Let me rephrase my question as a statement. I didn't understand Matthias' original statement about denoting the vertical extent of the measurement (to me, a naive viewer, travel time is simply travel time, and I don't need to understand the vertical extent of the measurement to interpret the number in a naive way. (In *some* cases, the vertical extent could be entirely derived by the travel time, possibly badly of course if you're lacking metadata like density.)
So I imagine metadata is always a good thing, but the definition will need to be more specific about this additional description, if it is to be useful across the wide set of possible applications of this particular parameter type.
John
On May 30, 2013, at 09:49, "Lowry, Roy K." <rkl at bodc.ac.uk> wrote:
> Hi John,
>
> Not exactly. The travel time in both water column echosounding and seismics is a proxy for distance and therefore provides information on the vertical distribution of returned signal intensity.
>
> Cheers, Roy.
>
> ________________________________________
> From: John Graybeal [graybeal at marinemetadata.org]
> Sent: 30 May 2013 15:22
> To: Lowry, Roy K.
> Cc: mlankhorst at ucsd.edu; cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] standard_name for acoustic travel time from echo sounder
>
> +1 for Roy's choice.
>
> Can you explain the following for the acoustically naive? "I assume the data would need some additional description to denote the vertical extent of the measurement, such as cell_bounds and cell_methods='Z:sum'."
>
> John
>
> On May 30, 2013, at 06:45, "Lowry, Roy K." <rkl at bodc.ac.uk> wrote:
>
>> Dear All,
>>
>> Of Matthias's suggestions I have a strong preference for a slight extension of roundtrip_acoustic_travel_time_in_sea_water, namely acoustic_signal_roundtrip_travel_time_in_sea_water. 'two-way' is a possible alternative to 'roundtrip' but I think the former carries unfortunate seismic semantic implications, so 'roundtrip' is better for IES. Including 'in_sea_water' is also essential to clearly distinguish it from seismic data.
>>
>> Cheers, Roy.
>> ________________________________________
>> From: CF-metadata [cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Matthias Lankhorst [mlankhorst at ucsd.edu]
>> Sent: 30 May 2013 13:16
>> To: cf-metadata at cgd.ucar.edu
>> Subject: [CF-metadata] standard_name for acoustic travel time from echo sounder
>>
>> Dear CF,
>>
>> I have oceanographic data from IES instruments (inverted echo sounder) that I
>> would like to publish via OceanSITES in a CF-compliant form. The data in
>> question are acoustic travel times from the echo sounding device. This means
>> the time it took for the acoustic signal to run from the instrument (which
>> sits on the seafloor) to the sea surface and back to the instrument. These
>> data are commonly used as a proxy for ocean heat content.
>>
>> I don't think there is a suitable CF standard_name out there, and ask for your
>> help in finding/creating one. Which of the following sound good?
>>
>> acoustic_travel_time
>> vertical_acoustic_travel_time
>> roundtrip_acoustic_travel_time_in_sea_water
>> echo_sounder_acoustic_travel_time
>>
>> ...I could think of a couple more combinations using the words above, but
>> would like to hear other people's opinions.
>>
>> The canonical units would obviously be seconds.
>>
>> I assume the data would need some additional description to denote the
>> vertical extent of the measurement, such as cell_bounds and
>> cell_methods='Z:sum'.
>>
>> Any comments?
>>
>> Kind regards, Matthias
>>
>>
>> --
>> _______________________________________
>>
>> Dr. Matthias Lankhorst
>> Scripps Institution of Oceanography
>> 9500 Gilman Drive, Mail Code 0230
>> La Jolla, CA 92093-0230
>> USA
>>
>> Phone: +1 858 822 5013
>> Fax: +1 858 534 9820
>> E-Mail: mlankhorst at ucsd.edu
>> http://www-pord.ucsd.edu/~mlankhorst/
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>>
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>
>
> ---------------
> John Graybeal
> Marine Metadata Interoperability Project: http://marinemetadata.org
> graybeal at marinemetadata.org
>
> 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.
>
---------------
John Graybeal
Marine Metadata Interoperability Project:
http://marinemetadata.org
graybeal at marinemetadata.org
Received on Thu May 30 2013 - 11:34:15 BST
