Section 0: Indicator section
| Octets | Key | Type | Content |
| 1-4 | identifier | ascii | GRIB (coded according to the CCITT International Alphabet No. 5) |
| 5-7 | totalLength | unsigned | Total length of GRIB message (including Section 0) |
| 8 | editionNumber | unsigned | GRIB edition number (currently 1) |