[Seavox] FW: L06 extensions

[Lowry, Roy K.]

Should have replied to the list, not just John....

________________________________
From: Lowry, Roy K.
Sent: 12 August 2013 08:19
To: John Graybeal
Subject: RE: [Seavox] L06 extensions

Hi John,

I think we're on different wavelengths regarding the gliders.  What I'm trying to distinguish - following your initial suggestion - are gliders whose spatio-temporal feature type may be reasonably be considered a 2D trajectory (i.e. having a single nominal depth in metadata works) from those where the feature type needs to be a 3D trajectory (i.e. the data make no sense without a depth co-ordinate variable).  You obviously didn't get this from my definitions. The need to surface didn't come into it. If I replace 'within the water column' by 'at variable depths significantly below the surface' does that make it clearer?

A drogue is an underwater parachute attached at a depth of around 40m to surface drifting buoys to encourage them to follow the motion of the water rather than the surface winds.  I considered this to be a well-known term - it's certainly well used by people I know.  Admittedly 'undrogued' is an adaptation of the word that won't be found in the Oxford English Dictionary, but it is creeping into common usage in the operational oceanography community. According to JCOMMOPS it is critical to the definition.  I'll clarify by adding '(no underwater parachute)' unless anybody else objects.

I inherited the sea ice definitions (via Mathieu at JCOMMOPS) from The Canadian Ice Service of Environment Canada, but rephrased them slightly - possibly not very well. Can anybody provide me with improved wording?

Cheers, Roy.

________________________________
From: seavox-bounces at mailman.nerc-liv.ac.uk [seavox-bounces at mailman.nerc-liv.ac.uk] On Behalf Of John Graybeal [jbgraybeal at mindspring.com]
Sent: 09 August 2013 16:59
To: seavox at mailman.nerc-liv.ac.uk
Subject: Re: [Seavox] L06 extensions

A few thoughts.

3C and 27 are difficult to distinguish. No gliders are exclusively on the sea surface, if by 'glider' we mean a system that uses buoyancy to initiate forward motion. They are all able to operate within the water column.  So I might say
3C: A platform with buoyancy-based propulsion that routinely surfaces to meet its objectives.
27: A platform with buoyancy-based propulsion that can routinely meet its mission objectives without surfacing.
These are then mutually exclusive.

49: The term 'undrogued' is unfamiliar to me, and to my 3 buddies with ocean background. Looking it up seems to product multiple definitions. Any chance we could be more specific? Or perhaps it isn't critical to the definition?

93/94: 'covering over/under 70% of the sea surface' -- at what scale is this metric assessed? I assume we don't mean of the _entire_ sea surface, but we don't mean of the sea surface within 1 meter, either.

John





On Aug 1, 2013, at 05:49, "Lowry, Roy K." <rkl at bodc.ac.uk<mailto:rkl at bodc.ac.uk>> wrote:

Dear All,

Discussions on this have gone quiet, so I'll summarise what has been said into a proposal for change:

New codes:

CODE: 3C
Preferred Label: surface gliders
Definition: A platform with buoyancy-based propulsion that is confined to operation on the sea surface.
Mapping: broadMatch to surface autonomous vehicle

CODE: 27
Preferred Label: sub-surface gliders
Definition: A platform with buoyancy-based propulsion that is able to operate within the water column.
Mapping: broadMatch to autonomous underwater vehicle

CODE: 49
Preferred Label:  surface ice buoy
Definition: An undrogued surface float that is deployed in regions where sea ice forms that moves with either ice or water depending upon the time of year.
Mapping: broadMatch drifting surface float

CODE: 93
Preferred Label: pack ice
Definition: Sea ice not connected to land covering over 70% of the sea surface.
Mapping: broadMatch cryosphere

CODE: 94
Preferred Label: drift ice
Definition: Sea ice not connected to land covering under 70% of the sea surface.
Mapping: broadMatch cryosphere

If there are no further comments I'll add these records to the vocabulary when I return from leave on August 20th.

Cheers, Roy.



Please note that I now work part-time from Tuesday to Thursday.  E-mail response on other days is possible but not guaranteed!



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