Difference between revisions of "How to interpret WRF variables"
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==Grid== | ==Grid== | ||
| − | + | [[File:Wrfgrid.png|250px]] | |
| + | |||
| + | Grids in WRF are logically rectilinear. Variables for WRF cell indexed '''(i,j,k)''' can be located at one of 4 possible point. You can tell where by looking at the WRF registry or the attributes of [[NetCDF]] files, which WRF uses as I/O format. You can also tell by the fact that staggered variables have the staggered dimension larger by one, since there needs to be variable at the last boundary face. | ||
| + | * at the center of the cell - theta points, not staggered | ||
| + | * at the center of the left face - U point, staggered in X | ||
| + | * at the center of the front face - V point, staggered in Y | ||
| + | * at the center of the bottom face - W point, staggered in Z | ||
| + | Scalar variables (such thermodynamical variables, hence the theta: temperature, pressure,...) generally live at theta-points. One exception is the geopotential, which lives at W-points. Components of the wind velocity vector U,V,W live at the corresponding points, hence their names. | ||
==Elevation== | ==Elevation== | ||
Revision as of 21:54, 7 August 2010
Grid
Grids in WRF are logically rectilinear. Variables for WRF cell indexed (i,j,k) can be located at one of 4 possible point. You can tell where by looking at the WRF registry or the attributes of NetCDF files, which WRF uses as I/O format. You can also tell by the fact that staggered variables have the staggered dimension larger by one, since there needs to be variable at the last boundary face.
- at the center of the cell - theta points, not staggered
- at the center of the left face - U point, staggered in X
- at the center of the front face - V point, staggered in Y
- at the center of the bottom face - W point, staggered in Z
Scalar variables (such thermodynamical variables, hence the theta: temperature, pressure,...) generally live at theta-points. One exception is the geopotential, which lives at W-points. Components of the wind velocity vector U,V,W live at the corresponding points, hence their names.
Elevation
Temperature
Wind
Fire variables
Footnotes
</references>
See also
- WRF output fields from the WRF-ARW user's guide
- A Description of the Advanced Research WRF Version 3 (June 2008) Fig 7.3 page 59
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