Exner function
The Exner function is a parameter used in atmospheric modeling. Depending on the application, the Exner function may be defined as
or as a non-dimensional form
where is a standard reference surface pressure ; is the specific gas constant for dry air; is the specific heat capacity of dry air at constant pressure; is the absolute temperature; and is the potential temperature. The non-dimensional form can be used as a vertical coordinate in some numerical weather prediction applications, resulting in a simpler mathematical formulation compared to using pressure as the vertical coordinate. It is named after Felix Maria von Exner-Ewarten.