[Wrf-users] WRF Domain Wizard - global domains

[Eric Altshuler]

Hello,

I am trying to set up a global WRF-ARW domain with a nest using the WRF Domain Wizard (version 1.22). Unfortunately, it doesn't seem to be working correctly.

After I choose the map projection to be 'Lat-Lon Global WRF3', the grid dimensions default to 100 x 50 with a resolution of 400.8 km. I want higher resolution, but if I change it to 100 km (for example), the domain wizard does not automatically increase the grid dimensions to ensure a global domain. Likewise, if I increase the grid dimensions to 400 x 200, it does not adjust the resolution to compensate, resulting in a domain that is larger than the entire globe. Regardless of the resolution I choose, the namelist.input file displayed in the next step (namelist.input editor) has dx = dy = 156343.322 for the coarse domain (and dx = dy = 20000 for the nest) and time_step = 600. In addition, if I set up a nest with a parent grid ratio of 3, the namelist.input file still has parent_grid_ratio = 5 for all nests. Finally, many other parameters in namelist.input (e.g., damping and PD advection options) are different from those in the namelist.input which is generated when I choose a regional domain. The latter namelist is very similar to the default namelist.input that's included with the WRFV3 source code (WRFV3/test/em_real/namelist.input), but for a global domain the namelist is very different, which doesn't make sense.

A more general question is: Given the grid dimensions (e_we and e_sn) for a global domain, how are dx and dy calculated for the global domain and any nests? Are dx and dy given in degrees or meters, and is it necessary to specify them in namelist.wps and namelist.input?

Thanks for your attention.

Best regards,

Eric L. Altshuler
Assistant Research Scientist
Center for Ocean-Land-Atmosphere Studies
4041 Powder Mill Road, Suite 302
Calverton, MD 20705-3106
USA

E-mail: ela at cola.iges.org
Phone: (301) 902-1257
Fax: (301) 595-9793