WRF ARW User's Guide - MMM - UCAR

WPS
However, if the GWDO scheme were employed, the finest resolution of GWDO static
data that is still lower in resolution than the model grid would be the 30-minute data, in
which case the user should specify
geog_data_res = ‘30m+10m’,
If none of ‘2deg’, ‘1deg’, ‘30m’, or ‘20m’ are specified in combination with other
resolutions of static data in the geog_data_res variable, the ‘10m’ GWDO static data
will be used, since it is also designated as the ‘default’ resolution in the GEOGRID.TBL
file. It is worth noting that, if 10-minute resolution GWDO data are to be used, but a
different resolution is desired for other static fields (e.g., topography height), the user
should simply omit ‘10m’ from the value given to the geog_data_res variable, since
specifying
geog_data_res = ‘10m+30s’,
for example, would cause geogrid to use the 10-mintute data in preference to the 30second
data for the non-GWDO fields, such as topography height and land use category,
as well as for the GWDO fields.
Using Multiple Meteorological Data Sources
The metgrid program is capable of interpolating time-invariant fields, and it can also
interpolate from multiple sources of meteorological data. The first of these capabilities
uses the constants_name variable in the &metgrid namelist record. This variable may
be set to a list of filenames – including path information where necessary – of
intermediate-formatted files which contains time-invariant fields, and which should be
used in the output for every time period processed by metgrid. For example, short
simulations may use a constant SST field; this field need only be available at a single
time, and may be used by setting the constants_name variable to the path and filename
of the SST intermediate file. Typical uses of constants_name might look like
&metgrid
constants_name = '/data/ungribbed/constants/SST_FILE:2006-08-16_12'
/
or
&metgrid
constants_name = 'LANDSEA', 'SOILHGT'
/
The second metgrid capability – that of interpolating data from multiple sources – may be
useful in situations where two or more complementary data sets need to be combined to
produce the full input data needed by real.exe. To interpolate from multiple sources of
time-varying, meteorological data, the fg_name variable in the &metgrid namelist record
WRF-ARW V3: User’s Guide 3-22