Martin,

this is a bit more complicated

the radiative fluxes used in climate studies are usually spectrally
integrated and usually for these bradband fluxes there is a distinction
between solar broadband and IR broadband fluxes.

now for these broadband fluxes we also like to distinguish between
clear-sky and all-sky fluxes and for the clear-sky downward fluxes
there is a difference if these are based on observations under clear-sky
conditions or if they are based on simulations where clouds were simply
removed (but not the higher water vapor compared to clear-sky)

I would look if there are some definitions for radiative fluxes in the
radiation or climate section ...?

Stefan


On 2/18/2011 2:27 PM, Schultz, Martin wrote:
Dear colleagues,

     I am trying to clean up some data files and make them CF compliant. But I 
am confused about the standard name that I could use for (measured) 
irradiation. There is an entry

"downwelling_spectral_radiative_flux_in_air
Downwelling radiation is radiation from above. It does not mean "net downward". "spectral" means per unit wavelength or as a function 
of wavelength; spectral quantities are sometimes called "monochromatic". Radiation wavelength has standard name radiation_wavelength. When 
thought of as being incident on a surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity 
measured by a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical disciplines, 
"flux" implies per unit area, called "flux density" in physics."

     This definition explicitly mentions "irradiance", so I guess I am close to the solution. However, the irradiance 
measurement data I have are not "spectral". I did not find a standard_name entry 
"downwelling_radiative_flux_in_air" which I would have expected to be the integral flux. There are only various 
variants of "surface_net..." or "surface_spectral..." fluxes. These don't help, or am I wrong here?

     Unless I am mistaken or have overlooked something obvious, I therefore 
propose to add a standard_name tabel entry:

"downwelling_radiative_flux_in_air
Downwelling radiation is radiation from above. It does not mean "net downward". When thought of as being incident on a 
surface, a radiative flux is sometimes called "irradiance". In addition, it is identical with the quantity measured by 
a cosine-collector light-meter and sometimes called "vector irradiance". In accordance with common usage in geophysical 
disciplines, "flux" implies per unit area, called "flux density" in physics. For spectrally resolved 
radiative flux or net radiative flux see downwelling_spectral_radiative_flux_in_air
or surface_net_downward_radiative_flux, respectively."


Best regards,

Martin Schultz

= Dr. Martin G. Schultz, IEK-8, Forschungszentrum Jülich  =
= D-52425 Jülich, Germany                                 =
= ph: +49 (0)2461 61 2831, fax: +49 (0)2461 61 8131       =
= email: m.schu...@fz-juelich.de                          =
= web: http://www.fz-juelich.de/icg/icg-2/m_schultz       =

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--
Stefan Kinne
MPI-Meteorology
Bundesstrasse 53
20146 Hamburg
stefan.ki...@zmaw.de
tel +49 40 41173 383
fax +49 40 41173 298

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