Sailing Glossary - Term Standard atmosphere

A standard unit of atmospheric pressure, defined as the pressure exerted by a 760 mm column of mercury at standard gravity (980.665 cm/sec²) at 0°C. 1 standard atmosphere is equal to 760 mm Hg, 29.9212 inches Hg, or 1013.250 mb. Also, a hypothetical vertical distribution of atmospheric temperature, pressure, and density which, by international agreement, is taken to be representative of the atmosphere.