GRIB Requirements

VAPOR has several requirements for reading GRIB data, listed below:

All GRIB files must be decodable by the European Centre for Mid-Range Weather Forecasting (ECMWF) GRIB_API.

The horizontal grid type of the data must be one of the following:

• Regular Latitude-Longitude
• Regular Gaussian Grid
• Polar Stereographic
• Lambert Conformal
• Mercator

The horizontal grid reolutions Ni and Nj must be invarient for all GRIB messages.

The starting and ending horizontal grid coordinates La1, La2, Lo1, Lo2 must be invarient for all GRIB messages.

All 3D variables must have the same vertical resolution (number of levels).

All 3D variables must be on the Isobaric Level (Pa) pressure descriptor accoring to:

• GRIB1, Table 3, Code 100
• GRIB2, Section 3, Table 3.15, Code 100