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-boun...@cgd.ucar.edu [cf-metadata-boun...@cgd.ucar.edu] On Behalf Of Nan Galbraith [ngalbra...@whoi.edu] Sent: 04 February 2010 17:29 To: Jonathan Gregory Cc: cf-metadata@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 > -- ******************************************************* * Nan Galbraith (508) 289-2444 * * Upper Ocean Processes Group Mail Stop 29 * * Woods Hole Oceanographic Institution * * Woods Hole, MA 02543 * ******************************************************* _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata -- This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system. _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
