DD50 method for pressure calculations - WID513

WID513 User Guide
Document code
M211676EN
Revision
G
Language
English
Product
WID513
Document type
User guide

Pressure calculations compatible with the Vaisala DD50 device:

Q F E ⁢ = P o * exp ⁢ ⁡   ( Δ H ⁢   *   G R * ( T + A * Δ H / 2 ) )

Q N H = Q F E * exp ⁡   ( G * H R * ( 288.15 + A * H / 2 ) )

Q F F = Q F E * exp ⁡   ( G * H R * ( T + A * H / 2 + e * C h ) )

Table 1. Variables in DD50 pressure calculations
Variable Explanation
Po Instant barometric pressure of the sensor on the sensor height in hectopascal (hPa)
ΔH Difference in the height (m) between sensor and station height (reference point)
G Acceleration of gravity (m/s2)
R Constant of gas equation for dry air (287 J/kgK)
T Air temperature in kelvin (K). QFE calculation uses constant value 288.15 K
A Lapse rate (0.0065 K/m)
H Station height (for example reference point) in meters (m)
e Water vapor pressure (hPa)
Ch Elevation constant, 0.1074 + (0.0000251 * H)