Hi Jonathan,
Sorry for my late reply. In discussions within the science group behind
our application, they suggest the following names:
northward_northward_derivative_of_gravity_potential (Txx)
westward_westward_derivative_of_gravity_potential (Tyy)
upward_upward_derivative_of_gravity_potential (Tzz)
northward_upward_derivative_of_gravity_potential (Txz)
northward_westward_derivative_of_gravity_potential (Txy)
westward_upward_derivative_of_gravity_potential (Tyz)
Yes they are spatial derivatives of the potential in the specified
directions, ending up with unit s-2;
Let me know if this can be accepted by the group.
Regards,
On vr, 2015-01-23 at 16:52 +0000, Jonathan Gregory wrote:
> 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 -----
> _______________________________________________
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> CF-metadata at cgd.ucar.edu
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--
--
N.E. Cornejo, Msc.
Engineering, Space & Science
http://www.stcorp.nl
s[&]t
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