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calculate the grid file to be used for remapbil

Added by Enrico Gabrielli 6 months ago

I have to reproject the data from Climate Projections RCP4.5 and RCP 8.5 downscaled @2.2 km over Italy (https://dds.cmcc.it/#/dataset/climate-projections-rcp85-downscaled-over-italy) into R for a small area of 4 pixels.

netcdf has these features for the grid:
float lon[rlon,rlat] (Contiguous storage)
_FillValue: NaN
standard_name: longitude
long_name: longitude
_CoordinateAxisType: Lon
units: degrees_east
8 byte int crs_rotated_latitude_longitude[] (Contiguous storage)
grid_north_pole_latitude: 47
grid_north_pole_longitude: -168
grid_mapping_name: rotated_latitude_longitude
float lat[rlon,rlat] (Contiguous storage)
_FillValue: NaN
standard_name: latitude
long_name: latitude
_CoordinateAxisType: Lat
units: degrees_north
rlat Size:2
standard_name: grid_latitude
long_name: rotated latitude
axis: Y
units: degrees
rlon Size:2
standard_name: grid_longitude
long_name: rotated longitude
axis: X
units: degrees
To transform EPSG:4326 back into latlon EPSG:4326 with rmapbil, how should I construct the grid.txt?
Below is that right?
gridtype = lonlat
xsize = 2
ysize = 2
xfirst = -168
xinc = 0.034
yfirst = 47
yinc = 0.020
I'm not sure about xinc and yinc

Thank you


Replies (1)

RE: calculate the grid file to be used for remapbil - Added by Enrico Gabrielli 6 months ago

cdo griddes '/home/bonushenricus/Documenti/lavoro/dati/cosmos/VHR-PRO_IT2km_CMCC-CM_rcp85_CCLM5-0-9_1hr_315704_villa_masini.nc' #
  1. gridID 1 #
    gridtype = curvilinear
    gridsize = 4
    datatype = float
    xsize = 2
    ysize = 2
    xname = lon
    xdimname = rlon
    xlongname = "longitude"
    xunits = "degrees_east"
    yname = lat
    ydimname = rlat
    ylongname = "latitude"
    yunits = "degrees_north"
    xvals = 12.12109 12.14901 12.12113 12.14906
    yvals = 44.25236 44.25233 44.27236 44.27233
    scanningMode = 0
    gridtype = projection
    gridsize = 4
    xsize = 2
    ysize = 2
    xname = rlon
    xlongname = "rotated longitude"
    xunits = "degrees"
    yname = rlat
    ylongname = "rotated latitude"
    yunits = "degrees"
    xfirst = 0.0867550000548363
    xinc = 0.0200000032782555
    yfirst = 1.25242495536804
    yinc = 0.0200001001358032
    scanningMode = 0
    grid_mapping = crs_rotated_latitude_longitude
    grid_mapping_name = rotated_latitude_longitude
    grid_north_pole_latitude = 47.
    grid_north_pole_longitude = -168.

Trying this grid text below again doesn't work

gridtype = lonlat
xsize = 2
ysize = 2
xfirst = 12
xinc = 0.0200000032782555
yfirst = 47
yinc = 0.0200001001358032

because the result has the center at 47 and 12.
But how can I identified the correct corner from the grid caratheristics from original netcdf?

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