Scale Height

Description

In various scientific contexts, a scale height is a distance over which a quantity decreases by a factor of e (approximately 2.71828, the base of natural logarithms). It is usually denoted by the capital letter H.

Scale height used in a simple atmospheric pressure model

For planetary atmospheres, scale height is the increase in altitude for which the atmospheric pressure decreases by a factor of e. The scale height remains constant for a particular temperature. It can be calculated by the formula shown here.

Planetary examples

Approximate scale heights for selected Solar System bodies follow.

Venus: 15.9 km
Earth: 8.5 km
Mars: 11.1 km
Jupiter: 27 km
Saturn: 59.5 km
Titan: 40 km
Uranus: 27.7 km
Neptune: 19.1–20.3 km

Related formulas

Variables

Hscale height (m)
Rspecific gas constant (J*kg-1*K-1)
Tmean atmospheric temperature in kelvins (250 K for Earth) (K)
gacceleration due to gravity on planetary surface (m/s2)