known_lat , known_lon and resolution of static input data

Dataset specific topics involving WPS.

known_lat , known_lon and resolution of static input data

Postby centurion555 » Fri May 26, 2017 10:29 am

Dear all,

I'm using WRFV3.9. I have successfully completed test run using 1 Arc-Second Global SRTM dataset located at:

https://lta.cr.usgs.gov/SRTM1Arc

I had no problems writing this data to geogrid format. But I have two questions:

1) What are exactly known_lat, known_lon in index file ? As far as I understand they are the coordinates of the lower left grid box of the input raster data. But are they coordinates of the corner or center of the lower left grid box ? If I see index file from the global 30s landuse data "landuse_30s_with_lakes" :

projection=regular_ll
dx=0.00833333
dy=0.00833333
known_x=1.0
known_y=1.0
known_lat=-89.99583
known_lon=-179.99583

it looks like they are coordinate of the center of the first grid box (lower left) grid box. Please clarify.

2) I have nested domain 3.0 km => 1.0 km => 333.33 m => 111.11 m and I want to use the above mentioned SRTM-1Arc and 100m CORINE Landuse (mapped to 24 USGS categories) for these four Domains . But WRF tutorial "namelist.wps: Best Practices" recommends to choose a resolution of input data that is slightly better than the grid resolution for the domain. As I have only one resolution of input data I want to use, what is best way to proceed? Should I upscale to create coarser resolution input datasets or use different interpolation methods for different domains .
centurion555
 
Posts: 2
Joined: Fri May 26, 2017 9:46 am

Re: known_lat , known_lon and resolution of static input dat

Postby centurion555 » Thu Jul 27, 2017 5:31 am

Still no reply ?
centurion555
 
Posts: 2
Joined: Fri May 26, 2017 9:46 am


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