Hi all, Thanks for your feedback Roy. Here are the definitions we suggest for the 7 new parameters. They are the usual definitions in the observations world.
- *sea_surface_wave_significant_height* The already existing definition is "Height is the vertical distance above the surface." We believe that this definition defines the "sea_surface_wave_height" part, but not the "significant" part. Could it be possible to revise it to make it more precise? We think that a more precise definition could be :"Height is the vertical distance above the surface. The significant height is defined as the average height of the highest third of observed sea surface waves over a 30 minutes period." - *sea_surface_wave_maximum_height ** *Height is the vertical distance above the surface. The maximum height is defined as the height of the highest sea surface wave observed over a 30 minutes period. * *- *sea_surface_wave_average_height * Height is the vertical distance above the surface. The average height is defined as the average height of the sea surface waves observed over a 30 minutes period. - *sea_surface_wave_height_of_highest_tenth* Height is the vertical distance above the surface. The height of the highest tenth is defined as the average height of the highest tenth of observed sea surface waves over a 30 minutes period. - *sea_surface_wave_height_of_the_highest_crest* The crest is the vertical distance above the mean sea surface to the maximum in a wave. Height of the highest crest is the maximum value of wave crests observed over a 30 minutes period. - *sea_surface_wave_deepest_trough* Trough is the vertical distance below the mean sea surface to the minimum in a wave. The deepest trough is the maximum value of wave troughs observed over a 30 minutes period. - *sea_surface_primary_swell_wave_significant_height* definition of "sea_surface_wave_significant_height" + The primary swell wave is the most energetic swell wave. - *sea_surface_secondary_swell_significant_height* definition of "sea_surface_wave_significant_height" + The secondary swell wave is the second most energetic swell wave. Regards, Elodie On 03/05/2016 11:00, Lowry, Roy K. wrote: > > Dear Elodie, > > > Many thanks. I totally agree with your revised proposal for seven new > Standard Names. I also congratulate you for the clarity of your proposals. > > > The next stage would be for you to provide revised definitions for > these seven. I will also do my best to provide my comments to you for > your energy, steepness and period proposals by the end of the week. > > > 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:* 03 May 2016 08:56 > *To:* [email protected] > *Cc:* [email protected] > *Subject:* Re: [CF-metadata] Waves > > 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/MZbqvYs5QwJvpeaetUwhCQ==> >> to report this email as spam. >> > > ------------------------------------------------------------------------ > This message (and any attachments) is for the recipient only. 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