Dear All,
Please find the third part of the wave Standard Name proposal. This includes changes to the definition for five of the six existing wave direction Standard names plus five new Standard names.
Based on the proposal of Elodie and Marta with further off-list discussion by Chris Barker, nan Galbraith and myself.
Cheers, Roy.
Changes to Existing Standard Name Definitions
1) sea_surface_swell_wave_from_direction
Current Definition
Swell waves are waves on the ocean surface. "from_direction" is used in the construction X_from_direction and indicates the direction from which the velocity vector of X is coming.
New Definition
"From_direction" is used in the construction X_from_direction and indicates the direction from which the velocity vector of X is coming. The direction is a bearing in the usual geographical sense, measured positive clockwise from due north. Swell waves are the low frequency portion of a bimodal wave frequency distribution.
2) sea_surface_swell_wave_to_direction
Current Definition
Swell waves are waves on the ocean surface. "to_direction" is used in the construction X_to_direction and indicates the direction towards which the velocity vector of X is headed. The direction is a bearing in the usual geographical sense, measured positive clockwise from due north.
New Definition
"To_direction" is used in the construction X_to_direction and indicates the direction towards which the velocity vector of X is headed. The direction is a bearing in the usual geographical sense, measured positive clockwise from due north. Swell waves are the low frequency portion of a bimodal wave frequency distribution.
3) sea_surface_wave_from_direction
Current Definition
'from_direction' is used in the construction X_from_direction and indicates the direction from which the velocity vector of X is coming.
New Definition
"From_direction" is used in the construction X_from_direction and indicates the direction from which the velocity vector of X is coming. The direction is a bearing in the usual geographical sense, measured positive clockwise from due north.
4) sea_surface_wave_to_direction
Current Definition - No Change Proposed
"to_direction" is used in the construction X_to_direction and indicates the direction towards which the velocity vector of X is headed. The direction is a bearing in the usual geographical sense, measured positive clockwise from due north.
5) sea_surface_wind_wave_from_direction
Current Definition
Wind waves are waves on the ocean surface. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name "upward_air_velocity".) "from_direction" is used in the construction X_from_direction and indicates the direction from which the velocity vector of X is coming.
New Definition
"From_direction" is used in the construction X_from_direction and indicates the direction from which the velocity vector of X is coming. The direction is a bearing in the usual geographical sense, measured positive clockwise from due north. Wind waves are the high frequency portion of a bimodal wave frequency distribution.
6) sea_surface_wind_wave_to_direction
Current Definition
Wind waves are waves on the ocean surface. Wind is defined as a two-dimensional (horizontal) air velocity vector, with no vertical component. (Vertical motion in the atmosphere has the standard name "upward_air_velocity".) "to_direction" is used in the construction X_to_direction and indicates the direction towards which the velocity vector of X is headed. The direction is a bearing in the usual geographical sense, measured positive clockwise from due north.
New Definition
"To_direction" is used in the construction X_to_direction and indicates the direction towards which the velocity vector of X is headed. The direction is a bearing in the usual geographical sense, measured positive clockwise from due north. Wind waves are the high frequency portion of a bimodal wave frequency distribution.
New Standard Names
1) sea_surface_wave_from_direction_at_spectral_peak
The direction from which the waves at the spectral peak are coming. The spectral peak comprises the most energetic waves encountered during the measurement period. The direction is a bearing in the usual geographical sense, measured positive clockwise from due north.
Canonical units = degrees.
2) sea_surface_primary_swell_wave_from_direction
"From_direction" is used in the construction X_from_direction and indicates the direction from which the velocity vector of X is coming. The direction is a bearing in the usual geographical sense, measured positive clockwise from due north. The primary swell wave is the most energetic wave in the low frequency portion of a bimodal wave frequency distribution.
Canonical units = degrees.
3) sea_surface_secondary_swell_wave_from_direction
"From_direction" is used in the construction X_from_direction and indicates the direction from which the velocity vector of X is coming. The direction is a bearing in the usual geographical sense, measured positive clockwise from due north. The secondary swell wave is the second most energetic wave in the low frequency portion of a bimodal wave frequency distribution.
Canonical units = degrees.
4) sea_surface_wave_maximum_steepness
Wave steepness is defined as the ratio of the wave height divided by the wavelength. The maximum wave steepness is the greatest value observed during the observation period. Wave height is defined as the vertical distance from a wave trough to the following wave crest. The wavelength is the horizontal distance from this trough to the next trough.
Canonical units = dimensionless.
5) sea_wave_spectrum_peak_energy
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)).
Canonical units = Square metre seconds (m^2.s)
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 enquiries at bodc.ac.uk<mailto:enquiries at bodc.ac.uk>. Please also use this e-mail if your requirement is urgent.
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Received on Wed Jun 01 2016 - 07:06:34 BST
