[MITgcm-support] Re: problem with obcs package

[Matthew Mazloff]

Hi Suneet,

eta_max is zero because eta becomes negative everywhere but at obcs  
it is set to 0.  then the statistics show max sea level is 0.  Your  
basin is losing fluid

don't worry about salt_min....its probably reading that there is a  
value of salt = 0 over a land point...no problem...these are just  
global statistics.  if you have a value of S=0 and it is not in the  
top few levels the model would probably blow up (become unstable)  
from such strong convection...or at least you should notice it in the  
solution

-matt




On Aug 28, 2008, at 5:54 PM, Suneet Dwivedi wrote:

> Hi Everybody,
>
> Lately i am experiencing some problem with the obcs package.
>
> When I use obcs package, somehow value of few model dynamical
> variables ( "dynstat_eta_max" and  "dynstat_salt_min") is becoming
> zero. When the model starts, moniter/diagnostics shows value of
> "dynstat_eta_max" for the first 6 steps; from 7th step onwards it
> becomes zero, whereas, "dynstat_salt_min" remains zero from first step
> onwards. Model results at 7th step are as follows:
> ---------------------------------------------------------------------- 
> -----------------------------------------------------------
> (PID.TID 0000.0001) //  
> =======================================================
> (PID.TID 0000.0001) // Begin MONITOR dynamic field statistics
> (PID.TID 0000.0001) //  
> =======================================================
> (PID.TID 0000.0001) %MON time_tsnumber                 
> =                     7
> (PID.TID 0000.0001) %MON time_secondsf                =    
> 1.4000000000000E+03
> (PID.TID 0000.0001) %MON dynstat_eta_max              =    
> 0.0000000000000E+00
> (PID.TID 0000.0001) %MON dynstat_eta_min              =   
> -2.6433571736246E-01
> (PID.TID 0000.0001) %MON dynstat_eta_mean             =   
> -1.1940164622399E-01
> (PID.TID 0000.0001) %MON dynstat_eta_sd               =    
> 7.1493893173745E-02
> (PID.TID 0000.0001) %MON dynstat_eta_del2             =    
> 1.3422710779062E-03
> (PID.TID 0000.0001) %MON dynstat_uvel_max             =    
> 5.4667687177828E-01
> (PID.TID 0000.0001) %MON dynstat_uvel_min             =   
> -6.1052637074417E-01
> (PID.TID 0000.0001) %MON dynstat_uvel_mean            =   
> -3.8818565367701E-03
> (PID.TID 0000.0001) %MON dynstat_uvel_sd              =    
> 2.1475399015986E-02
> (PID.TID 0000.0001) %MON dynstat_uvel_del2            =    
> 4.5939393936678E-04
> (PID.TID 0000.0001) %MON dynstat_vvel_max             =    
> 5.5877684713746E-01
> (PID.TID 0000.0001) %MON dynstat_vvel_min             =   
> -5.7746696227642E-01
> (PID.TID 0000.0001) %MON dynstat_vvel_mean            =    
> 1.5640213744729E-03
> (PID.TID 0000.0001) %MON dynstat_vvel_sd              =    
> 6.9891248930834E-03
> (PID.TID 0000.0001) %MON dynstat_vvel_del2            =    
> 5.8174915728512E-04
> (PID.TID 0000.0001) %MON dynstat_wvel_max             =    
> 2.8444881692966E-02
> (PID.TID 0000.0001) %MON dynstat_wvel_min             =   
> -1.0068659305734E-01
> (PID.TID 0000.0001) %MON dynstat_wvel_mean            =    
> 3.4574159035878E-05
> (PID.TID 0000.0001) %MON dynstat_wvel_sd              =    
> 2.1005775162501E-03
> (PID.TID 0000.0001) %MON dynstat_wvel_del2            =    
> 1.0139161400288E-04
> (PID.TID 0000.0001) %MON dynstat_theta_max            =    
> 8.1588867498623E+00
> (PID.TID 0000.0001) %MON dynstat_theta_min            =   
> -4.3318131748826E-01
> (PID.TID 0000.0001) %MON dynstat_theta_mean           =    
> 1.3478641795650E+00
> (PID.TID 0000.0001) %MON dynstat_theta_sd             =    
> 1.1534690593063E+00
> (PID.TID 0000.0001) %MON dynstat_theta_del2           =    
> 6.1697913750926E-03
> (PID.TID 0000.0001) %MON dynstat_salt_max             =    
> 3.6128621210312E+01
> (PID.TID 0000.0001) %MON dynstat_salt_min             =    
> 0.0000000000000E+00
> (PID.TID 0000.0001) %MON dynstat_salt_mean            =    
> 3.4625531293968E+01
> (PID.TID 0000.0001) %MON dynstat_salt_sd              =    
> 3.7266776584207E-01
> (PID.TID 0000.0001) %MON dynstat_salt_del2            =    
> 1.2677082847302E-03
> ---------------------------------------------------------------------- 
> ------------------------------------------------------
> When i don't use obcs, no such problem occurs and I get the correct
> values of all the model variables.
>
> STDOUT file of such a model run is attached herewith for your perusal.
> Please help me resolve the problem.
>
> Thanks,
> Suneet<STDOUT.0000>