CatEye Q3A - Manual (Page 63)

ENG-62
Relation between the altitude and atmospheric pressure
The higher the altitude, the lower the atmospheric pressure. At an altitude of 500 m
or less, the pressure changes by 12 hPa per 100 m of altitude.
Knowledge related to weather and altitude
The change in atmospheric pressure when the weather changes from a good condition such
as clear and sunny, to a bad condition such as rainy and cloudy is equivalent to the ascending
altitude of about 100 m. Thunder storms will be result in even larger changes. Furthermore,
the atmospheric pressure measurements may change more than 30 m in altitude change from
sunrise to sunset even under stable clear weather conditions.
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