TABLE 3: VERTICAL LEVELS
| VALUE | DESCRIPTION | REQUIRED PARAMETERS | ABBREV. | |
| 0-99 | Special Codes | (See Table 3a below) | ||
| 100 | Isobaric level | Pressure in hPa (2 octets) | ISBL | |
| 101 | Layer between two isobaric levels | Pressure of top in kPa |
Pressure of bottom in kPa |
|
| 102 | Mean sea level | 0 | 0 | MSL |
| 103 | Specified altitude above MSL | Altitude in meters | GPML | |
| 104 | Layer between two specified altitudes above MSL | Altitude of top in hm |
Altitude of bottom in hm |
GPMY |
| 105 | Specified height level above ground | Height in meters | TGL | |
| 106 | Layer between two specified height levels above ground | Height of top in hm |
Height of bottom in hm |
HTGY |
| 107 | Sigma level | Sigma value in 1/10000 (2 octets) | SIGL | |
| 108 | Layer between two sigma levels | Sigma value at top in 1/100 |
Sigma value at bottom in 1/100 |
SIGY |
| 109 | Hybrid level | Level number (2 octets) | HYBL | |
| 110 | Layer between two hybrid levels | Level number of top | Level number of bottom | HYBY |
| 111 | depth below land surface | Depth in cm (2 octets) | DBLL | |
| 112 | Layer between two depths below land surface |
Depth of upper surface |
Depth of lower surface |
DBLY |
| 113 | Isentropic (theta) level | Potential temperature in K | THEL | |
| 114 | Layer between two isentropic levels |
475 K minus theta of top |
475 K minus theta of bottom in K | THEY |
| 115 | Level at specified pressure difference from ground | Pressure difference in hPa (2 octets) | SPDL | |
| 116 | Layer between two levels at specified pressure difference from ground | Pressure difference from ground to top in hPa | Pressure difference from ground to bottom in hPa | SPDY |
| 117 | Potential vorticity surface | Potential vorticity value in units of 10-6 K m2/kg s | PVL | |
| 119 | ETA level | ETA value in 1/1000 (2 octets) | ETAL | |
| 120 | Layer between two ETA levels | ETA value at top in 1/100 |
ETA value at bottom in 1/100 |
ETAY |
| 121 | Layer between two isobaric surfaces (high precision) | 1100 minus pressure of top in hPa |
1100 minus pressure of bottom in hPa |
IBYH |
| 125 | Specified height level above
ground (high precision) |
Height in cm (2 octets) | HGLH | |
| 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 |
SGYH |
| 141 | Layer between two isobaric surfaces (mixed precision) | Pressure of top in hPa | 1100 minus pressure of bottom in hPa | IBYM |
| 160 | Depth below sea level | Depth in m (2 octets) | DBSL | |
| 200 | Entire atmosphere | 0 (2 octets) | EATM | |
| 201 | Entire ocean | 0 (2 octets) | EOCN | |
| 204-244 | NCEP Special Levels & Layers | See Table 3a | ||
TABLE 3a: SPECIAL VERTICAL LEVELS
| VALUE | DESCRIPTION | ABBREV. |
| 00 | Reserved | |
| 01 | Ground or water surface | SFC |
| 02 | Cloud base level | CBL |
| 03 | Cloud top level | CTL |
| 04 | Level of 0 deg (C) isotherm | 0DEG |
| 05 | Level of adiabatic condensation lifted from the surface | ADCL |
| 06 | Maximum wind level | MWSL |
| 07 | Tropopause | TRO |
| 08 | Nominal top of atmosphere | NTAT |
| 09 | Sea bottom | SEAB |
| 10-19 | Reserved | |
| 20 | Isothermal level (temperature in 1/100 K in octets 11 and 12) | TMPL |
| 21-99 | Reserved | |
| 204 | Highest tropospheric freezing level | HTFL |
| 209 | Boundary layer cloud bottom level | BCBL |
| 210 | Boundary layer cloud top level | BCTL |
| 211 | Boundary layer cloud layer | BCY |
| 212 | Low cloud bottom level | LCBL |
| 213 | Low cloud top level | LCTL |
| 214 | Low cloud layer | LCY |
| 222 | Middle cloud bottom level | MCBL |
| 223 | Middle cloud top level | MCTL |
| 224 | Middle cloud layer | MCY |
| 232 | High cloud bottom level | HCBL |
| 233 | High cloud top level | HCTL |
| 234 | High cloud layer | HCY |
| 242 | Convective cloud bottom level | CCBL |
| 243 | Convective cloud top level | CCTL |
| 244 | Convective cloud layer | CCY |