Surface pressure often refers to the atmospheric pressure at a location on Earth's surface. It is directly proportional to the mass of air over that location.
For numerical reasons, atmospheric models such as general circulation models (GCMs) usually predict the nondimensional logarithm of surface pressure.
The average value of surface pressure on Earth is 985hPa. This is in contrast to mean sea-level pressure, which involves the extrapolation of pressure to sea-level for locations above or below sea-level. The average mean sea-level pressure is 1013.25hPa, or 1 atmosphere (Atm).
Pressure (P), mass (m), and the acceleration due to gravity (g), are related by P = F/A = (m*g)/A, where A is surface area. Atmospheric pressure is thus proportional to the weight per unit area of the atmospheric mass above that location.
Surface Pressure - Area Isotherms
Famous quotes containing the words surface and/or pressure:
“There’s something tragic in the fate of almost every person—it’s just that the tragic is often concealed from a person by the banal surface of life.... A woman will complain of indigestion and not even know that what she means is that her whole life has been shattered.”
—Ivan Sergeevich Turgenev (1818–1883)
“Today’s pressures on middle-class children to grow up fast begin in early childhood. Chief among them is the pressure for early intellectual attainment, deriving from a changed perception of precocity. Several decades ago precocity was looked upon with great suspicion. The child prodigy, it was thought, turned out to be a neurotic adult; thus the phrase “early ripe, early rot!””
—David Elkind (20th century)