## ON388 - TABLE 3
TYPE AND VALUE OF LEVEL
(PDS Octets 10, 11, & 12)

Revised 07/31/2006
Red text depicts changes made since 02/07/2006

VALUE (Octet 10) | MEANING | CONTENTS (Octets 11 & 12) | ABBREV
--- | --- | --- | ---
0-99 | special codes, See Table 3a | 0 | 0 | -
100 | isobaric level | pressure in hectoPascals (hPa) (2 octets) | ISBL
101 | layer between two isobaric levels | pressure of top (kPa) | pressure of bottom (kPa) | ISBY
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 (hm) | altitude of bottom (hm) | GPMY
105 | specified height level above ground | height in meters (2 octets) | HTGL
106 | layer between two specified height levels above ground | height of top (hm) | height of bottom (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 at top | level number at bottom | HYBY
111 | depth below land surface | centimeters (2 octets) | DBLL
112 | layer between two depths below land surface | depth of upper surface (cm) | depth of lower surface (cm) | DBLY
113 | isentropic (theta) level | Potential Temperature (K) (2 octets) | THEL
114 | layer between two isentropic levels | 475 K minus thEta of top in K | 475 K minus thEta of bottom in K | THEY
115 | level at specified pressure difference from ground to level | Pressure difference in hPa (2 octets) | SPDL
116 | layer between two levels at specified pressure difference from ground to level | pressure difference from ground to top level in hPa | pressure difference from ground to bottom level in hPa | SPDY
117 | potential vorticity(pv) surface | pv value in units of 10-9Km2/kgs (2 octets) | PVL
119 | Eta level | Eta value in 1/10000 (2 octets) | EtaL
120 | layer between two Eta levels | Eta value at top of layer in 1/100 | Eta value at bottom of layer in 1/100 | EtaY
121 | layer between two isobaric surfaces (high precision) | 1100 hPa minus pressure of top, in hPa | 1100 hPa minus pressure of bottom, in hPa | IBYH
125 | specified height level above ground (high precision) | Height in centimeters (2 octets) | HGLH
126 | isobaric level | pressure in Pascals (Pa) (2 octets) | ISBP
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 | 1100hPa minus pressure of bottom, in hPa | IBYM
160 | depth below sea level | Depth in meters (2 octets) | DBSL
200 | entire atmosphere (considered as a single layer) | 0 (2 octets) | EATM
201 | entire ocean (considered as a single layer) | 0 (2 octets) | EOCN

Note: | The numbering allows for additions within this framework:
| 100-119 normal precision 120-139 high precision 140-159 mixed precision

## ON388 - TABLE 3a
SPECIAL LEVELS
(PDS Octet 10)

VALUE | LEVEL | 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 | -
NCEP Special Levels & Layers:
204 | Highest tropospheric freezing level | HTFL
206 | Grid scale cloud bottom level | GCBL
207 | Grid scale cloud top level | GCTL
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
215 | Cloud ceiling | CEIL
220 | Planetary Boundary Layer (derived from Richardson number) | PBLRI
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
235 | Ocean Isotherm Level (1/10 deg C) | OITL
236 | Layer between two depths below ocean surface depth of upper surface (dam) (octet 11) depth of lower surface (dam) (octet 12) | OLYR
237 | Bottom of Ocean Mixed Layer (m) | OBML
238 | Bottom of Ocean Isothermal Layer (m) | OBIL
239 | Layer Ocean Surface and 26C Ocean Isothermal Level | S26CY
240 | Ocean Mixed Layer | OMXL
242 | Convective cloud bottom level | CCBL
243 | Convective cloud top level | CCTL
244 | Convective cloud layer | CCY
245 | Lowest level of the wet bulb zero | LLTW
246 | Maximum equivalent potential temperature level | MTHE
247 | Equilibrium level | EHLT
248 | Shallow convective cloud bottom level | SCBL
249 | Shallow convective cloud top level | SCTL
251 | Deep convective cloud bottom level | DCBL
252 | Deep convective cloud top level | DCTL
253 | Lowest bottom level of supercooled liquid water layer | LBLSW
254 | Highest top level of supercooled liquid water layer | HTLSW

Office Note 388 - GRIB