good way to get familiar with WRF code

[order999]

Can someone share the experience on how to get started with the WRF?

 

[Ming Chen]

I would suggest to read the WRF technical notes first. Here is the link to the document:

WRF Technical Note

After you get to know the dynamics, physics and grid structure of WRF, you can proceed to learn how to use it. Below is the User Guide:

WRF Users' Guide

You can download the source codes at:

WRF Modeling System Download

 

[order999]

That sounds like a reasonable approach. Thank you,

 

[order999]

I am running wrf with different number of MPI processes. The resulting model has slightly different statistics. what function could cause numeric instability?

Regards,

 

[order999]

compile wrf 4.2.2 fail with double precision after (configure -r8)

The first fail is (please help) -

module_ra_goddard.f90
module_ra_goddard.f90:1781:128:

1781 | flx_out=flx, flxd_out=flxd,flxu_out=flxu, flxd_surf = flxd_surf, lmask=lmask, irestrict=min(CHUNK,ite-ii+1) )
| 1
Error: Type mismatch in argument ‘fcld’ at (1); passed REAL(4) to REAL(8)
module_ra_goddard.f90:1973:98:

1973 | flx_out=flx, acflxd_out=flxd, acflxu_out=flxu, irestrict=min(CHUNK,ite-ii+1) )
| 1
Error: Type mismatch in argument ‘tb’ at (1); passed REAL(4) to REAL(8)
Command exited with non-zero status 1
0.15user 0.03system 0:00.18elapsed 100%CPU (0avgtext+0avgdata 51476maxresident)k
0inputs+8outputs (0major+9815minor)pagefaults 0swaps
../configure.wrf:344: recipe for target 'module_ra_goddard.o' failed

 

[Ming Chen]

Note that WRF outputs could be slightly different if you compile the code with different compilers and/or run with different number of processors. Such difference is acceptable. Please don't worry for it.

 

[order999]

Is there any discussion in the user document on how much difference is expected? Thanks,

 

[Ming Chen]

There is no quantitative metrics to describe how large the difference could be. It depends on many factors (number of processors, integration period, physics and dynamic options, etc.)

 

[order999]

Thank you,