Dear Maarten Thanks for your proposals.
> toa_incoming_photon_solar_irradiance_per_unit_wavelength Is "solar" necessary here? We have not included "solar" in existing stdnames referring to solar radiation. I suppose "solar" would be necessary if you specifically wanted to exclude e.g. moonshine and starlight, but is the quantity as precisely defined as that? > Note 2: Existing standard names supply aliases for these names: > "toa_incoming_spectral_photon_solar_irradiance" and > "toa_outgoing_spectral_photon_radiance" respectively. If I understand correctly, we renamed the spectral names to have the phase per_unit_wavelength. The aliases are defined for the sake of existing data. However, there is no need to introduce aliases for new standard names. Best wishes Jonathan ----- Forwarded message from Maarten Sneep <[email protected]> ----- > Date: Wed, 12 Nov 2014 18:32:34 +0100 > From: Maarten Sneep <[email protected]> > To: [email protected] > Subject: [CF-metadata] Proposal for standard names: radiance and irradiance as > measured from satellite > User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 > Thunderbird/24.7.0 > > Hi all, > > I hereby propose the addition of the following standard names. All > are commonly used quantities used in passive satellite remote > sensing, to be specific instruments that use ultra-violet, visible > and near infra-red radiation for remote sensing of atmospheric > composition, sometimes including wavelengths up to 2.5 micrometer > (shortwave radiation). > > Examples of these instruments include GOME, SCIAMACHY, OMI, GOME-2, > OMPS, and the upcoming TROPOMI on Sentinel 5 precursor, and > instruments on Sentinel 4 and Sentinel 5 missions. > > Please note the notes at the end. > > ------------------------------------------------------------------------- > * toa_incoming_photon_solar_irradiance_per_unit_wavelength > > "toa" means top of atmosphere. "Photon solar irradiance" is the > photon flux on a surface perpendicular to the incoming solar > radiation. The direction is specified as "incoming". A photon flux > is specified in terms of numbers of photons expressed in moles. The > "per unit wavelength" indicates a spectrally resolved quantity. A > coordinate variable for radiation wavelength should be given the > standard name radiation_wavelength. > > Canonical unit: mol m-2 m-1 s-1 > > ------------------------------------------------------------------------- > * toa_outgoing_photon_radiance_per_unit_wavelength > > "toa" means top of atmosphere. "Photon radiance" is the photon flux > in a particular direction, per unit of solid angle. The direction is > specified as "outgoing", i.e. radiation from below. A photon flux is > specified in terms of numbers of photons expressed in moles. The > "per unit wavelength" indicates a spectrally resolved quantity. A > coordinate variable for radiation wavelength should be given the > standard name radiation_wavelength. > > Canonical unit: mol m-2 m-1 s-1 sr-1 > > ------------------------------------------------------------------------- > Note 1: The coordinate variable for radiation wavelength may require > a mapping that is similar to the mapping of geolocation coordinates > for satellite observations, i.e. not a dimension, but a multi > dimensional mapping. This is the case for the OMI instrument, where > a 2D-dectector is used for wavelength (columns of CCD) and a spatial > dimension across the swath (rows of CCD). The mapping is imperfect, > and the wavelength depends on the row-index. > > Note 2: Existing standard names supply aliases for these names: > "toa_incoming_spectral_photon_solar_irradiance" and > "toa_outgoing_spectral_photon_radiance" respectively. > > Note 3: mole as a unit for counting photons is unconventional within > the satellite community, photon fluxes are typically expressed in > 'photons cm-2 nm-1 s-1' and 'photons cm-2 nm-1 s-1 sr-1'. It would > be nice to add 'photon' as an alias to UDUnits, in a way that is > similar to the recent addition of 'molecule'. > > Note 4: Other instruments may use other units, depending on the > construction of the instrument. These can not be converted easily > into one another as they require additional knowledge, in particular > knowledge of the wavelength. I'm unsure if UDUnits is equiped to > handle these types of conversion. Additional names may be needed for > using "W m-2 m-1" or "W m-2 m-1 sr-1" respectively (similar name, > but leaving out the 'photon') Another quantity that is commonly > encountered expresses the radiation_wavelength as wavenumber or > frequency, and therefore also alters the (frequency/energy) interval > over which the quantity is integrated. I'll leave the addition of > these quantities to communities that actually use them, IASI on > MetOp comes to mind. > > Kind regards, > > Maarten Sneep > -- > KNMI > E: [email protected] > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
