Hello Roy and all, I think you are right Roy, let's look at height variables first to keep things manageable. I'm sorry it took me a little while to reply, I wanted to first discuss things with Marta and wave modellers from Copernicus.
We agree that the estimator should be included in a long_name, not in the Standard Name. So the list of names we "need" for height are reduced to: - sea_surface_wave_significant_height -> already exists - *sea_surface_wave_maximum_height ** * - *sea_surface_wave_average_height * We think that for the maximum_wave_height and mean_wave_height, the statistics should be included in the Standard Name and not in the cell_methods, because it is really part of the definition and not something applied afterwards to the physical parameter. Am I making sense? - *sea_surface_wave_height_of_highest_tenth* - *sea_surface_wave_height_of_the_highest_crest* - *sea_surface_wave_deepest_trough* - *sea_surface_primary_swell_wave_significant_height* - *sea_surface_secondary_swell_wave_significant_height* - sea_surface_wind_wave_significant_height -> already exists So we would be down to 7 new Standard Names. Regards, Elodie On 02/05/2016 10:51, Lowry, Roy K. wrote: > > > Dear Elodie, > > > Following my comments on Hs, here are some comments on the rest of > your proposals for additional wave height Standard Names. Most of the > comments follow the same theme of placing statistic derivation methods > out of the Standard Name. My proposed changes will affect your > definitions, but let's discuss names first to keep things manageable. > > > *sea_surface_wave_zero_upcrossing_average_height_of_highest_tenth* > > Use sea_surface_wave_average_height_of_highest_tenth as the Standard > Name with the derivation method in the long name. If zero-upcrossing > analysis is based on the method specified by Tucker and Draper then > include ‘Tucker-Draper’ in the label.** > > *sea_surface_wave_zero_upcrossing_average_height* > > Suggest sea_surface_wave_average_height This raises the question of > whether ‘average’ should be handled by a cell method? However, there > is a precedent for the inclusion of statistics in the name already > established for waves e.g. > sea_surface_wave_zero_upcrossing_average_height.** > > *sea_surface_wave_maximum_height* > > OK > > *sea_surface_wave_zero_upcrossing_maximum_height* > > Use sea_surface_wave_maximum_height and Long Name for the derivation > method. > > *sea_surface_wave_crest_through_maximum_height* > > Should ‘through’ be ‘trough’? Also, I’m not clear on exactly what this > is. Is it the distance from the deepest trough to the highest crest in > the analysis (i.e. the sum of sea_surface_wave_deepest_trough and > sea_surface_wave_height_of_the_highest_crest) or the greatest crest to > following trough distance in the analysis. Could you clarify then I’ll > suggest a change to the name? > > *sea_surface_wave_deepest_through* > > Assume you mean sea_surface_wave_deepest_trough, in which > case OK. > > *sea_surface_wave_height_of_the_highest_crest* > > OK > > *sea_surface_primary_swell_wave_significant_height* > > ‘Spectral’ removed from your suggestion with derivation > moved to Long Name. > > *sea_surface_secondary_swell_wave_significant_height* > > ‘Spectral’ removed from your suggestion with derivation > moved to Long Name. > > Your other height proposal > (sea_surface_wind_wave_spectral_significant_height) is covered by the > pre-existing Standard Name sea_surface_wind_wave_significant_height. > > > Cheers, Roy. > > > Please note that I partially retired on 01/11/2015. I am now only > working 7.5 hours a week and can only guarantee e-mail response on > Wednesdays, my day in the office. All vocabulary queries should be > sent to [email protected]. Please also use this e-mail if your > requirement is urgent. > > > > ------------------------------------------------------------------------ > *From:* CF-metadata <[email protected]> on behalf of > Elodie Fernandez <[email protected]> > *Sent:* 28 April 2016 16:18 > *To:* [email protected] > *Cc:* [email protected] > *Subject:* [CF-metadata] Waves > > Hi all, > > So here are our proposals for wave variables that will be available > through the European Copernicus Marine service. It's split in two > "categories": names for the whole spectrum and names for the > partitions. I added in copy for this topic Marta de Alfonso > Alonso-Munoyerro who is an expert in waves from Puertos del Estado. > > ------------------------------------- > Whole partition > ------------------------------------- > > 1. Height > > Significant height can be measured using different methods, so we > think that the already existing definition should be more precise and > that new names should be added. > > 1.a *"sea_surface_significant_height"* (modification of definition) > unit m > Height is the vertical distance above the surface. Significant wave > height can be estimated by zero upcrossing analysis and by spectral > analysis. The generic significant wave height is used when the > estimator is unknown. > > 1.b *"sea_surface_wave_spectral_significant_height"* > unit m > Height is the vertical distance above the surface. It can be defined > from spectral analysis. The wave directional spectrum can be written > as a five dimensional function S(t,x,y,f,theta) where t is time, x and > y are horizontal coordinates (such as longitude and latitude), f is > frequency and theta is direction. S has the standard name > sea_surface_wave_directional_variance_spectral_density. S can be > integrated over direction to give S1= integral(S dtheta) and this > quantity has the standard name > sea_surface_wave_variance_spectral_density. Frequency moments, M(n) of > S1 can then be calculated as follows: M(n) = integral(S1 f^n df), > where f^n is f to the power of n. Spectral significant wave height is > defined as 4* sqrt (M(0)) = 4 * sqrt ( integral(S1 df) ) > > 1.c *"sea_surface_wave_zero_upcrossing_significant_height"* > unit m > Height is the vertical distance above the surface. The significant > wave height is defined from zero upcrossing analysis as the average > height of the highest one third waves. > > 1.d. *"sea_surface_wave_zero_upcrossing_average_height_of_highest_tenth*" > unit m > Height is the vertical distance above the surface. The average height > of highest tenth waves is defined from zero upcrossing analysis as the > average height of the highest one tenth waves. > > 1.e *"sea_surface_wave_zero_upcrossing_average_height"* > unit m > Height is the vertical distance above the surface. The average height > is defined from zero upcrossing analysis as the average of wave heights. > > 1.f *"sea_surface_wave_maximum_height"* > unit m > Height is the vertical distance above the surface. Estimated maximum > wave height is not measured but estimated from others parameters like > significant wave height. > > 1.h *"sea_surface_wave_zero_upcrossing_maximum_height"* > unit m > Height is the vertical distance above the surface. Maximum zero > crossing wave height is the measured maximum height of the waves > separated by zero upcrossing analysis. > > 1.i *"**sea_surface_wave_crest_through_maximum_height"* > unit m > Height is the vertical distance above the surface. Maximum crest > trough wave height is the measured maximum height of the waves > separated by crests method. > > 1.j *"sea_surface_wave_deepest_through*" > unit m > Trough is the vertical distance below 0 to the minimum in a wave. > Depth of the deepest trough is the maximum value of wave troughs. > > 1.k *"sea_surface_wave_height_of_the_highest_crest"* > unit m > Crest is the vertical distance above 0 to the maximum in a wave. > Height of the highest crest is the maximum value of wave crests. > > 2. Energy > > 2.a *"sea_wave_spectrum_peak_energy"* > unit mms (meter*meter*second) > The wave directional spectrum can be written as a five dimensional > function S(t,x,y,f,theta) where t is time, x and y are horizontal > coordinates (such as longitude and latitude), f is frequency and theta > is direction. S has the standard name > sea_surface_wave_directional_variance_spectral_density. S can be > integrated over direction to give S1= integral(S dtheta) and this > quantity has the standard name > sea_surface_wave_variance_spectral_density. Wave spectrum peak energy > is the maximum value of the variance spectral density (max(S1)). > > 3. Period > > 3.a *"sea_surface_wave_mean_period"* > unit s > A period is an interval of time, or the time-period of an > oscillation. Mean or averaged wave period is the average value of the > wave periods and can be estimated by zero upcrossing analysis and by > spectral analysis. The generic average wave period is used when the > estimator is unknown. > > 3.b *"sea_surface_wave_zero_upcrossing_significant_wave_period"* > unit s > A period is an interval of time, or the time-period of an oscillation. > The significant wave period is defined from zero upcrossing analysis > as the average period of the highest one third waves. > > 3.c *"sea_surface_wave_zero_upcrossing_average_one_tenth_wave_period"* > unit s > A period is an interval of time, or the time-period of an oscillation. > The average period highest one tenth waves is defined from zero > upcrossing analysis as the average period of the highest one tenth waves. > > 3.d*"sea_surface_wave_maximum_period"* > unit s > A period is an interval of time, or the time-period of an oscillation. > The maximum wave period is defined from zero upcrossing analysis as > the maximum period of the waves. > > 3.e*"sea_surface_wave_period_of_highest_wave"* > unit s > A period is an interval of time, or the time-period of an oscillation. > The period of the highest wave is defined from zero upcrossing > analysis as the period of the highest wave. > > 4. Direction > > 4.a *"sea_surface_wave_from_mean_direction"* > unit degree > from_direction is used in the construction X_from_direction and > indicates the direction from which the velocity vector of X is coming. > The mean wave direction is the average direction from which waves are > coming. > > 4.b *"sea_surface_wave_from_direction_at_spectral_peak"* > unit degree > from_direction" is used in the construction X_from_direction and > indicates the direction from which the velocity vector of X is coming. > The spectral peak is the most energetic wave in the total wave > spectrum. The wave direction at spectral peak is the direction from > which waves are coming at the spectral peak. > > 5. Steepness > > 5.a *"sea_surface_wave_maximum_steepness"* > unit dimensionless > The wave steepness is defined as the ratio of the wave height divided > by the wavelength. The maximum wave steepness is the maximum value. > > ------------------------------------- > Partitions > ------------------------------------- > > We also wish to add names for the three "main" variables defining > waves for three partitions: the wind wave, the primary swell wave and > the secondary swell wave. These three variables are > - the spectral significant height (1.b of our proposal > sea_surface_wave_spectral_significant_height) > - the direction (4.b of our proposal > sea_surface_wave_from_direction_at_spectral_peak) > - the period (already existing name > sea_surface_wave_mean_period_from_variance_spectral_density_first_frequency_moment) > > So we propose for all three to replace in the name "sea_surface_wave" > with "sea_surface_wind_wave", "sea_surface_primary_swell_wave" and > "sea_surface_secondary_swell_wave". And we believe the definitions > should be the definitions already existing or proposed on this email, > with the addition at the end of the definition of the partition > itself: "The directional wave spectrum can be separated into several > partitions: wind wave contribution (WW), primary swell (SW1) > contribution (the most energetic swell) and secondary swell > contribution (SW2).", with a bit more detail for the wind wave: "Wind > waves are waves on the ocean surface generated by the local wind." > > For example: > *sea_surface_secondary_swell_wave_from_direction * > unit degree > The directional wave spectrum can be separated into several > partitions: wind wave contribution (WW), primary swell (SW1) > contribution (the most energetic swell) and secondary swell > contribution (SW2). The mean wave direction is the average direction > from which waves are coming for the secondary swell wave partition. > > Regards, > Elodie Fernandez > > ------------------------------------------------------------------------ > 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. > ------------------------------------------------------------------------ > > > Click here > <https://www.mailcontrol.com/sr/aTuQ7uMKgJzGX2PQPOmvUoXR17WSa92vOq9PA2GkX%21wqc9r2+aHkABxsAjMYwoaOGQ0bqizKrCEYNBM7q0TQEQ==> > to report this email as spam. >
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