 
66f over 3000 years. Then I switched to the newer code version, 
recompiled and wanted to continue the run for another 1000 years or so. 
What then happens is that - without having changed anything in my 
data.seaice and SEAICE_OPTIONS.h - the model starts accumulating very 
thick ice around Antarctica; ice tends to build up to typical ice 
thicknesses of more that 15 m where I previously only had 2 m or so. 
Eventually the model crashes and I believe it has to do with seaice+snow 
reaching a thickness of more than 60m in a few points.

Can anyone perhaps tell me which of the new defaults in the seaice 
parameters might me responsible and suggest what I could change?

I must add to this that I run a scenario where I force the model with 
atmospheric output (temperature, winds etc) from a coupled ocean 
atmosphere climate model run for the last glacial, so I get rather cold 
air temperatures around Antarctica. For that reason my data.seaice has 
already a few settings to prevent a too strong seaice buildup:

# SEAICE parameters
  &SEAICE_PARM01
   SEAICEwriteState   = .TRUE.,
   SEAICE_initialHEFF = 0.0,
   HO = 1.,
   SEAICEuseFlooding = .true.,
   SEAICEadvSnow     = .true.,
   SEAICEpressreplfac = 0.,
   SEAICE_clipVelocities = .false.,
   SEAICEadvScheme   = 33,
   SEAICE_no_slip    = .false.,
# SEAICE_deltaTevp  = 360.,
  &

Cheers, Christoph

-- 
Christoph Voelker
Alfred Wegener Institute
Helmholtz Centre for Polar and Marine Research
Am Handelshafen 12
27570 Bremerhaven, Germany
e: Christoph.Voelker at awi.de
t: +49 471 4831 1848