Antwort: [CF-metadata] standard name proposals

[Burkhardt.Rockel at gkss.de]

Dear Jonathan,

I agree, most people use radiative flux density. From my point of view we 
do not need to define a standard name for irradiance.  A remark in the 
info column (for e.g. surface downwelling flux density)  of the standard 
name table would be helpful.

Radiative flux is radiative energy per time (units: W). Radiative flux 
density is radiative energy per time and area (units: W m-2)

By the way I have taken the definitions from an old copy of "Terminology 
and units of radiation quantities and measurements, Radiation Commission 
of the IAMAP,  ed. E. Raschke, 1978.

Regards
Burkhardt





Jonathan Gregory <j.m.gregory at reading.ac.uk>
Gesendet von: cf-metadata-bounces at cgd.ucar.edu
26.08.2003 11:12
 
        An:     cf-metadata at cgd.ucar.edu
        Kopie: 
        Thema:  [CF-metadata] standard name proposals

Dear Burkhardt

> Irradiance is defined as "Radiant flux of any origin INCIDENT onto an 
area 
> element".
> Radiant flux density is defined as "Radiant flux of any origin  CROSSING 

> an area element".
> Both have units W m-2.

>> Is there any difference between irradiance and radiative flux density?

That's interesting. I've just received other advice from a radiation 
modeller
that irradiance and radiative flux density are really the same thing, with
irradiance being a newer, recommended, term. I agree that I have only seen
irradiance used in the context of incident flux, as you suggest.

In practice, people *do* describe an incident flux as "surface downwelling
[or downward, or total downward] flux [density]", which apparently is the
same thing as irradiance. If that is true, I think we should not define
standard names for irradiance, or alternatively define them as aliases to
standard names of radiative flux. What do you think?

Thanks. Best wishes

Jonathan
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