```Hi Nan,

I agree expanding on the existing standard name descriptions does make sense
and standardising for _rate and _angle```
```
What you suggest below seems acceptable

Thanks

Steve

-----Original Message-----
Sent: 10 July 2018 17:39

Hi Alison, Steve, and all -

Since we have a little time to finalize this, could we also consider updating
the definitions of platform_pitch_angle, platform_roll_angle and
platform_yaw_angle?

Currently, these all say 'Standard names for platform describe the motion and
orientation of the vehicle from which observations are made e.g. aeroplane,
ship or satellite.'

https://en.wikipedia.org/wiki/Ship_motions. The suggestions below are merged
from different sections of that page, and might be a little ... long, but I'd
also like to append something like 'Platforms include but are not limited to
satellites, aeroplanes, ships, instruments, and buoys.'

Pitch
The up/down rotation of a platform about its transverse/Y axis. The
transverse/Y axis, lateral or pitch axis is an imaginary line running
horizontally across the platform and through its center of gravity. A pitchÂ
motion is an up-or-down movement of the bow and stern of the platform.

Roll
The tilting rotation of a platform about its longitudinal/X axis. The
longitudinal/X axis, or roll axis, is an imaginary line running horizontally
through the length of the platform, through its center of gravity, and parallel
to the waterline. A roll motion is a side-to-side or port-starboard tilting
motion of the superstructure around this axis.

Yaw
The turning rotation of a platform about its vertical/Z axis. The vertical/Z
axis, or yaw axis, is an imaginary line running vertically through the platform
and through its center of gravity.
A yaw motion is a side-to side movement of the bow and stern of the ship.

And we had something like this for heave:
platform_heave (m) = upwards vertical displacement

I suppose these could also be applied to platform_*_rates.

Regards -
Nan

On 7/4/18 4:47 AM, Alison Pamment - UKRI STFC wrote:

> Dear Steve,  > > Thank you for your message and apologies for not
> having processed
> your proposals as yet. I have been working on the CMIP names, but > they are
> reaching a conclusion and I will shortly be looking through > the many other
> proposals that have been waiting for attention. > > A quick look through the
> discussion of your names shows they are > pretty much agreed. You need take
> no further action at this time - I > will check that the names and
> definitions are clear and consistent > with existing names and get back to
> you on the list with any final > comments or questions. Version 56 of the
> standard name table will be > published later today - I think we can
> probably finalise your names > in time for version 57. > > Best wishes,
> Alison
> ________________________________
> From: Hamilton, Steve <sj.hamil...@fugro.com>
> Sent: 03 July 2018 09:12
>
>
> Please can you advise if this standard name has now been accepted and
> when it will be included in the CF Standard Names
>
> If there is something else to do please let me know
>
> Thanks
>
> Steve
>
>
> ________________________________
> From: Jim Biard <jbi...@cicsnc.org<mailto:jbi...@cicsnc.org>>
> Sent: 01 June 2018 22:56
>
>
> Nan,
> Thanks for pulling things back in. I very much like the idea of keeping
> technology or specific methods out of the definition if at all possible, so I
> like your proposal. I expect we should include platform in the definition, as
> well as an indication that this is dynamic (over time). How about these
> definitions?
> platform_heave (m) = upwards vertical displacement of a platform over
> a measurement time interval platform_heave_rate (m s-1) = upwards rate
> of change in vertical displacement of a platform over a measurement time
> interval They leave out some detail but capture the relative nature of the
> quantities.
> (In my mind, the primary detail being left out is the 'net zero'
> nature of the quantities, which gets back to defining the
> 'moving-mean' sea level reference point.) Grace and peace,
>
> Jim

> On 6/1/18 11:23 AM, Nan Galbraith wrote:
> Hi all -
>
> The latest version is confusing to me. The term 'a platform that is
> nominally at rest' does not apply to many platforms for which heave is
> calculated; the original version of that, 'a moving object above the
> vertical level of that object when stationary' was maybe a little more
> clear... if also a little wordy.
>
> And, the term  'vertical displacement determined by integrating
> vertical accelerations' may also not apply - I've been looking at the
> different ways heave is calculated, and there are a few: 'Heave can be
> computed from GPS RTK height measurements and from vertical accelerations
> measured by linear accelerometers'
>
> Why  not keep it simple: platform_heave (m) = upwards vertical
> displacement?  Do we need to be more specific than that?
>
> Thanks - Nan
>
>
> From: Lowry, Roy K.
> Sent: 30 May 2018 21:37
>
> An afterthought. Heave is conventionally positive upwards so to make this
> clear I would add the word 'upwards' thus:
>
> platform_heave (m) = upwards vertical displacement determined by integrating
> vertical accelerations of a platform that is nominally at rest.
>
> platform_heave_rate (m s-1) = upwards vertical velocity determined by
> integrating vertical accelerations of a platform that is nominally at rest.
>
> Cheers. Roy.
>
>
> ----------------------------------------------------------------------
> --
>
> From: Lowry, Roy K. <r...@bodc.ac.uk<mailto:r...@bodc.ac.uk>
> Sent: 30 May 2018 21:02
>
> Thanks Jim,
>
> That work for me.
>
> Cheers, Roy.
>
> ----------------------------------------------------------------------
> --
>
> From: Jim Biard <jbi...@cicsnc.org>
> Sent: 30 May 2018 18:39
>
> Roy,
>
> So, heave is integrated vertical acceleration? How about
>
> platform_heave (m) = vertical displacement determined by integrating vertical
> accelerations of a platform that is nominally at rest.
>
> platform_heave_rate (m s-1) = vertical velocity determined by integrating
> vertical accelerations of a platform that is nominally at rest.
>
> Jim
>
> On 5/27/18 5:38 AM, Lowry, Roy K. wrote:
>
>      Hi Jim,
>
>      Does
>
>           "Heave" is a term used to describe the vertical displacement
>          of a moving object above the vertical level of that object
>          when stationary.
>
>      help by getting rid of the semantically-loaded word 'height'?
>      If not, what would?
>
>      I think the confusion is because you are thinking of heave in
>      terms of position within a reference frame. To think of it as the
>      vertical displacement between a real platform and a massless
>      platform is misleading- such considerations are part of the
>      derivation of wave height from high frequency heave measurements,
>      which isn't relevant to a discussion of the raw measurement. It's
>      also worth bearing in mind that whilst the debate has focused on
>      platforms floating on the sea surface, the concept of heave could
>      in theory be applied to objects in the atmosphere.
>
>      In practice, heave is measured by accelerometers that are usually
>      combined with tilt sensors that give pitch, roll and yaw. Hence,
>      it is totally decoupled from any reference outside the platform.
>
>      To answer your last muse, to get heave from a high frequency
>      height relative to datum time series the method would need to
>      determine the height of the object when 'stationary'. In the case
>      of objects on the sea, 'stationary' is considered to be a flat
>      calm sea (i.e. no waves), which can be approximated by averaging
>      the raw time series. So, heave could be approximated by
>      differencing the raw and averaged data. However, I can't think why
>      anybody would want to do that.
>
>      Cheers, Roy.
>
>
> ----------------------------------------------------------------------
> --
>
>      From:Jim Biard <jbi...@cicsnc.org><mailto:jbi...@cicsnc.org>
>      Sent: 26 May 2018 23:18
>
>      My biggest concern is that the standard name definition makes it
>      clear in some fashion or other that this is a measure of
>      deviations from some lower frequency (or low-pass filtered)
>      measure of vertical position. (As are sway and surge in relation
>      to their corresponding horizontal coordinates.) As was pointed
>      out, heave is used in certain communities, so it's reasonable to
>      provide a standard name, but it seems rather imprecise as it has
>      been described so far.
>
>      If I have understood the explanations correctly, a time series of
>      platform height relative to a fixed datum that has sufficient
>      precision and frequency would fully represent the heave along with
>      the more slowly varying effects of tide, waves, etc. So is heave,
>      as usually used, the first-order instantaneous difference between
>      the height of an actual platform and the height of a massless
>      ideal platform that would maintain a fixed offset relative to the
>      sea surface? And, just out of curiosity, how would a time series
>      of instantaneous measures of height relative to a fixed datum be
>      separated in practice into heave and "non-heave" height?
>
>      Getting back on track, it seems to me that the definition ought to
>      somehow assist the reader in understanding how heave relates to
>      other measures of height.
>
>
>      On Sat, May 26, 2018 at 3:11 AM, Lowry, Roy K. wrote:
>
>          Dear Jim and John,
>
>          Heave is indeed a height relative to a datum, that datum being
>          the calm sea surface, which is a local short interval mean sea
>          level that isn't linked into any global reference system.
>          Indeed the 'datum' moves relative to the rest of the world -
>          but not the platform - as tide rises and falls so many would
>          prefer to call it an 'instrument zero' rather than a 'datum'.
>
>          Heave is therefore a very different measurement to any sea
>          level parameter and is the raw measurement recorded at high
>          (Hz to kHz) frequency as a time series by floating wave
>          instruments such as waveriders and shipborne wave recorders.
>          It therefore cannot be sensibly described by the same or
>          similar Standard Name as a measurement of height above a
>          globally referenced datum like long-term mean sea level or
>          geoid. Whilst the Standard Name could be
>          'platform_height_above_calm_sea_surface' or
>          'platform_height_above_stationary_position' I would argue that
>          'heave' is a term from the same domain vocabulary as 'pitch',
>          'roll' and 'yaw' and therefore should be used.
>
>          John is right to point out that the heave measurement is
>          affected by the nature of the platform with a 250,000 tonne
>          supertanker moving up and down much less than a rowing boat in
>          a given wave climate, especially a wind sea. That was what was
>          behind the SBWR corrections based on platform dimensions set
>          up by Laurie Draper and Tom Tucker back in the 1980s.
>
>          Cheers, Roy.
>
>
> ----------------------------------------------------------------------
> --
>
>          From: John Helly <hel...@ucsd.edu>
>          Sent: 26 May 2018 04:48
>
>          Can't let go of this yet.
>
>          If you think about the inverse problem of deriving the sea
>          surface elevation from the heave you would have to account for
>          the latency of ship motion relative to the sea-surface. A
>          wave passing under a ship induces motions that are not
>          instantaneous either in attack or decay.
>
>          J.
>
>          On 5/25/18 20:42, John Helly wrote:
>
>              I believe it's a synonym within the oceanographic
>              community for the vertical motion of an ocean-going platform.
>
>              https://en.wikipedia.org/wiki/Ship_motions
>
>              Ship motions - Wikipedia
>
> <https://en.wikipedia.org/wiki/Ship_motions><https://en.wikipedia.org/
> wiki/Ship_motions>
>
>              en.wikipedia.org
> <http://en.wikipedia.org><http://en.wikipedia.org>
>
>              Ship motions are defined by the six degrees of freedom
>              that a ship, boat or any other craft can experience.
>
>              Could just be jargon but it strike me as more complex:
>              nonetheless a vertical position relative to a datum, but
>              the buoyancy, stability and momentum of the platform are
>              implied as part of the dynamics.  It seems that the datum
>              is not a geophysical one alone but confounded with the
>              'normal' waterline for a platform so it may be relative to
>              the water level in which the platform is embedded. That's
>              a tough one. Two different platforms on the same sea
>              surface would have different 'heave', for example.
>
>              J.
>
>              On 5/25/18 19:54, Jim Biard wrote:
>
>                  Hi.
>
>                  I get and endorse the need for pitch, roll, and yaw,
>                  but I remain perplexed about heave. How is a time
>                  series of 'heave' different from a time series of
>                  height relative to some vertical datum? I've yet to
>                  see a proposed definition that convinces me that this
>                  is a uniquely different quantity.
>
>                  Grace and peace,
>
>                  Jim
>
>
>
>                  On Fri, May 25, 2018 at 7:28 AM, Lowry, Roy K.
>                  <r...@bodc.ac.uk<mailto:r...@bodc.ac.uk> wrote:
>
>                      Dear All,
>
>                      I agree with Nan that definitions of pitch roll
>                      and yaw would improve the existing Standard Name
>                      definitions. I also agree with using the existing
>                      orientation Standard Names for ADCPs and that the
>                      'platform' definition wording could make this
>                      clearer. However, such an enhancements should be
>                      submitted as a separate proposal and not be
>                      considered as part of Steve's proposal.
>
>                      Cheers, Roy.
>
>
> ----------------------------------------------------------------------
> --
>
>                      From:  Nan Galbraith <ngalbra...@whoi.edu>
>                      Sent: 25 May 2018 14:46
>
>
>                      I'd really like to see pitch, roll and yaw defined
>                      in the CF standard name table; currently
>                      the definitions only say 'Standard names for
>                      platform describe the motion and orientation
>                      of the vehicle from which observations are made
>                      e.g. aeroplane, ship or satellite.'
>
>                      Also, not to get too far into the weeds, but many
>                      of the platform terms are important
>                      for instruments like ADCPs, so I'd just like to
>                      confirm that these definitions - and
>                      the names themselves - can be used to describe
>                      instruments, not just vehicles
>                      'e.g. aeroplane, ship or satellite'. We already
>                      use pitch roll and yaw for these
>                      instruments on surface moorings, and I hope (and
>                      assume) this is legal.
>
>                      Thanks - Nan Galbraith
>
>
>                      On 5/25/18 8:53 AM, Lowry, Roy K. wrote:
>                      >
>                      >
>                      > Dear Steve,
>                      >
>                      >
>                      > One of the reasons I was interested in your
>                      definitions was your
>                      > perspective on the datum (i.e. zero value) for
>                      heave. The datum
>                      > 'mean_sea_level' is well used in CF, but with
>                      the definition 'time
>                      > mean of sea surface elevation at a given
>                      location over an arbitrary
>                      > period sufficient to eliminate the tidal
>                      signals.' This is obviously
>                      > not appropriate for platform heave which doesn't
>                      take any account of
>                      > the state of the tide and so I would exclude
>                      'mean_sea_level' from the
>                      > Standard Name.
>                      >
>                      >
>                      > I think my preference would be to keep the term
>                      > have 'pitch', 'yaw' and 'roll', giving:
>                      >
>                      >
>                      > platform_heave (m)
>                      >
>                      >
>                      > Standard names for platform describe the motion
>                      and orientation of the
>                      > vehicle from which observations are made e.g.
>                      aeroplane, ship or
>                      > satellite. "Heave" is a term used to describe
>                      the vertical
>                      > displacement of the platform above its position
>                      when not moving.
>                      >
>                      >
>                      > tendency_of_platform_heave (m s-1)
>                      >
>                      >
>                      > Standard names for platform describe the motion
>                      and orientation of the
>                      > vehicle from which observations are made e.g.
>                      aeroplane, ship or
>                      > satellite. "Tendency_of_X" means derivative of X
>                      with respect to time.
>                      > "Heave" is a term used to describe the vertical
>                      displacement of the
>                      > platform above its position when not moving.
>                      >
>                      >
>                      > What do you think?
>                      >
>                      >
>                      > Cheers, Roy.
>
>
>
>
--
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* Upper Ocean Processes Group            Mail Stop 29 *
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