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 106 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. 