Correcting pressure to sea level

The weather service, most airports, radio stations, and television stations adjust the atmospheric pressure to a common reference (sea level). Eq. 1 can be used to find the difference in pressure between the sea level and the site in kPa. That value (dP) is then added to the absolute pressure measurement returned by the ClimaVue 50 G2 as seen in the example program. Once that is done, the program shows the pressure conversion to hPa. U. S. Standard Atmosphere and dry air were assumed when Eq. 1 was derived (Wallace, J. M. and P. V. Hobbes, 1977: Atmospheric Science: An Introductory Survey, Academic Press, pp. 59-61).

Eq. 1

The value dP is in kPa and the site elevation, E, is in meters. Add dP value to the offset in the measurement instruction.

Use Eq. 2 to convert feet to meters.

Eq. 2

The corrections involved can be significant. For example, at 100 kPa and 20 °C, barometric pressure will decrease by 0.11 kPa for every 10 m increase in altitude.