The following behavior is obtained with configuration OFF_MY_TRC & NEMO v3.4

I used several tracers without sms and sbc (i.e. E-P forced to 0). Results are reported for tracers 1 and 6. Tracer 1 is initialized homogeneously (1 everywhere), tracer 6 has initial vertical and horizontal gradients.

Activating the isopycnal diffusion results in a rapid divergence of concentrations.

The results presented hereafter are obtained every 5 years. The situation is bad from the start for tracer 6, and degrades severely for tracer 1 after 15 years. Activating the correction of negative values does not help.

Ch. Ethé obtained exactly the same behavior on a different computer with his own version of the model.

Such behavior does not happen with horizontal diffusion (though conservation is not obtained, see #1134).

Many thanks for helping resolve this. Anne

curie71:EXP00> grep drift ocean.output-TESTIS01

tracer nb : 1 name : H2Ot mean : 0.1000000000E+01 min : 0.9999999996E+00 max : 0.1000000010E+01 drift : 0.2666078212E-09 % tracer nb : 6 name : ASEL mean : 0.3470195362E+02 min : -0.5063662861E+01 max : 0.1075321689E+04 drift : -0.1702945242E-03 %

tracer nb : 1 name : H2Ot mean : 0.1000000000E+01 min : 0.9999972291E+00 max : 0.1000072516E+01 drift : 0.5318454538E-09 % tracer nb : 6 name : ASEL mean : 0.3470156440E+02 min : -0.2963918080E+06 max : 0.7757576421E+07 drift : -0.1291890798E-02 %

tracer nb : 1 name : H2Ot mean : 0.1000000000E+01 min : 0.9793435102E+00 max : 0.1540584520E+01 drift : -0.1919518417E-08 % tracer nb : 6 name : ASEL mean : 0.3179551460E+02 min : -0.2209776402E+10 max : 0.5783029664E+11 drift : -0.8375589448E+01 %

tracer nb : 1 name : H2Ot mean : 0.9999997975E+00 min : -0.1529883352E+03 max : 0.4030905900E+04 drift : -0.2025247416E-04 % tracer nb : 6 name : ASEL mean : -0.2163199347E+05 min : -0.1647326323E+14 max : 0.4311086329E+15 drift : -0.6243642309E+05 %

tracer nb : 1 name : H2Ot mean : 0.9984901557E+00 min : -0.1147938827E+07 max : 0.3004181861E+08 drift : -0.1509844287E+00 % tracer nb : 6 name : ASEL mean : -0.1615190996E+09 min : -0.1228035546E+18 max : 0.3213793881E+19 drift : -0.4654460120E+09 %

tracer nb : 1 name : H2Ot mean : -0.1025546557E+02 min : -0.8557569272E+10 max : 0.2239533200E+12 drift : -0.1125546557E+04 % tracer nb : 6 name : ASEL mean : -0.1204079821E+13 min : -0.9154660386E+21 max : 0.2395793153E+23 drift : -0.3469769406E+13 %

tracer nb : 1 name : H2Ot mean : -0.8390533729E+05 min : -0.6379427751E+14 max : 0.1669509155E+16 drift : -0.8390633729E+07 % tracer nb : 6 name : ASEL mean : -0.8976077174E+16 min : -0.6824542420E+25 max : 0.1785996565E+27 drift : -0.2586615724E+17 %

tracer nb : 1 name : H2Ot mean : -0.6254981977E+09 min : -0.4755684369E+18 max : 0.1244572225E+20 drift : -0.6254981987E+11 % tracer nb : 6 name : ASEL mean : -0.6691413647E+20 min : -0.5087504864E+29 max : 0.1331410320E+31 drift : -0.1928249437E+21 %

tracer nb : 1 name : H2Ot mean : -0.4662913545E+13 min : -0.3545229243E+22 max : 0.9277936686E+23 drift : -0.4662913545E+15 % tracer nb : 6 name : ASEL mean : -0.4988261100E+24 min : -0.3792592111E+33 max : 0.9925290318E+34 drift : -0.1437455844E+25 %

tracer nb : 1 name : H2Ot mean : -0.3476071197E+17 min : -0.2642868915E+26 max : 0.6916441443E+27 drift : -0.3476071197E+19 % tracer nb : 6 name : ASEL mean : -0.3718608669E+28 min : -0.2827270991E+37 max : 0.7399025409E+38 drift : -0.1071582994E+29 %

curie71:EXP00>

A critical bug appears in offline because, the new surface cells - e12t,e12u, etc...- used in lateral diffusion routines at not defined when using an offline configuration

When trying to run the AMM12 with XIOS and the latest merge code (dev_MERGE_2013) I get bizarre failures.

Wihtout key_iomput the model runs fine for 10 days.

With key_iomput things fail. Using the standard iodef.xml file (which I have just recently amended to fit the new XIOS formatting requirements) from the CONFIG/AMM12/EXP00 directory the model should output both daily and every 5 days. It runs until one timestep before the end of the fifth day and gives the following error message; xios/src/output/onetcdf4.cpp', line 79 -> [ status = -60 ] NetCDF: Numeric conversion not representable Output files are created for both 1d and 5d, but when trying to view them or dump them an error message appears stating that they aren't netcdf format.

Have I 'fixed' the file format incorrectly, or is there something else going on?