Chapman function

A Chapman function, denoted ch, describes the integration of an atmospheric parameter along a slant path on a spherical Earth, relative to the vertical or zenithal case. It applies to any physical quantity with a concentration decreasing exponentially with increasing altitude. At small angles, the Chapman function is approximately equal to the secant function of the zenith angle, .

The Chapman function is named after Sydney Chapman, who introduced the function in 1931. It has been applied for absorption (esp. optical absorption) and the ionosphere.

This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.