Geobaric gradient

Geobaric gradient: a pressure variation at the increasing or decreasing of the level. Its variation is set at 27 feet (8.23 m) for every hPa (or millibar) of pressure difference in standard air. If the air is more or less thick when compared to the standard “sample” (the one that at the sea level has a 1,013.25 hPa pressure and a 15° C temperature), it also varies and this must be taken into consideration to know exactly the real altitude in.

back to the gemological glossary