Rapid Refresh (RAP) and High-Resolution Rapid Refresh (HRRR) Forum

geo_em differences

Posted By: Kyle Hilburn
Date: 11-January-17 2053Z

When I use the GEOGRID.TBL and namelist.wps on your webpage to generate a geo_em file using WRF WPS geogrid, I find differences from the geo_em file provided on your page for SLOPECAT and SNOALB fields in coastal locations for both ocean coastlines and inland lakes. It appears that I am incorrectly interpolating zero values over water onto land. Also, SLOPECAT and SNOALB in the geo_em file on your webpage have non-zero values over small islands that do not appear in my geo_em file for these two fields. For other fields, such as LANDMASK, these small islands do appear in my geo_em file. The namelist.wps specifies the geog_data_res to be modis_lakes+30s. In the GEOGRID.TBL this results in using the modis_landuse_21class_30s static dataset with nearest_neighbor interpolation using values 17 and 21 for water. The GEOGRID.TBL specifies that SLOPECAT is created from the islope data using nearest_neighbor+average_16pt+search for interpolation. The GEOGRID.TBL specifies that SNOALB is created from the maxsnowalb data using four_pt+average_4pt+average_16pt+search for interpolation. Have any of these datasets or interpolation options changed? Is there something tricky that needs to be done to make the interpolation behave properly in coastal locations for these two fields?

Messages In This Thread

geo_em differences -- Kyle Hilburn -- 11-January-17 2053Z

Re: geo_em differences -- Curtis Alexander -- 20-January-17 1643Z

Re: geo_em differences -- Kyle Hilburn -- 20-January-17 1803Z

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