[MITgcm-devel] problem with 59c

[Dimitris Menemenlis]

Martin, here is what I know about 59c as of this morning:

1. In all cases crash occurs because sea ice thickness in some grid point goes 
through the roof.  With dynamics, crash occurs within 5 days near Antarctica. 
Without dynamics, crash occurs in the Arctic after about 10 days.  But as noted 
in previous e-mail, the Arctic-only CS510 configuration with open boundaries and 
rstar off runs fine with latest code.

2. Code checked out on May 24 runs fine.

3. Code checked out on May 26 crashes.

Differences between May 24 and May 26 is here:
http://ecco2.jpl.nasa.gov/data1/arctic/diff_may26_may24.orig
The files that have changed between two versions are

Index: doc/tag-index
Index: pkg/gmredi/gmredi_calc_tensor.F
Index: pkg/seaice/seaice_dynsolver.F
Index: pkg/seaice/seaice_lsr.F
Index: pkg/seaice/seaice_readparms.F
Index: tools/genmake2
Index: tools/build_options/SUPER-UX_SX-8_sxf90+mpi_awi
Index: tools/build_options/linux_ia64_ifort+mpi_altix_gfdl

By elimination, since I do not use gmredi and since code crashes even with 
SEAICEuseDYNAMICS=.FALSE., the only changes that seem to possibly matter are

Index: pkg/seaice/seaice_dynsolver.F
===================================================================
172,176d171
<          ENDDO
<         ENDDO
<
<         DO j=1-Oly,sNy+Oly
<          DO i=1-Olx,sNx+Olx
181c176
<           ZMIN(I,J,bi,bj)=0.0 _d 0
---
 >           ZMIN(I,J,bi,bj)=4.0 _d +08

Index: pkg/seaice/seaice_readparms.F
===================================================================
267c267,268
<        IF ( SEAICE_elasticParm .LE. 0. _d 0 ) THEN
---
 >        IF ( SEAICE_elasticParm .LE. 0. _d 0 .OR.
 >      &      SEAICE_elasticParm .GT. 1. _d 0 ) THEN
269c270
<      &       'SEAICE_elasticParm must greater than 0.'
---
 >      &       'SEAICE_elasticParm must greater than 0 and less than 1.'

But why should above changes matter in any way when SEAICEuseDYNAMICS=.FALSE.? 
Maybe I am chasing two separate bugs, and the thermodynamics-only crash is not 
related?

More later, D.