Re: [ferret_users] Calculating relative vorticity

[Ryo Furue <furue@xxxxxxxxxx>]

Hi Billy,

Thanks for your highest praise!

| Amazingly, I think Ryo is wrong about the sphere/cosine business. If  
| (u,v) is given on a lat/lon grid, then Ferret will do this  
| automatically.

But, I don't think Ferret distinguishes vectors from scalars
when it takes derivatives.  Derivatives of vectors are different
from those of scalars.  Look at my formula again:

    d(u cos(phi))/dy

u[y=@DDC] would give you du/dy, which isn't what we want, right?
Or would Ferret somehow figure out that u is an x-component of
a vector and multiply the cosine factor before taking
the derivative?

Cheers,
Ryo