Evaluation of the atmospheric density scale height

Much of the current interest in scaling re-entry observables requires consideration of altitude, velocity, and atmospheric density. A derived quantity closely related to these variables is density scale height Hρ, a quantity which is not tabulated in the U.S. Standard Atmosphere, 1962, although an equation relating density scale height to tabulated values of pressure scale height Hρ is given in the text of the document. Computed values of Hρ are only piece-wise continuous if the standard atmosphere is defined with discontinuities in temperature gradient. Between any two consecutive altitude levels having constant temperature gradient between, the standard-atmosphere values of Hρ represent a nearly linear function of altitude, with variations of gravity field strength producing the nonlinearity.