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:[email protected]] On Behalf Of Jonathan Gregory Sent: 11 April 2018 18:37 To: [email protected] 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." <[email protected]> ----- > Date: Tue, 10 Apr 2018 13:14:16 +0000 > From: "Snaith, Helen M." <[email protected]> > To: "Saulter, Andrew" <[email protected]> > CC: "[email protected]" <[email protected]> > 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 > <[email protected]<mailto:[email protected]>> > 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 > [email protected]<mailto:[email protected] > > 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 > [email protected]<mailto:[email protected]> > 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 > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
