Jonathon, Helen,
Thanks for the feedback.
I'd looked at the existing 'sea_surface_height' terms but had the same worry as Jonathon that the use of 'amplitude' restricted these to some (unspecified) time integral. What I'm after is definitely a variable that varies as a function of time. It's also unusual in the coastal forecasting community to want to split the various contributions to tide up.
The 'due_to_air_pressure_and_wind' term captures the primary meteorological processes that induce surge. However, these do not capture the effect of tide-surge interaction in shallower waters (for example the extra surge elevation enhances the speed at which the tide propagates so a 'surge residual' can include the propagation speed delta as well as the background super-elevation) nor other secondary variability that we often see in surge residuals, such as steric changes of the water column. So I feel that using a catchall term 'storm_surge', although less specific would have a lot less potential to mislead a user. The option exists, I assume, in the comments attribute for a variable to be more precise about its derivation/generating processes.
So overall, I couldn't find a goldilocks term for either surge or tide that would fit my users understanding of the variables - hence the new suggestions.
Have a good weekend
Andy
-----Original Message-----
From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Jonathan Gregory
Sent: 11 April 2018 18:37
To: cf-metadata at cgd.ucar.edu
Subject: [CF-metadata] proposed new standard name for storm surge residual
Dear Helen and Andy
I noticed the sea_surface_height_amplitude_due_to_X_tide names as well, and I wondered, what does "amplitude" mean here? The definitions of these names don't say, and I feel that we should be clear. I guessed it might mean the amplitude of SSH due to the tidal cycle, whereas I think Andy means the actual tidal height as a function of time. Are you able to clarify?
It's a good point about due_to_air_pressure[_and_wind], thanks. That may not obviously mean "storm surge", which maybe could be inserted in the definition.
Best wishes
Jonathan
----- Forwarded message from "Snaith, Helen M." <h.snaith at bodc.ac.uk> -----
> Date: Tue, 10 Apr 2018 13:14:16 +0000
> From: "Snaith, Helen M." <h.snaith at bodc.ac.uk>
> To: "Saulter, Andrew" <andrew.saulter at metoffice.gov.uk>
> CC: "cf-metadata at cgd.ucar.edu" <cf-metadata at cgd.ucar.edu>
> Subject: Re: [CF-metadata] proposed new standard name for storm surge
> residual
> x-mailer: Apple Mail (2.3445.6.18)
>
> Hi Andy
>
> Many of the sea_surface_height terms have been used in satellite altimetry for some time.
> The tidal components have been split out into
> sea_surface_height_amplitude_due_to_equilibrium_ocean_tide<javascript:
> void(0)>
> sea_surface_height_amplitude_due_to_geocentric_ocean_tide<javascript:v
> oid(0)>
> sea_surface_height_amplitude_due_to_non_equilibrium_ocean_tide<javascr
> ipt:void(0)>
>
> And the pole tide
> sea_surface_height_amplitude_due_to_pole_tide<javascript:void(0)>
>
> In these terms, amplitude has been used to identify the ?above mean
> level? and sea_surface_height is as alias of
> sea_surface_heigth_above_mean_sea_level
>
>
> Also included are the terms
> sea_surface_height_correction_due_to_air_pressure_and_wind_at_high_fre
> quency<javascript:void(0)>
> sea_surface_height_correction_due_to_air_pressure_at_low_frequency<jav
> ascript:void(0)>
>
> The former of which is related to surge I think - it is normally determined from a tidal model and is the response of sea level to changes in air pressure and wind.
>
> Even if these are not the correct terms, as you are not determining a 'correction? but a value - they should be related to the surge components, so do they give the ?due to? component you need?
>
> Helen
>
>
> On 4 Apr 2018, at 17:13, Saulter, Andrew <andrew.saulter at metoffice.gov.uk<mailto:andrew.saulter at metoffice.gov.uk>> wrote:
>
> Dear all,
>
> First posting to this list, so please forgive me if I?m doing it
> wrong?
>
> I?d like to request an addition to the standard name list to include storm surge residual and tide. These variables are generated for the purpose of coastal flood prediction and will be available in future, netCDF based, operational products from the Met Office.
>
> Proposed standard name:
> sea_surface_height_above_mean_sea_level_due_to_storm_surge
> Units: m
> "Sea surface height" is a time-varying quantity. "Height_above_X" means the vertical distance above the named surface X. "Mean sea level" means the time mean of sea surface elevation at a given location over an arbitrary period sufficient to eliminate the tidal signals. The specification of a physical process by the phrase ?due_to_process? means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. Storm surge effects, due to meteorological forcing of the ocean and interaction between the generated surge and tides, are a significant contributor to the observed sea surface height.
>
> Proposed standard name:
> sea_surface_height_above_mean_sea_level_due_to_tide
> Units: m
> "Sea surface height" is a time-varying quantity. "Height_above_X" means the vertical distance above the named surface X. "Mean sea level" means the time mean of sea surface elevation at a given location over an arbitrary period sufficient to eliminate the tidal signals. The specification of a physical process by the phrase ?due_to_process? means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. Tides are a significant contributor to the observed sea surface height; here ?tide? denotes a generic variable describing the time varying tidal signal, for example as generated based on a summation of harmonically analysed components, or resulting from the application of such components as boundary conditions to a numerical tidal model.
>
> Many thanks
> Andy
>
>
> Andy Saulter
> Surge, Waves and Metocean Projects Manager Met Office FitzRoy Road
> Exeter Devon EX1 3PB
> Tel: +44 (0)1392 884703 Fax: +44 (0)1392 885681
> andrew.saulter at metoffice.gov.uk<mailto:andrew.saulter at metoffice.gov.uk
> > http://www.metoffice.gov.uk<http://www.metoffice.gov.uk/>
>
>
> --
> This message has been scanned for viruses and dangerous content by
> MailScanner<http://www.mailscanner.info/>, and is believed to be
> clean. _______________________________________________
> CF-metadata mailing list
> CF-metadata at cgd.ucar.edu<mailto:CF-metadata at cgd.ucar.edu>
> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>
> ________________________________
> This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system.
> ________________________________
> _______________________________________________
> CF-metadata mailing list
> CF-metadata at cgd.ucar.edu
> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
----- End forwarded message -----
_______________________________________________
CF-metadata mailing list
CF-metadata at cgd.ucar.edu
http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Received on Fri Apr 20 2018 - 10:04:18 BST
