Jonathan Gregory wrote:
>If the defining characteristic of the skin and subskin layers are their depths,
>could we not give them the name of sea_water_temperature, and distinguish them
>by their depth coordinate? The bounds of the depth coordinate for the subskin
>later are 1.0-1.5 mm, and for the skin layer of 10-20 micrometer. If we do that
>we don't need new standard names.
>
>
I like using the single standard name sea_water_temperature, and using the
depth coordinate *and other attributes* to define the layer and the
method of
acquisition. To create new standard names when attributes and coordinate
variables will do the same work does not seem like a good way to use
NetCDF.
Defining the attributes needed to adequately describe the technique is
not *yet*
part of CF, but needs to be thought out pretty carefully, if this route
is taken instead
of always adding to the list of standard names.
If the depth depends on factors such as
instrumentation/frequency/conditions,
maybe we need to change the current requirement that there must be a
numeric
z value for sea_water_temperature and define terms that will adequately
describe
the depth of the values.
Alison Pamment wrote:
> Yes, I did wonder about taking the approach you are suggesting,
> but there are really two defining "coordinates" for these quantities:
> layer depth and frequency range. We could use the
> sea_water_temperature name and require that both depth and
> frequency are supplied as coordinate bounds.
Not sure under what conditions you'd require frequency, since this isn't
appropriate for some (specifically, directly measured) temperature values.
If I were trying to intuit the difference between data labeled with
the std names surface_temperature and sea_surface_temperature,
I would never guess that one is skin temp and that S_S_T is
exclusively sub-skin temperatures. Although this is spelled out in the
definition, it breaks the rule of CF being self-explanatory.
> sea_surface_temperature:
> Sea surface temperature is usually abbreviated as "SST". It is the
> temperature of sea water near the surface, and not the skin
> temperature, whose standard name is surface_temperature.
> For the temperature of sea water at a particular depth or
> layer, a data variable of sea_water_temperature with a vertical
> coordinate axis should be used.
Alison Pamment wrote:
> On the other hand, if these two particular quantities are commonly
> used remote sensing products whose definition never varies perhaps
> they should have distinct standard names. I think the deciding
> factor should be whether it is likely that other, similar quantities
> are likely to be needed in the future with slightly different
> depth/frequency characteristics.
As soon as we decide that something "never varies" there will be a new
development in the technology, and a new standard name will be
needed.
Roy Lowry wrote:
> I currently think we'd be better finding words to explicitly specify
> the layers measured. 'skin' and 'sub-skin' work for me provided they
> are covered by accompanying definitions, but self-defining
> alternatives like 'micowave_penetrated_layer_sst' may be a better
> option.
I don't object to skin and sub-skin, or skin and surface, but when you get
into microwave_penetrated, I think attributes are a more efficient way
to use NetCDF. Should we be looking for a sensor dictionary that might
be adopted by CF?
Cheers - Nan
--
**************************************************************
* Nan Galbraith Upper Ocean Processes Group *
* Woods Hole Oceanographic Institution Woods Hole, MA 02540 *
* http://uop.whoi.edu (508) 289-2444 *
**************************************************************
Received on Wed Jul 25 2007 - 06:51:55 BST
