Hi Jonathan,
In my experience ADCP acoustic echo intensity (sometimes termed acoustic
backscatter) is either given as an absolute measurent in decibels or as
a proportion of the transmitted signal, usually expressed as a
percentage. However, it is often very poorly described in data sets and
questions such as yours have solicited some very blank looks from our
data originators!
Sea pressure is a real can of worms. For moored instruments the meaning
of the measurement is VERY different depending on whether the pressure
sensor is bolted to someting solid (gives a meaningful measurement of
sea level) or supported on a wire with sub-surface buoyancy (gives a
measurement of how much morring 'knock-down' occured - i.e. an
engineering parameter). If both of these types of measurement carry the
same standard name label, great care needs to be taken that the mooring
configuration is held somewhere else in the metadata in a form where it
can be used by data discovery portals. If not, users looking for sea
level datasets will end up with a lot of useless hits.
It goes without saying that it is just as important to ensure that CTD
data sets, where sea pressure is often included as the z spatial
co-ordinate, are distinguished from sea level data sets. Otherwise our
sea level user will be absolutely indundated by false hits.
Cheers, Roy.
>>> Jonathan Gregory <j.m.gregory at reading.ac.uk> 03/22/05 7:37 PM >>>
Dear Mike
There isn't any procedure except writing to the email list, as you have
done.
However as increasing numbers of names are being needed, this is
becoming too
slow. We need automatic procedures and more people to work on it! These
issues
will be discussed at a meeting the British Atmospheric Data Centre is
hosting
in June of GO-ESSP (go-essp.gfdl.noaa.gov).
I'm glad you found most of what you need.
I think sea_water_pressure (canonical units Pa) is fine.
Could you say more about ADCP measured acoustic echo intensity? What
units
does it have? I would think that the physical quantity that should be
given
a standard name is the acoustic echo intensity because presumably it is
applicable to other sonar devices as well.
Thanks. Best wishes
Jonathan
_______________________________________________
CF-metadata mailing list
CF-metadata at cgd.ucar.edu
http://www.cgd.ucar.edu/mailman/listinfo/cf-metadata
Received on Fri Apr 01 2005 - 02:33:30 BST
