4. Regridding

Users that wish to interpolate their unipost output to a different grid may do so with the wgrib2 utility. The general format for re-gridding to a lat-lon grid is given in the example.

4.1. Examples of wgrib2

Wgrib2 is a versatile program that has the ability to convert grib2 files from one grid to another for various user-defined grids as well as pre-defined NCEP grids. Complete documentation with examples of re-gridding for all available grid definitions can be found at:

http://www.cpc.ncep.noaa.gov/products/wesley/wgrib2/new_grid.html.

Sample command line usage for calling wgrib2:

wgrib2 -new_grid_winds W -new_grid A B C outfile

Where,

W = earth or grid

earth: winds oriented to the earths north and south directions

grid: winds are rotated so that north is relative to the grid

A, B, and C represent the output grid description

Sample lat-lon grid description:

A = latlon

B = lon0:nlon:dlon

lon0 is longitude of first grid point in degrees

nlon is number of longitudes

dlon is grid resolution in degrees of longitude

C = lat0:nlat:dlat

lat0 is latitude of first grid point

nlat is number of latitudes

dlat is grid resolution in degrees of latitude

Note: wgrib2 is not distributed within the UFS weather application. Users may download and install from http://www.cpc.ncep.noaa.gov/products/wesley/wgrib2/.