[MITgcm-support] Negative Salinities

[Martin Losch]

Sergio,

sorry, I don't have a clue. If you want, you can send me your entire 
setup, that is, the version of the code (which cvs checkpoint), plus 
all files that you have modified (find out with cvs -qn update -r 
your_checkpoint_tag), and, of course you data files (I assume that, 
because you don't have any input files this package shouldn't be too 
large). I could then have a look. My email: mlosch at awi-bremerhaven.de

Martin

On Tuesday, May 25, 2004, at 06:31 PM, Sergio Jaramillo wrote:

> Hi Martin,
>
> Thanks a lot for your comments. I noticed that the CPP-flag does not 
> improve anything for me. The problem does occur after the first time 
> step, but I wouldn't think that it has anything to do with my forcing 
> fields as I haven't changed this from my old runs, and I don't use any 
> salinity filed as an input. I force the model with a body force that I 
> wrote into external_forcing.F. I will put here part of my data file in 
> case anyone sees something wrong and could give me any advice:
>
> # ====================
> # | Model parameters |
> # ====================
> #
> # Continuous equation parameters
>  &PARM01
>
>  Tref =  14.1283,  11.9377,  9.89651,    8.154,  6.71021,  
>           5.6647,  4.91792,  4.32048,  3.72305,  3.02605, 
>           2.32905,   1.7814,  1.18397, 0.486969, -0.110463,
>          -0.558536,  -1.0564, -1.70361, -2.35083, -2.84869,
>          -3.29676, -3.69505, -4.19291, -4.69077, -5.18863,
>          -5.58691,  -5.9852, -6.28392,  -6.6822, -7.18006, 
>          -7.92685, -8.92257,
>  sRef= 32*35.,
>  viscAz=1.E-6,
>  viscAh=1.E-6,
>  no_slip_sides=.TRUE.,
>  no_slip_bottom=.TRUE.,
>  bottomDragLinear=0.,
>  viscA4=0.E12,
>  diffKhT=1.E-6,
>  diffKzT=1.5E-9,
>  diffKhS=1.E-6,
>  diffKzS=1.5E-9,
>  tempAdvScheme= 33,
>  saltAdvScheme= 33,
>  saltForcing= .FALSE.,
>  tempForcing=.FALSE.,
>  staggerTimeStep=.TRUE.,
>  exactConserv=.TRUE.,
>  f0=0.52,
>  beta=0.E-11,
>  tAlpha=2.E-3,
>  rhonil=1.0043E3,
>  sBeta =0.E-4,
>  gravity=9.81,
>  gBaro=9.81,
>  rigidLid=.FALSE.,
>  implicitFreeSurface=.TRUE.,
>  eosType='LINEAR',
>  hFacMin=0.2,
>  nonHydrostatic=.FALSE.,
>  readBinaryPrec=64,
>  globalFiles=.FALSE.,
>  vectorInvariantMomentum=.FALSE.,
>  &
>
>
> Sergio Jaramillo
> UBC
>
>
>
> Sergio,
>
> no use in defining this CPP-flag, it will not solve your problem. This
> routine raises a flag/warning, if it finds one or more negative
> salinity values in the current horizontal slab and resets the negative
> values to zero.
> But if you have salinities of +/-1.5e+139, your problem is likely to be
> something completely different. If this happens after one or two time
> steps, I am guessing, that there are some memory issues, such as a
> double precision field is read into a single precision variable or vice
> versa (for example, your forcing fields).
>
> Martin
>
> On Saturday, May 22, 2004, at 02:47 AM, Sergio Jaramillo wrote:
>
>
>
> Dear MITgcm support,
>
> I just noticed that the salinity field that I get from my runs is
> going negative like -1.5e+139!. Why could this be? I only input
> sRef=32*35, and I do all the stratification using the temperature
> profile. I also have set sBeta=0.  Also I didn't have this problem
> before , when I used an older version of the model (like a year ago,
> v1.15 according to find_rho.F ).
>
> Finally I find this in find_rho.F:
>
> #ifdef CHECK_SALINITY_FOR_NEGATIVE_VALUES
>      CALL LOOK_FOR_NEG_SALINITY( bi, bj, iMin, iMax, jMin, jMax,  k,
>     &     sFld, myThid )
> #endif
>
> Should I define this in CPP_OPTIONS.h?
>
>
> Thanks a lot,
>
> Sergio Jaramillo
> UBC
>
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>
>
> Martin Losch // mailto:mlosch at awi-bremerhaven.de
> Alfred-Wegener-Institut für Polar- und Meeresforschung
> Postfach 120161, 27515 Bremerhaven, Germany
> Tel./Fax: ++49(471)4831-1872/1797
> http://www.awi-bremerhaven.de/People/show?mlosch
>
>
>
>
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