Hi John,
I touched on this issue when the sea floor temperature and practical salinity names were set up. My understanding is that it does have a meaning which is the portion of the water column influenced by the seabed, sometimes termed the 'benthic boundary layer'. Oceanographers I've worked with certainly of a conceptual understanding of this, but what it means in terms of a quantitative definition varies depending upon whether one is working in shelf sea, deep ocean or other environments.
I think I suggested adding 'benthic boundary layer' to the CF sea_floor Standard Name definitions, but I don't recall any reaction.
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 John Graybeal <jgraybeal at stanford.edu>
Sent: 12 November 2019 23:07
To: Marcelo Andrioni <marceloandrioni at gmail.com>
Cc: CF Metadata List <cf-metadata at cgd.ucar.edu>
Subject: Re: [CF-metadata] Suggestion for standard names for bottom current and due to tides and Stokes drift
I have a question about the definitions of the *_at_sea_floor standard names, which state "? is that adjacent to the ocean bottom, which would be the deepest grid cell in an ocean model."
I understand what this means for ocean models (but suspect it has quite different implications for models featuring cells of smaller thickness nearer the boundary).
Does it mean anything for observational data? (In which case, there should be a corresponding definition, yes?) Or by definition, are all of these variables not applicable to observational data?
This question is general and should not affect this particular request, so conceivably it should be a new topic if the answer is not straightforward.
John
On Nov 12, 2019, at 11:59 AM, Marcelo Andrioni <marceloandrioni at gmail.com<mailto:marceloandrioni at gmail.com>> wrote:
Dear Jonathan, my suggestion of sea_water_from_direction_at_sea_floor
was based on the "basic" standard name:
sea_water_from_direction
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.
so that the only difference would be to add the suffix _at_sea_floor
like it was done with:
sea_water_potential_temperature
sea_water_potential_temperature_at_sea_floor
Thank you.
Em ter., 12 de nov. de 2019 ?s 16:22,
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Today's Topics:
1. Suggestion for standard names for bottom current and due to
tides and Stokes drift (Jonathan Gregory)
2. Re: Suggestion for standard names for bottom current and due
to tides and Stokes drift (Marcelo Andrioni)
----------------------------------------------------------------------
Message: 1
Date: Mon, 11 Nov 2019 18:00:27 +0000
From: Jonathan Gregory <j.m.gregory at reading.ac.uk<mailto:j.m.gregory at reading.ac.uk>>
To: "cf-metadata at cgd.ucar.edu<mailto:cf-metadata at cgd.ucar.edu>" <cf-metadata at cgd.ucar.edu<mailto:cf-metadata at cgd.ucar.edu>>
Subject: [CF-metadata] Suggestion for standard names for bottom
current and due to tides and Stokes drift
Message-ID: <20191111180025.GA8846 at met.reading.ac.uk<mailto:20191111180025.GA8846 at met.reading.ac.uk>>
Content-Type: text/plain; charset="us-ascii"
Dear Francesca and Marcelo
I think that "velocity" ought to appear in this one:
sea_water_to_direction_at_sea_floor
It's the velocity which has a direction.
Best wishes
Jonathan
----- Forwarded message from Francesca Eggleton - UKRI STFC <francesca.eggleton at stfc.ac.uk<mailto:francesca.eggleton at stfc.ac.uk>> -----
Date: Mon, 11 Nov 2019 17:29:31 +0000
From: Francesca Eggleton - UKRI STFC <francesca.eggleton at stfc.ac.uk<mailto:francesca.eggleton at stfc.ac.uk>>
To: "cf-metadata at cgd.ucar.edu<mailto:cf-metadata at cgd.ucar.edu>" <cf-metadata at cgd.ucar.edu<mailto:cf-metadata at cgd.ucar.edu>>
Subject: [CF-metadata] Suggestion for standard names for bottom current and
due to tides and Stokes drift
Dear Marcelo,
Thank you for your proposals and apologies for the delay in responding. As you may have seen in Alison's last email, I will be helping out with the maintenance of the standard names.
Thank you to Jonathan for comments on these proposals. They all look good and seem to match what already exists. The two phrases which were suggested as aliases, I believe to be new terms and have suggested a reason why so please comment if you agree/disagree. The following text will list each of the proposals, their units and descriptions (constructed from similar terms to be in line with standard name descriptions). Please let me know if there are any comments or further changes to be made. If no comments are made in the next 7 days, these are likely to be accepted in the next update.
eastward_sea_water_velocity_at_sea_floor
ms-1
A velocity is a vector quantity. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). The velocity at the sea floor is that adjacent to the ocean bottom, which would be the deepest grid cell in an ocean model.
northward_sea_water_velocity_at_sea_floor
ms-1
A velocity is a vector quantity. "Northward" indicates a vector component which is positive when directed northward (negative southward). The velocity at the sea floor is that adjacent to the ocean bottom, which would be the deepest grid cell in an ocean model.
sea_water_to_direction_at_sea_floor
degree
The phrase "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. The direction at the sea floor is that adjacent to the ocean bottom, which would be the deepest grid cell in an ocean model.
sea_water_speed_at_sea_floor
ms-1
Speed is the magnitude of velocity. The speed at the sea floor is that adjacent to the ocean bottom, which would be the deepest grid cell in an ocean model.
eastward_sea_water_velocity_due_to_tides
ms-1
A velocity is a vector quantity. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). 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. "Due to tides" means due to all astronomical gravity changes which manifest as tides. No distinction is made between different tidal components.
northward_sea_water_velocity_due_to_tides
ms-1
A velocity is a vector quantity. "Northward" indicates a vector component which is positive when directed northward (negative southward). 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. "Due to tides" means due to all astronomical gravity changes which manifest as tides. No distinction is made between different tidal components.
sea_water_to_direction_due_to_tides
degree
The phrase "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. 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. "Due to tides" means due to all astronomical gravity changes which manifest as tides. No distinction is made between different tidal components.
sea_water_speed_due_to_tides
ms-1
Speed is the magnitude of velocity. 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. "Due to tides" means due to all astronomical gravity changes which manifest as tides. No distinction is made between different tidal components.
The following should not be aliases of sea_surface_wave_stokes_drift_x_velocity and sea_surface_wave_stokes_drift_y_velocity, they should be proposed as new terms. The definition states '"x" indicates a vector component along the grid x-axis, positive with increasing x.', this has been done on purpose to allow this term to be used with any type of grid and not limiting it to a lat-lon grid. The term eastward is defined as '"Eastward" indicates a vector component which is positive when directed eastward (negative westward)' which limits this term to being 'zonal' (along a latitudinal circle).
sea_surface_wave_stokes_drift_eastward_velocity
ms-1
A velocity is a vector quantity. "Eastward" indicates a vector component which is positive when directed eastward (negative westward). The Stokes drift velocity is the average velocity when following a specific fluid parcel as it travels with the fluid flow. For instance, a particle floating at the free surface of water waves, experiences a net Stokes drift velocity in the direction of wave propagation.
sea_surface_wave_stokes_drift_northward_velocity
ms-1
A velocity is a vector quantity. "Northward" indicates a vector component which is positive when directed northward (negative southward). The Stokes drift velocity is the average velocity when following a specific fluid parcel as it travels with the fluid flow. For instance, a particle floating at the free surface of water waves, experiences a net Stokes drift velocity in the direction of wave propagation.
sea_surface_wave_stokes_drift_to_direction
degrees
The Stokes drift velocity is the average velocity when following a specific fluid parcel as it travels with the fluid flow. For instance, a particle floating at the free surface of water waves, experiences a net Stokes drift velocity in the direction of wave propagation. The phrase "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.
sea_surface_wave_stokes_drift_speed
ms-1
The Stokes drift velocity is the average velocity when following a specific fluid parcel as it travels with the fluid flow. For instance, a particle floating at the free surface of water waves, experiences a net Stokes drift velocity in the direction of wave propagation. Speed is the magnitude of velocity.
Thank you,
Francesca Eggleton
Graduate Environmental Data Scientist
Normal Working Hours (Mon-Thurs): 9am-5pm (Fri 4:30pm)
RAL Space | R25 | Ext: 6710
Centre for Environmental Data Analysis (CEDA)
Science and Technology Facilities Council (STFC)
Rutherford Appleton Laboratory | Harwell Campus
Didcot | OX11 0QX
www.ceda.ac.uk<
http://www.ceda.ac.uk><
http://www.ceda.ac.uk/>
[cid:image001.jpg at 01D4F05B.30A11420][cid:image001.png at 01D590AB.EC504AB0]
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Dear Marcelo
These look fine to me, thanks. Just to be clear - you're *not* proposing
at_bottom, are you? I agree with you that at_sea_floor would be the right
phrase to use.
Best wishes
Jonathan
Hello,
I would like to suggest the inclusion of standard names for u, v,
speed and direction for bottom current and due to tides and Stokes
drift:
An example of model output with bottom velocity is the HYCOM NCODA forecast:
https://tds.hycom.org/thredds/catalog/GLBv0.08/expt_93.0/data/forecasts/runs/catalog.html?dataset=GLBv0.08/expt_93.0/data/forecasts/runs/FMRC_RUN_2019-10-13T12:00:00Z
water_u_bottom (m/s) = Eastward Water Velocity =
eastward_sea_water_velocity_at_bottom
water_v_bottom (m/s) = Northward Water Velocity =
northward_sea_water_velocity_at_bottom
based on existing variables:
sea_water_potential_temperature_at_sea_floor
sea_water_temperature_at_sea_floor
sea_water_salinity_at_sea_floor
sea_water_pressure_at_sea_floor
my suggestion would be:
eastward_sea_water_velocity_at_sea_floor
northward_sea_water_velocity_at_sea_floor
sea_water_to_direction_at_sea_floor
sea_water_speed_at_sea_floor
An example of model output with currents due to tides and Stokes drift
is the Mercator Forecast:
http://marine.copernicus.eu/services-portfolio/access-to-products/?option=com_csw&view=details&product_id=GLOBAL_ANALYSIS_FORECAST_PHY_001_024
based on existing variables:
eastward_sea_water_velocity_assuming_no_tide
northward_sea_water_velocity_assuming_no_tide
ocean_vertical_momentum_diffusivity_due_to_tides
ocean_vertical_tracer_diffusivity_due_to_tides
my suggestion would be:
eastward_sea_water_velocity_due_to_tides
northward_sea_water_velocity_due_to_tides
sea_water_to_direction_due_to_tides
sea_water_speed_due_to_tides
Stokes drift is present in the current CF table with:
sea_surface_wave_stokes_drift_x_velocity
sea_surface_wave_stokes_drift_y_velocity
I think it could help to add
sea_surface_wave_stokes_drift_eastward_velocity
sea_surface_wave_stokes_drift_northward_velocity
as aliases to make it clear it is zonal and meridional currents, and
not just along the grid X and Y dimensions.
Thank you very much.
--
Marcelo Andrioni
marceloandrioni at gmail.com<http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata>
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----- End forwarded message -----
------------------------------
Message: 2
Date: Tue, 12 Nov 2019 16:21:43 -0300
From: Marcelo Andrioni <marceloandrioni at gmail.com<mailto:marceloandrioni at gmail.com>>
To: cf-metadata at cgd.ucar.edu<mailto:cf-metadata at cgd.ucar.edu>, francesca.eggleton at stfc.ac.uk<mailto:francesca.eggleton at stfc.ac.uk>
Subject: Re: [CF-metadata] Suggestion for standard names for bottom
current and due to tides and Stokes drift
Message-ID:
<CAECDRdfO-7adUp8XpBWXXEZse49KMtvAFY=F8noi8thqA68QQA at mail.gmail.com<mailto:CAECDRdfO-7adUp8XpBWXXEZse49KMtvAFY=F8noi8thqA68QQA at mail.gmail.com>>
Content-Type: text/plain; charset="UTF-8"
Dear Francesca,
the accompanying explanations of what the variables represent are
perfect, I have nothing to contribute. I also agree with you that:
sea_surface_wave_stokes_drift_eastward_velocity
sea_surface_wave_stokes_drift_northward_velocity
should *not* be aliases for
sea_surface_wave_stokes_drift_x_velocity
sea_surface_wave_stokes_drift_y_velocity
I am glad the new names will be considered for the next update. I have
some more suggestions for new standard names but I will be using the
GitHub issues discussion from now on as instructed
https://github.com/cf-convention/discuss/issues
Thank you very much for your work in maintaining the list.
--
Marcelo Andrioni
marceloandrioni at gmail.com
From: Francesca Eggleton - UKRI STFC <francesca.eggleton at stfc.ac.uk>
To: "cf-metadata at cgd.ucar.edu" <cf-metadata at cgd.ucar.edu>
Subject: [CF-metadata] Suggestion for standard names for bottom
current and due to tides and Stokes drift
Message-ID: <b1ba4ab901f74a8fa48418a9a4c68b64 at stfc.ac.uk>
Content-Type: text/plain; charset="us-ascii"
Dear Marcelo,
Thank you for your proposals and apologies for the delay in
responding. As you may have seen in Alison's last email, I will be
helping out with the maintenance of the standard names.
Thank you to Jonathan for comments on these proposals. They all look
good and seem to match what already exists. The two phrases which were
suggested as aliases, I believe to be new terms and have suggested a
reason why so please comment if you agree/disagree. The following text
will list each of the proposals, their units and descriptions
(constructed from similar terms to be in line with standard name
descriptions). Please let me know if there are any comments or further
changes to be made. If no comments are made in the next 7 days, these
are likely to be accepted in the next update.
eastward_sea_water_velocity_at_sea_floor
ms-1
A velocity is a vector quantity. "Eastward" indicates a vector
component which is positive when directed eastward (negative
westward). The velocity at the sea floor is that adjacent to the ocean
bottom, which would be the deepest grid cell in an ocean model.
northward_sea_water_velocity_at_sea_floor
ms-1
A velocity is a vector quantity. "Northward" indicates a vector
component which is positive when directed northward (negative
southward). The velocity at the sea floor is that adjacent to the
ocean bottom, which would be the deepest grid cell in an ocean model.
sea_water_to_direction_at_sea_floor
degree
The phrase "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. The direction at the sea
floor is that adjacent to the ocean bottom, which would be the deepest
grid cell in an ocean model.
sea_water_speed_at_sea_floor
ms-1
Speed is the magnitude of velocity. The speed at the sea floor is that
adjacent to the ocean bottom, which would be the deepest grid cell in
an ocean model.
eastward_sea_water_velocity_due_to_tides
ms-1
A velocity is a vector quantity. "Eastward" indicates a vector
component which is positive when directed eastward (negative
westward). 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. "Due to tides" means due to all astronomical
gravity changes which manifest as tides. No distinction is made
between different tidal components.
northward_sea_water_velocity_due_to_tides
ms-1
A velocity is a vector quantity. "Northward" indicates a vector
component which is positive when directed northward (negative
southward). 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. "Due to tides" means due to all astronomical
gravity changes which manifest as tides. No distinction is made
between different tidal components.
sea_water_to_direction_due_to_tides
degree
The phrase "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. 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. "Due to
tides" means due to all astronomical gravity changes which manifest as
tides. No distinction is made between different tidal components.
sea_water_speed_due_to_tides
ms-1
Speed is the magnitude of velocity. 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. "Due to tides" means due to all
astronomical gravity changes which manifest as tides. No distinction
is made between different tidal components.
The following should not be aliases of
sea_surface_wave_stokes_drift_x_velocity and
sea_surface_wave_stokes_drift_y_velocity, they should be proposed as
new terms. The definition states '"x" indicates a vector component
along the grid x-axis, positive with increasing x.', this has been
done on purpose to allow this term to be used with any type of grid
and not limiting it to a lat-lon grid. The term eastward is defined as
'"Eastward" indicates a vector component which is positive when
directed eastward (negative westward)' which limits this term to being
'zonal' (along a latitudinal circle).
sea_surface_wave_stokes_drift_eastward_velocity
ms-1
A velocity is a vector quantity. "Eastward" indicates a vector
component which is positive when directed eastward (negative
westward). The Stokes drift velocity is the average velocity when
following a specific fluid parcel as it travels with the fluid flow.
For instance, a particle floating at the free surface of water waves,
experiences a net Stokes drift velocity in the direction of wave
propagation.
sea_surface_wave_stokes_drift_northward_velocity
ms-1
A velocity is a vector quantity. "Northward" indicates a vector
component which is positive when directed northward (negative
southward). The Stokes drift velocity is the average velocity when
following a specific fluid parcel as it travels with the fluid flow.
For instance, a particle floating at the free surface of water waves,
experiences a net Stokes drift velocity in the direction of wave
propagation.
sea_surface_wave_stokes_drift_to_direction
degrees
The Stokes drift velocity is the average velocity when following a
specific fluid parcel as it travels with the fluid flow. For instance,
a particle floating at the free surface of water waves, experiences a
net Stokes drift velocity in the direction of wave propagation. The
phrase "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.
sea_surface_wave_stokes_drift_speed
ms-1
The Stokes drift velocity is the average velocity when following a
specific fluid parcel as it travels with the fluid flow. For instance,
a particle floating at the free surface of water waves, experiences a
net Stokes drift velocity in the direction of wave propagation. Speed
is the magnitude of velocity.
Thank you,
Francesca Eggleton
Graduate Environmental Data Scientist
Normal Working Hours (Mon-Thurs): 9am-5pm (Fri 4:30pm)
RAL Space | R25 | Ext: 6710
Centre for Environmental Data Analysis (CEDA)
Science and Technology Facilities Council (STFC)
Rutherford Appleton Laboratory | Harwell Campus
Didcot | OX11 0QX
www.ceda.ac.uk<http://www.ceda.ac.uk/>
------------------------------
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End of CF-metadata Digest, Vol 199, Issue 3
*******************************************
--
Marcelo Andrioni
marceloandrioni at gmail.com<mailto:marceloandrioni at gmail.com>
_______________________________________________
CF-metadata mailing list
CF-metadata at cgd.ucar.edu
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========================
John Graybeal
Technical Program Manager
Center for Expanded Data Annotation and Retrieval /+/ NCBO BioPortal
Stanford Center for Biomedical Informatics Research
650-736-1632 | ORCID 0000-0001-6875-5360
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