Vaisala PTB330 - Manual (Page 135)

Appendix A ______________________________________________________ Calculation Formulas
VAISALA ______________________________________________________________________ 133
APPENDIX A
CALCULATION FORMULAS
This appendix contains the calculation formulas used by the product.
Height compensated pressure values (QFE, QNH, and HCP) are
calculated using the following equations:
where:
p = measured air pressure [hPa]
h
QFE
= height difference between the barometer and reference
level [m]
g = 9.81 [m/s2]
R = 287 [J/kg/K]
T = temperature [K]
where:
H
QNH
= station elevation [m]
g = 9.81 [m/s
2
]
R = 287 [J/kg/K]
T = 288.15 [K]
= -0.0065 [K/m]