Hello Nan,
I was arguing at the start of this thread that an instantaneous single-beam echosounder measurement is the so close to being the same thing as a BPR measurement in tidal mode with waves filtered out (ever looked at echosounder data from an anchored ship?) that they should be called the same thing on the basis that the Standard Name represents the phenomenon and should not describe how it was measured.
Cheers, Roy.
________________________________________
From: cf-metadata-bounces at cgd.ucar.edu [cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Nan Galbraith [ngalbraith at whoi.edu]
Sent: 04 February 2010 17:29
To: Jonathan Gregory
Cc: cf-metadata at cgd.ucar.edu; Mike Garcia
Subject: Re: [CF-metadata] seeking CF name for total water column height
Sea_floor_depth_below_sea_surface seems very appropriate when
the water depth is measured from the surface.
Some communities need to distinguish this measurement from one
made from the sea floor. Shipboard water depth measurements in the
open ocean generally ignore tides and other variations in sea surface
height, while bottom pressure recorders or other instruments used in
transport studies are monitoring these differences.
The oceansites project is looking for a way to identify this distinction -
maybe having 2 "water depth" terms in CF will be the solution, although
it may not be clear enough (especially since most people seem to think
these terms are synonyms).
If this has been mentioned, please excuse; I've been on a ship with
terrible network throughput, and I'm slowly trying to catch up with
email discussions.
Cheers - Nan
> I agree, it is arbitrary whether it is called
> sea_floor_depth_below_sea_surface
> or
> sea_surface_height_above_sea_floor
> and I agree with Roy that consistency with existing names would suggest
> the former.
>
> It's interesting that this kind of ambiguity hasn't arisen before. What you
> want to name is the distance between two named surfaces. In other names, we
> call the vertical distance between two surfaces a "thickness" e.g.
> ocean_mixed_layer_thickness. That doesn't have an associated "direction"
> (upward or downward) and so avoids this problem. By that analogy the quantity
> you want to name might be called thickness_of_ocean but I suspect most people
> would find that less obvious. What we are aiming at principally is clarity.
>
> The procedure for adding names is that Alison Pamment, the manager of standard
> names, will consider them and add them. She is dealing with CMIP5 names at
> present, I believe, so it might be a while before she gets to this. If no-one
> else objects soon or makes an alternative proposal, I'd suggest you use this
> name on the assumption that it will be added to the stdname table in due
> course.
>
> Best wishes
>
> Jonathan
>
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* Nan Galbraith (508) 289-2444 *
* Upper Ocean Processes Group Mail Stop 29 *
* Woods Hole Oceanographic Institution *
* Woods Hole, MA 02543 *
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Received on Fri Feb 05 2010 - 01:03:23 GMT
