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
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
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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.
I am retiring on 31/05/2018 but will continue to be active through
an Emeritus Fellowship using this e-mail address.
------------------------------------------------------------------------
*From:* CF-metadata <cf-metadata-boun...@cgd.ucar.edu
<mailto:cf-metadata-boun...@cgd.ucar.edu>> on behalf of Nan
Galbraith <ngalbra...@whoi.edu <mailto:ngalbra...@whoi.edu>>
*Sent:* 25 May 2018 14:46
*To:* cf-metadata@cgd.ucar.edu <mailto:cf-metadata@cgd.ucar.edu>
*Subject:* Re: [CF-metadata] Platform Heave
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 'heave' as we
already
> 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.
>
>
> I am retiring on 31/05/2018 but will continue to be active
through an
> Emeritus Fellowship using this e-mail address.
>
>
>
>
------------------------------------------------------------------------
> *From:* CF-metadata <cf-metadata-boun...@cgd.ucar.edu
<mailto:cf-metadata-boun...@cgd.ucar.edu>> on behalf of
> Hamilton, Steve <sj.hamil...@fugro.com
<mailto:sj.hamil...@fugro.com>>
> *Sent:* 25 May 2018 08:51
> *To:* cf-metadata@cgd.ucar.edu <mailto:cf-metadata@cgd.ucar.edu>
> *Subject:* Re: [CF-metadata] Platform Heave
>
> All,
>
> Thanks for all the comments, I have tried to capture as below -
>
> *Parameter Name***
>
>
>
> *Standard Name*
>
>
>
> *Definition*
>
>
>
> *Canonical Units*
>
> Platform Heave
>
>
>
> Platform_Height_above_mean_sea_Level
>
>
>
> Standard names for platform describe the motion and
> orientation of the vehicle from which observations are made e.g.
> aeroplane, ship or satellite. Height above mean sea Level is the
> linear vertical (up/down) distance of the platform in respect to
the
> mean sea level.
>
>
>
> m
>
> Platform Heave Rate
>
>
>
> Tendency_of_Platform_Height_above_mean_sea_Level
>
>
>
> 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. Height above mean sea Level is the linear
> vertical (up/down) distance of the platform in respect to the
mean sea
> level.
>
>
>
> m s-1
>
> Please let me know if you have further comments
>
> Thanks
>
> Steve
>
> *From:*Steven Emmerson <emmer...@ucar.edu
<mailto:emmer...@ucar.edu>>
> *Sent:* 21 May 2018 19:18
> *To:* Hamilton, Steve <sj.hamil...@fugro.com
<mailto:sj.hamil...@fugro.com>>
> *Cc:* cf-metadata@cgd.ucar.edu <mailto:cf-metadata@cgd.ucar.edu>
> *Subject:* Re: [CF-metadata] Platform Heave
>
> Whatever name you come up with, the canonical unit of the heave
rate
> shouldn't be "ms-1", but rather one of the following:
>
> m s-1
>
> m/s
>
> m.s-1
>
> I favor "m/s".
>
>
> Regards,
>
> Steve Emmerson
>
> On Mon, May 21, 2018 at 6:32 AM, Hamilton, Steve
> <sj.hamil...@fugro.com <mailto:sj.hamil...@fugro.com>
<mailto:sj.hamil...@fugro.com>> wrote:
>
> Hi
>
> I am trying to find the CF name for heave of a vessel or
> platform. platform_roll_angle and platform_pitch_angle already
> exist but nothing on heave
>
> Would be the following be acceptable
>
> Platform_heave (m)
>
> Platform_heave_rate (ms-1)
>
> Standard names for platform describe the motion and
orientation of
> the vehicle from which observations are made e.g. aeroplane,
ship
> or satellite.
>
> Kind Regards,
>
> Steve
>
>
--
*******************************************************
* Nan Galbraith Information Systems Specialist *
* Upper Ocean Processes Group Mail Stop 29 *
* Woods Hole Oceanographic Institution *
* Woods Hole, MA 02543 (508) 289-2444 *
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