WRF | WRF uses Pnetcdf

Issue

To Be Tested.

Remark

1. Parallel Netcdf4 I/O support (as opposed to pnetcdf) > Unfortunately the WRF model is not capable of using parallel I/O. If you are using netCDF-4, you must install it without activating parallel I/O based on HDF5. It is possible to use compression with netcdf-4 and HDF5 (without parallel I/O). See this page for details: https://www2.mmm.ucar.edu/wrf/users/building_netcdf4.html

2. WRF Build with Parallel NetCDF Support

• export PNETCDF=/projects/WRF/parallel-netcdf/xxx/ (BASH)
• Configure namelist to use pNetCDF

In the namelist.input, the following settings support pNetCDF by setting value to 11:

io_form_boundary

io_form_history

io_form_auxinput2

io_form_auxhist2

Note that you need set nocolons = .true. in the section &time_control of namelist.input

• With pNetCDF support:

  • Timing for Writing wrfout_d03_2010-02-06_01_00_00 for domain 3: 77.62950 elapsed seconds. Timing for Writing wrfout_d03_2010-02-06_02_00_00 for domain 3: 75.74540 elapsed seconds. Timing for Writing wrfout_d03_2010-02-06_03_00_00 for domain 3: 80.26440 elapsed seconds.
• Without pNetCDF support:
  • Timing for Writing wrfout_d03_2010-02-06_01:00:00 for domain 3: 315.81271 elapsed seconds. Timing for Writing wrfout_d03_2010-02-06_02:00:00 for domain 3: 299.80011 elapsed seconds. Timing for Writing wrfout_d03_2010-02-06_03:00:00 for domain 3: 307.18109 elapsed seconds.