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grid = F160- full (or regular) Gaussian grid with 160 latitude lines between the pole and equatorgrid = N320- ECMWF original reduced Gaussian grid with 320 latitude lines between the pole and equator, see Reduced Gaussian Grids for grid numbers used at ECMWFgrid = O640- ECMWF octahedral (reduced) Gaussian grid with 640 latitude lines between the pole and equator
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