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your location. Click on “Estimate Elevation” and observe the result. For
an example we will use a console location at 42 ft. above sea level.
3. This tool will provide the ground level elevation at your location, so
you will need to add the right amount for how high above ground level
your console is. If you are on a ground floor and have the console on a
desk, you’ll have to add something like 3
-4 ft. If you are using a GPS
system that tells you elevation, make sure it is right next to the console
and you’ll be able to read the correct elevation right from the GPS
results without further adjustment.
4. With the correct altitude/elevation in hand you will need to determine
the correct offset. To be added to the absolute pressure reading in order
to compute relative pressure (sea level equivalent). Correction tables
can be found on-line in many places. One example is the table found at
the web site at
https://novalynx.com/manuals/bp-elevation-correction-tables.pdf
Locate your elevation in the first column and read the correction in the
third column. This table, however is rather coarse, making it hard to be
precise. An alternative is an on-line calculator such as the one found
here:
http://www.csgnetwork.com/barcorrecthcalc.html
For our example of 42 ft. above sea level we input 42 ft. of elevation
and a standard pressure of 1013.25 hPa/mb and press calculate. We
find
an “absolute barometer value” that should be
-1.5626061222588443 hPa lower than at sea level. The inverse
(because relative pressure is higher than absolute pressure) of this
number will be our “REL PRESS
OFFSET” value. Use the settings
procedure to input +1.6 (nearest rounded value we can input).
Remember
we assume “ABS PRESS
OFFSET” to be 0, so check and
change that as well if necessary.
5. Now we need a reliable reference for pressure at sea level. Locate
the
official identifier for the nearest airport. Refer to “
World Airport
