Levels 3: Fixed levels or layers for which the data are included
Code tables
| Id | Octet 10 | Octet 11 | Octet 12 |
| 00 | Reserved | ||
| 01 | Ground or water surface | ||
| 02 | Cloud base level | ||
| 03 | Level of cloud tops | ||
| 04 | Level of 0°C isotherm | ||
| 05 | Level of adiabatic condensation lifted from the surface | ||
| 06 | Maximum wind level | ||
| 07 | Tropopause | ||
| 08 | Nominal top of atmosphere | ||
| 09 | Sea bottom | ||
| 10-19 | Reserved | ||
| 100 | Isobaric surface | Pressure in hPa (2 octets) | |
| 101 | Layer between two isobaric surfaces | Pressure of top in kPa | Pressure of bottom in kPa |
| 102 | Mean sea level | ||
| 103 | Specified altitude above mean sea level | Altitude in metres (2 octets) | |
| 104 | Layer between two specified altitudes | Altitude of top in hm | Altitude of bottom in hm above mean sea level |
| 105 | Specified height level above ground | Height in metres (2 octets) | |
| 106 | Layer between two specified height levels | Height of top in hm | Height of bottom in hm above ground |
| 107 | Sigma level | Sigma value in 1/10 000 (2 octets) | |
| 108 | Layer between two sigma levels | Sigma value of top in 1/100 | Sigma value of bottom in 1/100 |
| 109 | Hybrid level | Level number (2 octets) | |
| 110 | Layer between two hybrid levels | Level number of top | Level number of bottom |
| 111 | Depth below land surface | Depth in centimetres (2 octets) | |
| 112 | Layer between two depths below land | Depth of upper surface in cm | Depth of lower surface surface in cm |
| 113 | Isentropic (theta) level | Potential temperature in K (2 octets) | |
| 114 | Layer between two isentropic levels | 475 K minus theta of top in K | 475 K minus theta of bottom in K |
| 115 | Level at specified pressure difference | Pressure difference in hPa (2 octets) from ground to level | |
| 116 | Layer between two levels at specified pressure differences from ground to level | Pressure difference from ground to top level in hPa | Pressure difference from ground to bottom level in hPa |
| 117 | Potential vorticity surface | 109 K m2 kg1 s1 | |
| 118 | Reserved | ||
| 119 | ETA* level | ETA value in 1/10000 (2 octets) | |
| 120 | Layer between two ETA* levels | ETA value at top of layer in 1/100 | ETA value at bottom of layer in 1/100 |
| 121 | Layer between two isobaric surfaces (high precision) | 1100 hPa minus pressure of top in hPa | 1100 hPa minus pressure of bottom in hPa |
| 122-124 | Reserved | ||
| 125 | Specified height level above ground (high precision) | Height in centimetres (2 octets) | |
| 126 | Reserved | ||
| 127 | Satellite Spectral band (as defined by INPE/CPTEC and used by ECMWF) | (2 octets) | |
| 128 | Layer between two sigma levels (high precision) | 1.1 minus sigma of top, in 1/1000 of sigma | 1.1 minus sigma of bottom, in 1/1000 of sigma |
| 129-140 | Reserved | ||
| 141 | Layer between two isobaric surfaces (mixed precision) | Pressure of top in kPa | 1100 hPa minus pressure of bottom in hPa |
| 142-159 | Reserved | ||
| 160 | Depth below sea level | Depth in metres (2 octets) | |
| 161-199 | Reserved | ||
| 20 | Isothermal level | Temperature in 1/100 K | |
| 200 | Entire atmosphere (considered as a single layer) | ||
| 201 | Entire ocean (considered as a single layer) | ||
| 202-209 | Reserved | ||
| 21-99 | Reserved | ||
| 210 | Isobaric surface (high precision) (ECMWF extension) | Pressure in Pa (2 octets) | |
| 211-254 | Reserved |
( 1) For reserved values, or if not defined, octets 11 and 12 shall contain zero.
( 2) The ETA vertical coordinate system involves normalizing the pressure at some point on a specific level by the mean sea level pressure at that point.