Dear Napoleon
Thanks for your email. I'm sorry, I don't understand these, because some of
them have two directions, some only one, yet all have the same unit s-2.
If P is the geopotential (J kg-1 = m2 s-2), the acceleration due to gravity
g=dP/dz (m s-2). This could have eastward, northward and upward derivatives
dg/dx=d2P/dxdz, dg/dy=d2P/dydz, dg/dz=d2P/dz2. By northward upward derivative,
for instance, do you mean d2g/dydz=d3P/dydz2? Or perhaps by Tij you mean
d2P/dx_i dx_j in my notation? In that case the northward upward derivative
is d2P/dydz=dg/dy, which is the northward derivative of the acceleration due
to gravity. Txz Tyz Tzz are then the three derivatives of g, and Txx Tyy Txy
are Iward_Jward_derivative_of_geopotential. To be consistent we could name
all six of them in this second form, as second derivatives of geopotential.
Best wishes
Jonathan
----- Forwarded message from Napoleon Cornejo <cornejo at stcorp.nl> -----
> Date: Tue, 20 Jan 2015 17:23:20 +0100
> From: Napoleon Cornejo <cornejo at stcorp.nl>
> To: Jonathan Gregory <j.m.gregory at reading.ac.uk>
> CC: cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] Standard Names for: Ocean Kinetic Energy and
> Relative Vorticity
>
> Hi Jonathan,
>
> Since these quantities will be calculated in Local North Oriented Frame
> (LNOF), I would like to submit these names for the gradients:
>
> northward_derivative_of_acceleration_due_to_gravity (Txx)
> westward_derivative_of_acceleration_due_to_gravity (Tyy)
> upward_derivative_of_acceleration_due_to_gravity (Tzz)
> northward_upward_derivative_of_acceleration_due_to_gravity (Txz)
> northward_westward_derivative_of_acceleration_due_to_gravity (Txy)
> westward_upward_derivative_of_acceleration_due_to_gravity (Tyz)
>
> Let me know if these seem appropriate. All with unit: s-2.
>
> Regards,
>
> On Wed, 2014-12-17 at 13:34 +0000, Jonathan Gregory wrote:
>
> > Dear Napoleon
> >
> > > Is it the convention to include the direction in the name? We will be
> > > calculating the gradient in more then one axis (Txy, Txz, etc, for a
> > > total of 6 quantities).
> >
> > Yes, it is the convention. There are not many tensor quantities named but it
> > is not unpredented e.g. downward_eastward_momentum_flux_in_air. As you see,
> > both sign and direction are indicated.
> >
> > Best wishes
> >
> > Jonathan
> > _______________________________________________
> > CF-metadata mailing list
> > CF-metadata at cgd.ucar.edu
> > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>
>
> --
> N.E. Cornejo, Msc.
> Engineering, Space & Science
> http://www.stcorp.nl
> s[&]t
>
>
----- End forwarded message -----
Received on Fri Jan 23 2015 - 09:52:01 GMT
