| Nan - Don't get me wrong… I agree with what you have said and the practical point of view, and was seriously just wondering what a statistician would say about this. And of course most (?) or at least many instruments are not directly measuring the thing they are reporting or the thing that is being recorded in the netCDF file… e.g., conductivity is measured not salinity. Pressure not depth…. and so on.
Ken
I don't want to belabor this point, but
from the practical point of view of someone
who uses and generates data, which I think is fairly
representative of this group, a
mean is a representation of a geophysical property, and a stdev is
not.
We collect in situ data, and I know that MANY of our instruments
output the mean
of several measurements, few do single spot samples. It would
surprise me to hear
anyone claim that these data sets do not represent geophysical
quantities.
Again, I'm just suggesting that the rules for standard name
modifiers might be
tweaked to encourage user-friendly labeling of data. I suspect
that most data
publishers are already taking care not to share data that's
labeled in a CF-compliant
but misleading way.
Regards - Nan
On 3/29/13 9:08 AM, Kenneth S. Casey - NOAA Federal wrote:
Nan - your statement below has me wondering about what a
statistician would say. Would they say: A "mean" is still a
statistical concept, and can not be measured. It can only be
computed, statistically, as sum/N. In that sense, it is not
really any different that standard deviation… the mean is where
the distribution is centered, and the standard deviation is the
width of that distribution. Neither is a discrete measurement
and only make sense as part of a distribution. But I am not a
statistician so I really do wonder what one would say….
-Ken
I don't
think the standard deviation of the temperature of sea
water is really a
geophysical property; it's a
mathematical concept, while a temperature value
represented as a mean is still
a temperature.
--
*******************************************************
* Nan Galbraith Information Systems Specialist *
* Upper Ocean Processes Group Mail Stop 29 *
* Woods Hole Oceanographic Institution *
* Woods Hole, MA 02543 (508) 289-2444 *
*******************************************************
Kenneth S. Casey, Ph.D. Technical Director NOAA National Oceanographic Data Center 1315 East-West Highway Silver Spring MD 20910 301-713-3272 x133 http://www.nodc.noaa.gov
 
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