Sorry, I think there's a confusing point about item 4. The term wave in your definition has many definitions, including in physical oceanography (see
http://en.wikipedia.org/wiki/Wave_(disambiguation) for a longer list). Can we clarify its use refers not to an oceanographic wave, but (presumably) to a wave function representing the rate of sea level change? (Or does it actually relate to ocean waves? In which case I don't understand what it has to do with sea level change.)
John
On Jul 16, 2012, at 03:01, Lauret Olivier wrote:
>
> Dear Jonathan,
>
> I think following the previous exchanges
>
> 1. tendency_of_global_average_sea_level_change (m/year)
> Global average sea level change is due to change in volume of the water in the ocean, caused by mass and/or density change, or to change in the volume of the ocean basins, caused by tectonics etc. It is sometimes called "eustatic", which is a term that also has other definitions. It differs from the change in the global average sea surface height relative to the centre of the Earth by the global average vertical movement of the ocean floor. Zero sea level change is an arbitrary level. "tendency_of_X" means derivative of X with respect to time.
>
> 2. tendency_of_sea_surface_height_above_sea_level (m/year)
> ?Sea_level means mean sea level, which is close to the geoid in sea areas. "Sea surface height" is a time-varying quantity. "tendency_of_X" means derivative of X with respect to time.?
>
>
> 3. global_average_sea_level_change_amplitude (m)
> ?Global average sea level change is due to change in volume of the water in the ocean, caused by mass and/or density change, or to change in the volume of the ocean basins, caused by tectonics etc. It is sometimes called "eustatic", which is a term that also has other definitions. It differs from the change in the global average sea surface height relative to the centre of the Earth by the global average vertical movement of the ocean floor. Zero sea level change is an arbitrary level. Amplitude is the magnitude of a wave modeled by a sinusoidal function.?
>
>
> 4. global_average_sea_level_change_phase (degree)
> ?Global average sea level change is due to change in volume of the water in the ocean, caused by mass and/or density change, or to change in the volume of the ocean basins, caused by tectonics etc. It is sometimes called "eustatic", which is a term that also has other definitions. It differs from the change in the global average sea surface height relative to the centre of the Earth by the global average vertical movement of the ocean floor. Zero sea level change is an arbitrary level. Phase is the initial angle of a wave modeled by a sinusoidal function.?
>
> ..could be added as new standard names.
>
> There is still one problem to be solved, it?s about how to mention that it is for example annual, or semi-annual, or 60 days amplitude and phase of the signal. You suggested to precise it into coordinates variables and introduce a standard name such as ?harmonic_period?. Shall we use seconds units for that quantity, which are canonical units?
> For the definition, CF already provides ?A period is an interval of time, or the time-period of an oscillation.?.
>
> Thanks!
>
> Olivier
>
>
> -----Message d'origine-----
> De : CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] De la part de Jonathan Gregory
> Envoy? : jeudi 12 juillet 2012 15:57
> ? : cf-metadata at cgd.ucar.edu
> Objet : Re: [CF-metadata] Standard names for sea level change
>
> Dear Olivier
>
> > Yes, 'tendency_of_sea_surface_height_above_sea_level' is fine for me. I confirm the "sea_level" part of the standard name is a time mean sea level.
>
> Very good. Is this now the only new standard name you are proposing?
>
> Cheers
>
> Jonathan
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----------------
John Graybeal <mailto:jgraybeal at ucsd.edu> phone: 858-534-2162
Product Manager
Ocean Observatories Initiative Cyberinfrastructure Project:
http://ci.oceanobservatories.org
Marine Metadata Interoperability Project:
http://marinemetadata.org
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