Abstract
The geostrophic coordinate transformation is a contact transformation that preserves the correspondence between the slopes of geopotential surfaces ϕ in physical space and the slopes of the surfaces ϕ, the maps of ϕ, in transformed space. The transformation back to physical space may be accomplished by integration along characteristic surfaces. This technique may be used to determine the time and place where a discontinuity would form as a function of the initial conditions. A model solution is used to illustrate properties of the transformation.
