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(RESOLVED) Coordinate system (datum) compatibility between GFS/WPS/WRF/other sources

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H

hconel

Member
Hi,
This is more of a GFS related question, but since the question involves the importing process, I guess this forum is the best place to ask.
AFAIK, systems like Google Earth and USGS Earth Explorer use the WGS-84 coordinate system. I'm using the 0.25deg resolution GFS data as input but I could not find which coordinate system GFS uses.
I'm pretty new to global weather simulations (and details like coordinate systems and projection methods). Does the projection method I choose in WPS (Mercator, Lambert, etc.) affect how the reference lat/long values defined in the namelist.wps end up in the WRF simulation? Are the lat/long values fully compatible between GFS/WPS/WRF and other sources like Google Earth and USGS Earth Explorer?
Thanks,
Hüseyin
 
Hi Hüseyin,
I will try to answer your questions the best I can. The projection you choose in WPS will not change the location/values of lat/lon on your domain or grid. They will simply change the location of map distortion. If you haven't already, take a look at Chapter 3 of the WRF Users Guide for additional information on the available map projections. You may also find the information in this presentation useful (or you may prefer the .pdf version). The lat/lon values should remain constant between external data, WPS, and WRF.

As for the coordinate system for GFS, if you haven't already, you may want to check this page to see if you see what you're looking for. If not, you can probably contact the support group for NCAR's RDA group to ask specifically what you're looking for.
 
Dear kwerner,
Thanks for your reply. This makes everything clearer.
By the way, I've run some pre/postprocessing tests using USGS EarthExplorer data and everything seems to be working in harmony so far.
Regards
 
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