The ice model dynamics is subcycled ndte times per timestep so that the elastic waves are damped before the next timestep. When the value of ndte is too small, an instability occurs, the model execution stops, and an error message similar to this example is written out to the log file:
mpdata phi = -0.122707896960329384E-05 n = 5 (shr_sys_abort) ERROR: (mpdata) transport unstable (shr_sys_abort) WARNING: calling mpi_abort() and stopping
To get around this problem, increase the value of ndte in the namelist. Reasonable values of this parameter are discussed in section 4.2. The model run can be restarted from the last set of restart files that were written before the execution halted.