Code Figure  Meaning  Unit 

019 
Reserved  
20 
Temperature 
K 
2199 
Reserved  
100 
Pressure 
Pa 
101 
Pressure deviation from mean sea
level 
Pa 
102 
Altitude above mean sea level 
m 
103 
Height above ground (see note 1) 
m 
104 
Sigma coordinate 

105 
Hybrid coordinate 

106 
Depth below land surface 
m 
107 
Potential temperature (theta) 
K 
108 
Pressure deviation from ground
to level 
Pa 
109 
Potential vorticity 
K m^{2} kg^{1}
s^{1} 
110 
Geometric height 
m 
111 
Eta coordinate (see note 2) 

112 
Geopotential height 
gpm 
113 
Logarithmic hybrid coordinate 

114159  Reserved  
160 
Depth below sea level 
m 
161191 
Reserved  
192254 
Reserved for Local Use 

255 
Missing 
Notes: 1. Negative values associate to this coordinate will indicate depth below ground surface. If values are all below the surface, use of entry 10^{6} is recommended with positive coordinate values instead. 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. 