Subaru 2001 Impreza Owner's Manual page 164

B Barometer
HS6004CB
The display indicates atmospheric pressure in the passenger
compartment.
Range: 21.26 to 30.86 inHg or 720 to 1045 hpa
NOTE
D The reading may change during air-conditioner operation,
door window operation, driving in a tunnel, and so forth.
D All barometric readings reported in local weather reports are
corrected to a sea-level reading regardless of altitude. The Gauge
Pack displays true local air pressure and hence may differ signifi-
cantly from local weather reports (especially at higher altitudes).
The barometer is not adjustable.
D Since air pressure changes with altitude, the barometric read-
ing will vary when the vehicle is moving up or down an incline.
For accurate barometric trending, the vehicle should be station-
ary.
B Altimeter
The altimeter has two modes, Standard elevation mode and Relative
elevation mode.
6-20