[RegCNET] Model not working after a particular time

[Dilip Ganguly]

Hello,

I am trying to perform my simulation with a horizontal resolution of 90 
km. Initially I used the the following time steps as mentioned in the 
regcm user manual
radfrq  =    30.,
 abemh   =    18.,
 abatm   =   900.,
 dt      =   225.,

Now I increased the time steps dt to 300 and restarted my simulations. 
However still I am facing similar problem. Simulation starts and then it 
hangs. I got the following message on my screen

 ******* OPENING NEW OUTPUT FILES:  2004020100
 OPENING NEW OUT FILE: output/ATM.2004020100
 OPENING NEW BAT FILE: output/SRF.2004020100
 OPENING NEW RAD FILE: output/RAD.2004020100
 BATS variables written at   2004020103   180.000000000000
     at day =   92.1562, ktau =      11950 :  1st, 2nd time deriv of ps =  
0.30840E-04 0.12518E-06,  no. of points w/convection =  143
 OUT-history written date =    2004020106.00000
 BATS variables written at   2004020106  0.000000000000000E+000
 Writing rad fields at ktau =        11976  2004020106
 BCs are ready from   2004020106   to   2004020112
     at day =   92.3299, ktau =      12000 :  1st, 2nd time deriv of ps =  
NaN        NaN        ,  no. of points w/convection =    0

--------------------------------------------------------------------------

Can anyone suggest me proper time steps (for horizontal resolution of 90 
km) to avoid this kind of problem possibly due to convective instabilities 
as told by Jagadish.

Thanks.

Dilip.

On Wed, 27 Dec 2006, jagadish karmacharya wrote:

> Dear Dilip,
> 
> I used to face similar problem. I think this error arise due to convective instability. A common work around is to decrease the time step and restart the model. If run goes well you can stop the model after few days run and restart it with original time step if you want to lose computational time.
> 
> Wish you Happy New Year!
> Jagadish 
> 
> Dilip Ganguly <dganguly at prl.res.in> wrote: Hello everyone,
> 
> My Greetings to you all on Christmas!
> 
> I wanted to run RegCM3 for the year 2004 over the south Asian domain. I 
> choose an initial spin up time of two months. That means I started my 
> simulations from 1st Nov. 2003. Simulations started normally and worked 
> upto 1st February 2004. However after this it started showing problem in 
> calculating 1st and 2nd time deriv of ps and I was getting following 
> message on the screen
> 
>      at day =   93.0286, ktau =      12300 :  1st, 2nd time deriv of ps =  
> NaN        NaN        ,  no. of points w/convection =    0
>  BATS variables written at   2004020203   180.000000000000
>      at day =   93.1589, ktau =      12350 :  1st, 2nd time deriv of ps =  
> NaN        NaN        ,  no. of points w/convection =    0
>  OUT-history written date =    2004020206.00000
>  BATS variables written at   2004020206  0.000000000000000E+000
>  Writing rad fields at ktau =        12384  2004020206
>  BCs are ready from   2004020206   to   2004020212
>      at day =   93.2891, ktau =      12400 :  1st, 2nd time deriv of ps =  
> NaN        NaN        ,  no. of points w/convection =    0
> 
> ---------------------------------------------------------------------
> At this point I stopped the model and restarted it. However the problem 
> is not solved I am getting following message again
> 
>  ******* OPENING NEW OUTPUT FILES:  2004020200
>  OPENING NEW OUT FILE: output/ATM.2004020200
>  OPENING NEW BAT FILE: output/SRF.2004020200
>  OPENING NEW RAD FILE: output/RAD.2004020200
>      at day =   93.0286, ktau =      12300 :  1st, 2nd time deriv of ps =  
> NaN        NaN        ,  no. of points w/convection =    0
> 
> --------------------------------------------------------------------
> 
> Can anyone tell me why is this problem arising and how to overcome it?
> 
> Thanks in advance.
> 
> Dilip. 
>   
>      ---------------------------------------------------------------------
>         DILIP GANGULY                               
>         Postdoctoral Fellow                     
>         Space And Atmospheric Sciences Division      
>         Physical Research Laboratory                
>         Ahmedabad 380009
>  Gujarat, India
>         Phone: +91 79 26314558 (Laboratory)    
>                +91 79 26300505 (Hostel)
>  Fax:   +91 79 26314659
>  Alternate Email: ganguly.dilip at gmail.com          
>             Visit me at   http://www.prl.res.in/~dganguly
>      ---------------------------------------------------------------------
> 
> 
> 
> 
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Dilip. 
  
     ---------------------------------------------------------------------
        DILIP GANGULY                               
        Postdoctoral Fellow                     
        Space And Atmospheric Sciences Division      
        Physical Research Laboratory                
        Ahmedabad 380009
	Gujarat, India
        Phone: +91 79 26314558 (Laboratory)    
               +91 79 26300505 (Hostel)
	Fax:   +91 79 26314659
	Alternate Email: ganguly.dilip at gmail.com          
            Visit me at   http://www.prl.res.in/~dganguly
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