>I am trying to read JMA forecast files in GRIB format with NCL.
>The number of longitudinal grids reduced toward the poles
>thus grids are not rectilinear.
>These files do not follow NCL's convection and
>does not provide gridx and gridy.
>Longitude grid arrays are problematic as below.
>Is there anything I can do in the script?
>Otherwise I will preprocess the files with other tools.
The new version of NCL [a028] will handle these GRIB
"quasi-regular" grids (ie: reduced grids). It autonatically
unpacks the grid into 1.25 x 1.25 degree grids.
The "lat_37" and "lon_37" variables will look like:
Total Size: 292 bytes
Number of Dimensions: 1
Dimensions and sizes: [lon_37 | 73]
Number Of Attributes: 8
GridType : Cylindrical Equidistant Projection Grid (Quasi-Regular)
units : degrees_east
Dj : 1.25
Di : 1.25
Lo2 : 60
La2 : 90
Lo1 : -30
La1 : 0
---- ncl 5> printVarSummary (lat_37)
Variable: lat_37 Type: float Total Size: 292 bytes 73 values Number of Dimensions: 1 Dimensions and sizes: [lat_37 | 73] Coordinates: lat_37: [ 0..90] Number Of Attributes: 8 GridType : Cylindrical Equidistant Projection Grid (Quasi-Regular) units : degrees_north Dj : 1.25 Di : 1.25 Lo2 : 60 La2 : 90 Lo1 : -30 La1 : 0 ----
Fot those interested, more information on these resuced grids is available at: http://www.nco.ncep.noaa.gov/pmb/docs/on388/tableb.html#WAFS
If you are interested in helping us to beta test these new capabilities, please send email to Mary Haley [ haley AT ucar.edu ] and let her know what kind of system you have. She will send you more information about these new capabilities and a binary to try.
Regards Dennis Shea
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