[Wrf-users] WPS Geographical Data:

[Kevin Matthew Nuss]

Hi,

The short answer is "No. you do not need to change the index file. And you
SHOULD NOT change the index files."

The index file that you had in you email describes the geographical data
that comes with WRF, the data in the geog.tar.gz. It describes that data as
it currently is, NOT how it will be used in you model run. The WPS programs
will convert from that data's geographical format to the grid you describe
in your namelist.wps file. Because of the conversions within WPS, the
format and projection of that geographical data is independent of the
projection used for your model run.

If you change the index files, WPS will MIS-understand that data and use it
wrongly, giving you bad results.

You do not need to worry about index files unless you provide
*replacement*data for one or more of those geographical files provided
with WRF. (Some
people use higher resolution terrain data, or improved landuse data, etc. )
In that case, you have to provide the index file with the replacement data
so the WPS programs can understand that replacement data and convert it
(and interpolate it) for use in your model runs.

Hope that explanation helps a little,
Kevin


On Tue, Jan 29, 2013 at 5:31 AM, MORRIS KENOBI ISIMA <kenobimorris at yahoo.com
> wrote:

> Dear WRF users,
> Does one need to edit the index file of WPS geographical data to reflect
> your domain and location before using it? And if it does happen that you
> didn't edit before using to run your case, will the results generated be
> accurate?
>
> index file for Albedo:
>
> type=continuous
> projection=regular_ll
> dx=0.144
> dy=0.144
> known_x=1.0
> known_y=1.0
> known_lat=-89.928
> known_lon=-179.928
> wordsize=1
> missing_value=0.
> tile_x=1250
> tile_y=1250
> tile_z_start=1
> tile_z_end=12
> tile_bdr=3
> units="percent"
> description="Monthly surface albedo"
>
> I am running a case with Lambert as map projection. So, do I need to
> replace it?
>
> Any suggestions will be greatly appreciated,
>
> Thanks,
>
> K I Isima
>
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>
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