Campbell Scientific CS105/CS105MD Barometric Pressure Sensor - Manual (Page 15)

CS105/CS105MD Barometric Pressure Sensor
6. Correcting Pressure to Sea Level
The weather service, most airports, radio stations, and television stations
reduce the atmospheric pressure to a common reference (sea level). Equation 1
can be used to find the difference in pressure between the sea level and the site.
That value (dP) is then added to the offset (600 mb) in the measurement
instruction. U. S. Standard Atmosphere and dry air were assumed when
Equation 1 was derived (Wallace, J. M. and P. V. Hobbes, 1977: Atmospheric
Science: An Introductory Survey, Academic Press, pp. 59-61).
dP
E
= − −
⎛
⎝
⎜
⎞
⎠
⎟
⎧
⎨
⎪
⎩⎪
⎫
⎬
⎪
⎭⎪
1013 25 1 1
44307 69231
5.25328
.
.
(1)
The value dP is in millibars and the site elevation, E, is in meters. Add dP to
the offset in the measurement instruction.
Use Equation (2) to convert from feet to meters.
E m
E ft
ft m
( )
( )
.
=
3 281
(2)
Sea level correction is automatically coded into datalogger programs when
using Short Cut.
7. Maintenance
There are no user-serviceable parts on CS105. Vaisala recommends
recalibrating the CS105 every year. Contact Campbell Scientific, Inc., phone
(435) 753-2342, for an RMA number before returning the sensor for
recalibration.
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