My thought exactly.
john
At 6:13 AM +0100 4/1/08, Roy Lowry wrote:
>Hi Nan,
>
>I missed the point that it was a co-ordinate variable. Now I understand I totally agree with wave_frequency.
>
>Cheers, Roy.
>
>>>> Nan Galbraith <ngalbraith at whoi.edu> 3/31/2008 5:08 pm >>>
>
>Thanks, Alison. Wave_frequency would be better, although it
>implies, to me, the frequency of wave peaks where we really
>could use a term for a coordinate parameter of anything that
>can be reported in the frequency domain. So, I'm not sure why
>'frequency' itself isn't sufficient in this case, other than a
>possible conflict with sound frequency ... although its a stretch
>to see how these could be mistaken for one another. A specific,
>non-coordinate parameter like brunt_vaisala_frequency_in_air
>should of course keep its more definitive standard name.
>
> > Don't forget we can have internal waves (waves propagated on subsurface
> > density boundaries like thermoclines) as well as surface waves in water
> > bodies.
>
>Yes, I guess that's my point: why would we need a separate
>frequency coordinate parameter for frequency of internal
>waves? The meaning of the coordinate parameter is the same
>in both cases, and the standard name of the measured parameter
>explains itself.
>
>We don't specify the variable being measured when we use depth
>as a coordinate parameter in CF, so I'm not sure why this case
>should be different.
>
> > My working hypothesis is that optimum combination of detail and
> > generality is medium + property
>
>Mine is that it's a bad idea to provide information that might be
>misleading or conflicting in a NetCDF field when that information
>is contained in another field, the standard_name. In this case, the
>parameter's standard name, sea_surface_wave_variance_spectral_density,
>gives information about the quantity being reported, and the name of
>the coordinate parameter should contain exactly enough information
>to make the measured parameter definitively understood. If there is
>another standard name where this would not be the case, I haven't
>come across it. That's the strength of NetCDF, and we may as well
>take advantage of its strong points, since we put up with its weak
>points as well.
>
>Wave_frequency seems like a better alternative and a good compromise,
>to me.
>
>Cheers - Nan
>
>
> > >>> "Pamment, JA (Alison)" <J.A.Pamment at rl.ac.uk> 03/31/08 11:09 AM >>>
> > >
> > > One of our parameters is sea_surface_wave_variance_spectral_density,
> > > with coordinate variables time and frequency.
> > >
> > > Sea_surface_wave_frequency is an accepted standard name, but I
> > > would like to know why 'frequency' is not preferable, being more
> > > generic. As an analogy, we can use 'depth' as the coordinate variable
> > > for temperatures, and are not so specific as to require
> > > sea_water_temperature_depth. Is specifying sea_surface_wave
> > > really necessary, and might it not be misleading if the parameter
> > > is not actually "plain" sea_surface_waves?
>
> > I'm not an expert in this area myself, so I'm not quite sure what you
> > mean by "plain" sea_surface_waves. However, to respond to your general
> > point, I agree that sea_surface_wave_frequency is very specific.
> > The original proposal (see
> > http://www.cgd.ucar.edu/pipermail/cf-metadata/2006/000958.html) was for
> > wave_frequency and it was submitted along with quite a list of other sea
> > surface wave names. I suspect that it was changed for consistency with
> > the other names. I think that we need to at least use the term
> > wave_frequency rather than simply 'frequency' because it is not the
> > only kind of frequency in standard names. We have the names
> > sound_frequency, which could in fact be described by wave_frequency, and
> > brunt_vaisala_frequency_in_air, which is a parameter that relates to the
> > static stability of air and is useful for determining whether gravity
> > waves will be generated, for example, by flow over orography. I think
> > that we could use wave_frequency quite adequately for fluid dynamical
> > waves, sound waves and electromagnetic waves independent of the medium
> > in which they occur. Would you be happy with wave_frequency?
> >
> > Best wishes,
> > Alison
>
>
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----------
John Graybeal <mailto:graybeal at mbari.org> -- 831-775-1956
Monterey Bay Aquarium Research Institute
Marine Metadata Initiative: http://marinemetadata.org || Shore Side Data System: http://www.mbari.org/ssds
Received on Tue Apr 01 2008 - 07:22:32 BST
