[MITgcm-support] ice layer modeling

[Elja Huibregtse]

Dear all,

Currently, I am trying to model a thick (10 kilometers) ice layer on top of an ocean of about 100 kilometers deep (to simulate Jupiter's moon Europa). I implemented the tidal force induced by Jupiter both in the ocean equations (external_forcing.f) and in the ice-layer equations (seaice_lsr.f). 

Sooner or later, the model becomes unstable and 'blows up'. The errors are like:

WARNING: r*FacW < hFacInf at       3 pts : bi,bj,Thid,Iter=   1   1   1      7266
 e.g. at i,j=  17  29 ; rStarFac,H,eta =**********  1.050000E+05  1.087561E+10 -2.871467E+10
STOP in CALC_R_STAR : too SMALL rStarFacW !
WARNING: r*FacS < hFacInf at       2 pts : bi,bj,Thid,Iter=   1   1   1      7266
 e.g. at i,j=  15  30 ; rStarFac,H,eta =**********  1.050000E+05 -1.720477E+10  2.505553E+09
STOP in CALC_R_STAR : too SMALL rStarFacS !
WARNING: r*FacC < hFacInf at       2 pts : bi,bj,Thid,Iter=   1   1   1      7266
 e.g. at i,j=  17  29 ; rStarFac,H,eta =**********  1.050000E+05 -2.871467E+10
STOP in CALC_R_STAR : too SMALL rStarFacC !

Initially, I assume a thick ice layer, which will of course cause (some) artificial behavior.
I tried to force Europa with only 10% of the total forcing. This went well. My intention was to gradually increase the forcing (by using restarts), to prevent too much artificial behavior. However, after increasing the forcing (up to 30%) the model became unstable again.

Do you have some suggestions how to improve my model? Is there maybe something really  trivial I did not include? 
Furthermore, is the ice layer modeled on top of the ocean or is the top ocean layer replaced by the ice-layer?

I attached the data file. 

I really appreciate your help!

Thanks in advance,


Elja

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