Dear Rob et al.,
I have reviewed all the comments submitted in this thread. There is clearly strong support for the addition of this name and the discussion seems to have reached agreement on the following:
sea_surface_wave_directional_spread_at_variance_spectral_density_maximum (Canonical unit: degree)
'The quantity with standard name sea_surface_wave_directional_spread_at_variance_spectral_density_maximum is the directional spread of the most energetic waves. Directional spread is the (one-sided) directional width within a given sub-domain of the wave directional spectrum, 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. For a given mean wave (beam) direction the quantity approximates half the root mean square width about the beam axis, as derived either directly from circular moments or via the Fourier components of the wave directional spectrum.'
The name, units and definition are all consistent with existing names. This name is accepted for publication in the standard name table and will be added in the November update.
Best wishes,
Alison
------
Alison Pamment Tel: +44 1235 778065
NCAS/Centre for Environmental Data Archival Email: alison.pamment at stfc.ac.uk
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.
-----Original Message-----
From: CF-metadata <cf-metadata-bounces at cgd.ucar.edu> On Behalf Of Alison Pamment - UKRI STFC
Sent: 16 October 2018 15:50
To: 'Rob Thomas' <Rob.Thomas at Marine.ie>; Jonathan Gregory <j.m.gregory at reading.ac.uk>
Cc: cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] Spectral wave direction spread parameter
Dear Rob,
Apologies that I haven't responded in this thread until today. I see from a quick scan of the comments that the name is pretty much agreed. I need to check through properly, and if all is in order then the name can be accepted and added in the next update to the table. I'll have a look now.
Best wishes,
Alison
------
Alison Pamment Tel: +44 1235 778065
NCAS/Centre for Environmental Data Archival Email: alison.pamment at stfc.ac.uk
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.
-----Original Message-----
From: CF-metadata <cf-metadata-bounces at cgd.ucar.edu> On Behalf Of Rob Thomas
Sent: 16 October 2018 15:31
To: Jonathan Gregory <j.m.gregory at reading.ac.uk>
Cc: cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] Spectral wave direction spread parameter
Hi Jonathon,
Do you need any more details to progress this addition? I'm happy with Roy's updated definition.
Cheers
Rob
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Sent: 28 September 2018 15:05
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Subject: CF-metadata Digest, Vol 185, Issue 47
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Today's Topics:
1. Re: Spectral wave direction spread parameter (Jonathan Gregory)
2. Re: standard names for sea surface roughness variables
(Jonathan Gregory)
3. Re: Spectral wave direction spread parameter (Lowry, Roy K.)
----------------------------------------------------------------------
Message: 1
Date: Fri, 28 Sep 2018 12:26:39 +0000
From: Jonathan Gregory <j.m.gregory at reading.ac.uk>
To: Rob Thomas <Rob.Thomas at Marine.ie>
Cc: "cf-metadata at cgd.ucar.edu" <cf-metadata at cgd.ucar.edu>
Subject: Re: [CF-metadata] Spectral wave direction spread parameter
Message-ID: <20180928122635.GA14743 at met.reading.ac.uk>
Content-Type: text/plain; charset="us-ascii"
Dear Rob
>From the responses it's clear we need a name for this. I'm a bit
>nervous about
"spread", which sounds vague to me. Can you clarify it?
Best wishes and thanks
Jonathan
On Fri, Sep 28, 2018 at 07:47:51AM +0000, Rob Thomas wrote:
> Date: Fri, 28 Sep 2018 07:47:51 +0000
> From: Rob Thomas <Rob.Thomas at Marine.ie>
> To: "cf-metadata at cgd.ucar.edu" <cf-metadata at cgd.ucar.edu>
> Subject: [CF-metadata] Spectral wave direction spread parameter
>
> Hi,
>
>
>
> Please can I propose/request a new standard name for the list:
> "sea_surface_wave_directional_spread_at_variance_spectral_density_maximum"
>
>
>
> The rationale for this request is that in assessing our mappings of spectral wave parameters to the CF standard names we have mapped "Peak Direction" (described as "Dirp Direction for waves at peak of wave energy spectrum from which the waves are coming") to "sea_surface_wave_from_direction_at_variance_spectral_density_maximum" with definition:
>
>
> The quantity with standard name sea_surface_wave_from_direction_at_variance_spectral_density_maximum is the direction from which the most energetic waves are coming. The spectral peak is the most energetic wave in the total wave spectrum. The phrase "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 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.
>
>
>
> It does not appear there is an appropriate partner term for Peak Spread (described as "Dsprp Directional spread of waves at peak of wave energy spectrum") because the options currently available do not appear to tie in to the peak wave energy spectrum/spectral peak information.
>
>
>
> Kind regards,
>
> Rob
>
>
>
> Dr. Rob Thomas
>
> Senior Data Analyst - European Data Management Projects Team Leader
>
>
>
> Marine Institute, Rinville, Oranmore, County Galway, H91 R673, Ireland
>
> Tel: (+)353 (0)91 387 409
>
> Mob: (+)353 (0)87 952 3467
>
> Email: rob.thomas at marine.ie<mailto:rob.thomas at marine.ie>
>
> ORCID: 0000-0001-6068-4924
>
> Web: http://data.marine.ie/
> _______________________________________________
> CF-metadata mailing list
> CF-metadata at cgd.ucar.edu
> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
------------------------------
Message: 2
Date: Fri, 28 Sep 2018 13:45:48 +0100
From: Jonathan Gregory <j.m.gregory at reading.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] standard names for sea surface roughness variables
Message-ID: <20180928124547.GB14743 at met.reading.ac.uk>
Content-Type: text/plain; charset=us-ascii
Dear Andy
> Re the direction of the _mean_square_slope, the parameter and calculation method from the wave spectrum is sufficiently different from that for _wave_[to/from]_direction that it should stand alone. There has already been a precedent set for this with waves, where different forms of parameter calculation from the spectrum are given their own names because there is not only a calculation difference but a different physical interpretation of each parameter (e.g. the various type of wave period).
OK, fair enough. So you need sea_surface_wave_mean_square_slope_to_direction.
I'm still stuck with what this "direction" really is. Can we insert anything else for ? in
sea_surface_wave_mean_square_slope_along_?_direction
sea_surface_wave_mean_square_slope_across_?_direction
Apparently you want to quantify the mean square slope along and across the direction of the mean square slope. Is that right? I'm not sure what it means.
Without the "mean square", I'd think that the slope normal to the direction of the slope must be zero, but it must be more subtle than that in this case!
Is there really an ambiguity of to/from with a mean square slope? It seems to me that it must be the same (unsigned) number regardless of whether you go backwards or forwards on a particular direction.
Is Devon up or down from Cornwall?
Best wishes
Jonathan
------------------------------
Message: 3
Date: Fri, 28 Sep 2018 14:05:06 +0000
From: "Lowry, Roy K." <rkl at bodc.ac.uk>
To: Jonathan Gregory <j.m.gregory at reading.ac.uk>, Rob Thomas <Rob.Thomas at Marine.ie>
Cc: "cf-metadata at cgd.ucar.edu" <cf-metadata at cgd.ucar.edu>
Subject: Re: [CF-metadata] Spectral wave direction spread parameter
Message-ID:
<MM1P123MB13543B8AFDDD9AC7804E136899EC0 at MM1P123MB1354.GBRP123.PROD.OUTLOOK.COM>
Content-Type: text/plain; charset="windows-1252"
Dear Jonathan,
I seem to remember the 'what is spread' discussion coming up last time we encountered wave directional spread Standard Names. The Standard Name sea_surface_wave_directional_spread has the definition:
Directional spread is the (one-sided) directional width within a given sub-domain of the wave directional spectrum, 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. For a given mean wave (beam) direction the quantity approximates half the root mean square width about the beam axis, as derived either directly from circular moments or via the Fourier components of the wave directional spectrum.
This seems to have been omitted from Rob's definition, which should I think read:
The quantity with the Standard Name sea_surface_wave_directional_spread_at_variance_spectral_density_maximum is the directional spread of the most energetic waves. Directional spread is the (one-sided) directional width within a given sub-domain of the wave directional spectrum, 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. For a given mean wave (beam) direction the quantity approximates half the root mean square width about the beam axis, as derived either directly from circular moments or via the Fourier components of the wave directional spectrum.
Cheers, Roy.
I have now retired but will continue to be active through an Emeritus Fellowship using this e-mail address.
________________________________
From: CF-metadata <cf-metadata-bounces at cgd.ucar.edu> on behalf of Jonathan Gregory <j.m.gregory at reading.ac.uk>
Sent: 28 September 2018 13:26
To: Rob Thomas
Cc: cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] Spectral wave direction spread parameter
Dear Rob
>From the responses it's clear we need a name for this. I'm a bit
>nervous about
"spread", which sounds vague to me. Can you clarify it?
Best wishes and thanks
Jonathan
On Fri, Sep 28, 2018 at 07:47:51AM +0000, Rob Thomas wrote:
> Date: Fri, 28 Sep 2018 07:47:51 +0000
> From: Rob Thomas <Rob.Thomas at Marine.ie>
> To: "cf-metadata at cgd.ucar.edu" <cf-metadata at cgd.ucar.edu>
> Subject: [CF-metadata] Spectral wave direction spread parameter
>
> Hi,
>
>
>
> Please can I propose/request a new standard name for the list:
> "sea_surface_wave_directional_spread_at_variance_spectral_density_maximum"
>
>
>
> The rationale for this request is that in assessing our mappings of spectral wave parameters to the CF standard names we have mapped "Peak Direction" (described as "Dirp Direction for waves at peak of wave energy spectrum from which the waves are coming") to "sea_surface_wave_from_direction_at_variance_spectral_density_maximum" with definition:
>
>
> The quantity with standard name sea_surface_wave_from_direction_at_variance_spectral_density_maximum is the direction from which the most energetic waves are coming. The spectral peak is the most energetic wave in the total wave spectrum. The phrase "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 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.
>
>
>
> It does not appear there is an appropriate partner term for Peak Spread (described as "Dsprp Directional spread of waves at peak of wave energy spectrum") because the options currently available do not appear to tie in to the peak wave energy spectrum/spectral peak information.
>
>
>
> Kind regards,
>
> Rob
>
>
>
> Dr. Rob Thomas
>
> Senior Data Analyst - European Data Management Projects Team Leader
>
>
>
> Marine Institute, Rinville, Oranmore, County Galway, H91 R673, Ireland
>
> Tel: (+)353 (0)91 387 409
>
> Mob: (+)353 (0)87 952 3467
>
> Email: rob.thomas at marine.ie<mailto:rob.thomas at marine.ie>
>
> ORCID: 0000-0001-6068-4924
>
> Web: http://data.marine.ie/
data.marine.ie - Marine Environment<
http://data.marine.ie/>
data.marine.ie
Marine Environment The investigation of Marine environments, Open Ocean, deep-sea, estuarine, coastal and near-shore zones and mans? impact on these areas.
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