How to interpret WRF variables

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Revision as of 21:55, 7 August 2010 by Jmandel (talk | contribs) (→‎Grid)
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Grid

Wrfgrid.png

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 as 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 the point names.

Elevation

Temperature

Wind

Fire variables

Footnotes

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See also

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