28
6.4.2 Rate of Change of Pressure Graph
The rate of change of pressure graphic is shown to the left of the barometric
pressure and signifies the difference between the daily average pressure and
the 30 day average (in hPa).
Figure 17
6.4.3 Viewing Pressure History
Press the [PRESSURE -] button to view the 12 hour, 24 hour, 48 hour and
72 hour pressure average.
6.4.4 Relative Pressure Calibration Discussion
To compare pressure conditions from one location to another,
meteorologists correct pressure to sea-level conditions. Because the air
pressure decreases as you rise in altitude, the sea-level corrected pressure
(the pressure your location would be at if located at sea-level) is generally
higher than your measured pressure.
Thus, your absolute pressure may read 28.62 inHg (969 mb) at an altitude of
1000 feet (305 m), but the relative pressure is 30.00 inHg (1016 mb).
The standard sea-level pressure is 29.92 inHg (1013 mb). This is the average
sea-level pressure around the world. Relative pressure measurements
greater than 29.92 inHg (1013 mb) are considered high pressure and relative
pressure measurements less than 29.92 inHg are considered low pressure.
Summary of Contents for WS2910
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