[CF-metadata] CF standard names for echam5-hammoz model?(aerosol-chemistry-climate)

Roy Lowry rkl at bodc.ac.uk
Tue Nov 18 06:56:34 MST 2008


Hello Jonathan,

Were you saying that um m-3 is dimensionally equivalent to kg m-3 or have I misunderstood? To me changing between these units changes the Standard Name.

We've had this debate with some of the ocean parameters and came to the conclusion that different terms and therefore different Standard Names should be used for the various types of concentration, such as quantity of substance per unit volume, mass per unit volume and so on.

Cheers, Roy.

>>> Jonathan Gregory <j.m.gregory at reading.ac.uk> 11/18/08 1:43 PM >>>
Dear Heinke

> atmosphere_number_content_of_X (new physical parameter)
> 
> This was Jonathan's proposal.
> Christiane talked about _in_air. But I think that does not fit.
> For example _in_cloud is not in_air. Is that right, Christiane?

I think in_cloud is in_air, and I suggested to Christiane using cell_methods
to indicate the cloud portion of the grid box, if that is required. I think
"atmosphere" indicates that the content is a property of the whole atmosphere,
whereas in_air means a local property of the medium. I know this distinction
is not strictly necessary; we have always made it like that because it is
more like the terms that people normally use e.g. density of air, but
energy content of atmosphere.

> _in_air_of_atmosphere_layer
Sorry, I don't understand what this construction means e.g.
> mass_fraction_of_ozone_in_air_of_atmosphere_layer
What is the difference between that and
mass_fraction_of_ozone_in_air?

> We changed the units to micrograms/m3 ...
Any units which are dimensionally equivalent can be specified. CF doesn't say
whether it should be um m-3 or kg m-3. Either could be stated in the standard
name table as the "canonical units" for the quantity, but it is probably best
to be consistent.

> Christiane said:
> There is not exact definition for Aitken, Coarse mode particles, hence I
> would suggest to avoid these names in CF.
> 
> We agree that there isn't clear definition for these aerosol classes.
> Alternative
> could be to give the exact distribution properties in the CF name, for
> example coarse
> mode can be described as particles with number median radius greater
> than 0.5 micrometers.
> 
> Could we use a scalar coordinate variable for the radius?
Yes, we could. But for other size classes, Christiane did use names e.g. pm10.

> atmosphere_aerosol_refractive_index_imaginary_part
etc.
Could we say imaginary_part_of_atmosphere_aerosol_refractive_index or
atmosphere_aerosol_imaginary_refractive_index?
? I think it would be better to have the "imaginary" before the "refractive
index" somehow. This is a bit like eastward and northward components.
(The same for the real part.)

Cheers

Jonathan
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