The P-vector is defined by the following equations:
where the partial derivatives were calculated with the use of the cdiff function in GrADS.

Note that the Coriolis parameter used here is defined as f=2*Omega*sin(latitude) and the winds used in the calculation are the observed zonal and meridional winds and are not geostrophic.

The vectors were made by plotting the vector sum of P1 and P2 and colored by the magnitude of the resulting vector.

Units: m s-3