Hi Jonathan,

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).

Kind regards,

On Tue, 2014-12-16 at 17:52 +0000, Jonathan Gregory wrote:

> Dear Napoleon
> 
> Ah, I see. It is dg/dz. In that case I would call it
> 
> upward_derivative_of_acceleration_due_to_gravity
> 
> since Xward_derivative is a construction we use in other names. With this
> name it would be a negative number (g decreases as you go upward). If you
> want a positive number it would be downward_derivative_etc. It is good
> to specify the direction of the derivative, because you might want to name
> other ones. You might later want a name for dg/dx, for example.
> 
> Best wishes
> 
> Jonathan
> 
> > > > Gravity Potential Gradient
> > > > standard name:  gravity_potential_gradient
> > > > unit: s-2
> > > 
> > > There is an existing stdname of specific_gravitational_potential_energy
> > > in J kg-1 = m2 s-2. Since taking a gradient has a sign and direction, your
> > > quantity could be called
> > >   upward_derivative_of_specific_gravitational_potential_energy
> > > for consistency with other names for derivatives, and it's in m s-2, 
> > > isn't it?
> > > - not s-2. However this quantity could also, more familiarly, be called 
> > > the
> > > acceleration_due_to_gravity i.e. g. Is it g you mean? I suppose g is the
> > > vertical derivative of geopotential, which isn't quite the same as GPE. 
> > > Are
> > > you making a distinction here?
> > > 
> > 
> > With this quantity I have make a correction and say it is rather a second 
> > order
> > derivative of the potential, more related to spatial rate of change of g.  
> > Like what is described here:
> > http://www.gradiometry.com/gradiometry  In some cases, the unit used is the 
> > eotvos, but we prefer s-2.
> > Perhaps just gravity_gradient ?


-- 
N.E. Cornejo, Msc.
Engineering, Space & Science
http://www.stcorp.nl
s[&]t


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