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 <maarten.sneep at knmi.nl> -----
> Date: Wed, 12 Nov 2014 18:32:34 +0100
> From: Maarten Sneep <maarten.sneep at knmi.nl>
> To: cf-metadata at cgd.ucar.edu
> 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: maarten.sneep at knmi.nl
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----- End forwarded message -----
Received on Mon Nov 17 2014 - 09:23:18 GMT
