Re: Geostrophic velocities

[Rob Scott <scottr@xxxxxxxxxxxxxxxxxx>]

On Fri, 15 Jan 1999, Bruno Levier wrote:

> Hi!
> 
> I'm trying to calculate geostrophic velocities using ferret.
> Could you help me?
> 
> Thanks
> 
>   Bruno
> 

Salut Bruno!
I am assuming that you want to calculate the surface geostrophic current
using dynamic topography data. Please forgive me if I have misunderstood
your intention.
Rob

! have dynamic topography in variable ssh, units=[m], grid = grid_ssh
SET GRID grid_ssh
LET omega = 7.292e-5                        ! rotation rate of earth [rad/s]  
LET f = 2*omega*sin(y*3.14159/180)          ! Coriolis in [1/s]
LET g = 9.8                                 ! see back of Gill 1982 for
                                            ! more accurate g = g(y)[m/s^2]
LET/TITLE="u_g" u =  9.8/f*ssh[y=@DDC]*(-1) ! get u_g  [m/s] centred diff.
LET/TITLE="v_g" v =  9.8/f*ssh[x=@DDC]      ! get v_g  [m/s]