[ncl-talk] Map Reprojection, Spatial Aggregation and Regridding

[Scott Capps]

I have created a NetCDF file with data (terrain slope) on the WGS84 4326
map projection (ncdump -h output shown below):

dimensions:
lon = 27382 ;
lat = 25569 ;
variables:
char crs ;
crs:grid_mapping_name = "latitude_longitude" ;
crs:long_name = "CRS definition" ;
crs:longitude_of_prime_meridian = 0. ;
crs:semi_major_axis = 6378137. ;
crs:inverse_flattening = 298.257223563 ;
crs:spatial_ref = "GEOGCS[\"WGS 84\",DATUM[\"WGS_1984\",SPHEROID[\"WGS
84\",6378137,298.257223563,AUTHORITY[\"EPSG\",\"7030\"]],AUTHORITY[\"EPSG\",\"6326\"]],PRIMEM[\"Greenwich\",0],UNIT[\"degree\",0.0174532925199433],AUTHORITY[\"EPSG\",\"4326\"]]"
;
crs:GeoTransform = "-121.3651264724438 0.0002790528478797247 0
39.07036311976184 0 -0.0002790528478797247 " ;
double lat(lat) ;
lat:standard_name = "latitude" ;
lat:long_name = "latitude" ;
lat:units = "degrees_north" ;
double lon(lon) ;
lon:standard_name = "longitude" ;
lon:long_name = "longitude" ;
lon:units = "degrees_east" ;
float Band1(lat, lon) ;
Band1:long_name = "GDAL Band Number 1" ;
Band1:_FillValue = -9999.f ;
Band1:grid_mapping = "crs" ;

// global attributes:
:GDAL_AREA_OR_POINT = "Area" ;
:Conventions = "CF-1.5" ;
:GDAL = "GDAL 2.3.2, released 2018/09/21" ;
:history = "Wed Dec 05 11:41:45 2018: GDAL CreateCopy(
territory_epsg4326_slope.nc, ... )" ;
}

And, I would like to calculate the average terrain slope in each grid cell
on my coarser WRF domain (2km resolution).

Can NCL correctly handle the re-projection from the file above:

Geodetic CRS: WGS84
Datum: World Geodetic System 1984
Ellipsoid: WGS 84
Prime Meridian: Greenwich

to my WRF Lambert Conformal Conic projection while calculating the average
terrain slope in each overlapping, coarser resolution WRF gridcell?

Any help or suggestions are appreciated.

Thank you,

Scott
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