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Conversion of absolute atmospheric pressure
to sea level pressure.

Precision measurements of atmosferic pressure using Wiring / Arduino
with BMP85/180/280 and BME280 sensors.

OTA
1. The BOSCH formula assumes a standard temperature of 15 degrees Celsius.
This formula is good when placing a barometer in the interior:

p0 = p / pow(1.0 - h / 44330.0, 5.255);


2. Babinet's formula. The formula is very accurate for altitudes less than 500m:

p0 = - p * (h + 16000.0 + 64.0 * t) / (h - 16000.0 - 64.0 * t);


3. Modified ICAO formula. Probably the most versatile formula:

p0 = p / pow(1.0 - 0.0065 *h / (t + 273.15), 5.255);

p0[Pa]pressure at sea level
p[Pa]absolute pressure obtained by measurement
t[C]air temperature in degrees Celsius
h[m]altitude of the measuring station


Feb / 2018

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