ESS227
Prof. Jin-Yi Yu
Advantage of Using P-Coordinate
•Thus in the isobaric coordinate
system the horizontal pressure gradient force is measured by
the gradient of geopotential at constant pressure.
•Density no longer appears
explicitly in the pressure gradient force; this is a distinct
advantage of the isobaric system.
•Thus, a given geopotential
gradient implies the same geostrophic wind at any
height, whereas a given horizontal pressure gradient
implies different values of the geostrophic wind depending on the
density.