WRF-LES Error VSPOW

[melpomene23]

Hi,

I am trying to run a real simulation with LES in debug mode, after having run ndown and v_interp, in order to ensure there are o problems before running LES. However I get the following error messages after 8 time steps:

Program received signal SIGFPE: Floating-point exception - erroneous arithmetic operation.

Backtrace for this error:
#0 0x2aaaac2e786f in ???
#1 0x2aaaad033b3f in ???
#2 0x2aaaad0380ca in ???
#3 0x1fbc391 in vspow_
at /glade/.../WRF_DEBUG/WRF/frame/libmassv.f90:371
#4 0x1e615f5 in __module_big_step_utilities_em_MOD_calc_p_rho_phi
at /glade/.../WRF_DEBUG/WRF/dyn_em/module_big_step_utilities_em.f90:1061

I used to get CLF errors as well when I increased vertical levels to 180, from 65, and no matter how much I reduced the time step, it didn't help at all. After reducing vertical levels to 148 in namelist.V_interp, I am getting this error with vspow and no CLF. The current time step is 1.5 seconds for horizontal resolution of 450 m.
I was wondering why I'm getting this error and whether it has anything to do with boundary conditions being shocked. I started the LES domains 12 hours after the initial run in order to avoid that problem and had consulted WRF-help before in order to check the wrfbdy file, and apparently, it looks just fine.
Thanks a lot,

 

[Ming Chen]

Can you build WRF in debug mode (i.e., ./clean -a, then ./configure -D and ./compile em_real). If the model crashed, this option will output the line number in the specific code where the model crashed, from where you can further track down what is wrong.

 

[melpomene23]

Ming,

Thanks for your response. The above error is indeed from WRF in compiled in Debug mode. The error is from vspow from "frame/libmassv.f90", line, 371,

subroutine vspow(z,y,x,n)
real*4 x(*),y(*),z(*)
do 10 j=1,n
z(j)=y(j)**x(j)
10 continue
return
end

and later dyn_em/module_big_step_utilities_em.f90 line 1061:

CALL vspow ( p(its,k,j), temp(its), cpovcv_v(its), itf-its+1 )

The "erroneous arithmetic operation" is obviously arising from temp**cpovcv_v. But I don't understand what needs to be done to fix the error.

 

[Ming Chen]

Please print the values of p(its,k,j), temp(its), cpovcv_v(its), itf-its+1temp and its, k, j in dyn_em/module_big_step_utilities_em.F . I am suspicious that some of them are unreasonable. Once you know which variable at what points goes wrong, you can further track down to the origin of the errors.

Ming Chen