Dear Andreas, Thank you. The name is accepted and will be included in the next standard name table update.
Best wishes, Alison ------ Alison Pamment Tel: +44 1235 778065 Centre for Environmental Data Analysis Email: [email protected] STFC Rutherford Appleton Laboratory R25, 2.22 Harwell Campus, Didcot, OX11 0QX, U.K. > -----Original Message----- > From: Bodas-Salcedo, Alejandro > [mailto:[email protected]] > Sent: 03 March 2016 10:37 > To: Pamment, Alison (STFC,RAL,RALSP); [email protected] > Subject: RE: [CF-metadata] New standard name for aerosol single scattering > albedo > > Dear Alison, > > Thanks for looking into this. I am happy with the name and definition. > > Regards, > > Alejandro > > > > -----Original Message----- > > From: [email protected] [mailto:[email protected]] > > Sent: 02 March 2016 17:40 > > To: Bodas-Salcedo, Alejandro; [email protected] > > Subject: RE: [CF-metadata] New standard name for aerosol single > scattering albedo > > > > Dear Alejandro and Markus, > > > > Just picking up on Alejandro's proposal. I like the suggestion of > > single_scattering_albedo_in_air_due_to_ambient_aerosol_particles > (canonical > > units:1 (dimensionless)). > > This is indeed consistent with the syntax of existing names. The > > "due_to_ambient_aersol_particles" phrase should be understood to mean > that the > > scattering is indeed due to the particulate component of the aerosol and > not the > > surrounding air. We have standard definition text that should make all > that clear: > > ' "Single scattering albedo" is the fraction of radiation in an incident > > light > beam > > scattered by the particles of an aerosol reference volume for a given > wavelength. It > > is the ratio of the scattering and the extinction coefficients of the > > aerosol > particles in > > the reference volume. A coordinate variable with a standard name of > > radiation_wavelength or radiation_frequency should be included to > specify either the > > wavelength or frequency. "Aerosol" means the system of suspended > liquid or solid > > particles in air (except cloud droplets) and their carrier gas, the air > > itself. > > "Ambient_aerosol" means that the aerosol is measured or modelled at the > ambient > > state of pressure, temperature and relative humidity that exists in its > immediate > > environment. "Ambient aerosol particles" are aerosol particles that have > taken up > > ambient water through hygroscopic growth. The extent of hygroscopic > growth > > depends on the relative humidity and the composition of the particles. To > specify the > > relative humidity and temperature at which the quantity described by the > standard > > name applies, provide scalar coordinate variables with standard names of > > "relative_humidity" and "air_temperature". The specification of a physical > process > > by the phrase "due_to_" process means that the quantity named is a single > term in a > > sum of terms which together compose the general quantity named by > omitting the > > phrase.' > > > > Alejandro, if you are happy with this then I think the name can be > accepted for > > inclusion in the standard name table. > > > > Best wishes, > > Alison > > > > ------ > > Alison Pamment Tel: > > +44 1235 778065 > > Centre for Environmental Data Analysis Email: > [email protected] > > STFC Rutherford Appleton Laboratory > > R25, 2.22 > > Harwell Campus, Didcot, OX11 0QX, U.K. > > > > > > > > > -----Original Message----- > > > From: CF-metadata [mailto:[email protected]] On > Behalf > > > Of Bodas-Salcedo, Alejandro > > > Sent: 20 January 2016 09:37 > > > To: [email protected] > > > Subject: Re: [CF-metadata] New standard name for aerosol single > scattering > > > albedo > > > > > > Dear Markus, > > > > > > Thanks for your comment. I'm happy with the change to a population of > > > particles. As you say, it's a more practical definition. I find the first > sentence > > > a bit difficult, though. What about the following? > > > > > > > > > Definition: Fraction of radiation in an incident light beam scattered by > the > > > particles of an aerosol reference volume as a function of wavelength. It > is > > > the ratio of the scattering and the extinction coefficients of the > > > aerosol > > > particles in the reference volume. A coordinate of radiation_wavelength > or > > > radiation_frequency should be included to specify either the > wavelength or > > > frequency. > > > > > > Regarding the humidity state, perhaps we should follow the definition > for > > > the extinction coefficient, and use the name > > > > > > single_scattering_albedo_in_air_due_to_ambient_aerosol_particles > > > > > > My only reservation is that this seems to refer to the optical properties > of > > > aerosols plus the molecular atmosphere, not only aerosols. > > > > > > Regards, > > > > > > Alejandro > > > > > > > > > > -----Original Message----- > > > > From: CF-metadata [mailto:[email protected]] On > > > Behalf Of > > > > Markus Fiebig > > > > Sent: 19 January 2016 12:49 > > > > To: [email protected] > > > > Subject: Re: [CF-metadata] New standard name for aerosol single > > > scattering albedo > > > > > > > > Dear Alejandro, > > > > > > > > after reading your mail, I was surprised to realise that > > > > aerosol_single_scattering_albedo in fact hadn't been defined yet. > > > > > > > > However, the definition you propose seems to me rather unusual. You > > > define the > > > > single scattering albedo with respect to a single particle as ratio of > > > > cross-sections, i.e. as truly microscale property. From the multitude of > > > > particles contained in an aerosol, how do you determine which particle > > > you refer to? > > > > > > > > From my experience, it's more usual to define the single scattering > albedo > > > as > > > > ratio of scattering and extinction coefficient of a particle population, > i.e. > > > an > > > > effective property for the ensemble of particles contained in the > aerosol. > > > How > > > > about this: > > > > > > > > Definition: Fraction of radiation in an incident light beam interacting > with > > > the > > > > particles of an aerosol reference volume and scattered by these > particles > > > as a > > > > function of wavelength. It is the ratio of the scattering and the > extinction > > > > coefficients of the aerosol particles in the reference volume. A > coordinate > > > of > > > > radiation_wavelength or radiation_frequency should be included to > > > specify either > > > > the wavelength or frequency. > > > > > > > > Having said that, should we also consider to include the humidity state > of > > > the > > > > aerosol? That would require relative_humidity as additional coordinate > > > variable. > > > > > > > > Best regards, > > > > Markus > > > > > > > > Am 19.01.2016 um 10:47 schrieb Bodas-Salcedo, Alejandro: > > > > > Dear All, > > > > > > > > > > I'd like to propose a new standard name, which as far as I can see > doesn't > > > > currently exist in the CF table: > > > > > > > > > > Name: aerosol_single_scattering_albedo > > > > > Units: 1 > > > > > Description: Fraction of radiation scattered out of a pencil of > > > > > radiation > > > after one > > > > encounter with an aerosol particle for a given wavelength. It is the > ratio > > > between the > > > > scattering cross-section and the extinction cross-section. A coordinate > of > > > > radiation_wavelength or radiation_frequency should be included to > > > specify either the > > > > wavelength or frequency. > > > > > > > > > > > > > > > Thanks, > > > > > > > > > > Alejandro > > > > > > > > > > > > > -- > > > > Dr. Markus Fiebig > > > > Senior Scientist > > > > Dept. Atmospheric and Climate Research (ATMOS) > > > > Norwegian Institute for Air Research (NILU) > > > > P.O. Box 100 > > > > N-2027 Kjeller > > > > Norway > > > > > > > > Tel.: +47 6389-8235 > > > > Fax : +47 6389-8050 > > > > e-mail: [email protected] > > > > skype: markus.fiebig > > > > > > > > P Please consider the environment before printing this email and > > > attachments > > > _______________________________________________ > > > CF-metadata mailing list > > > [email protected] > > > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
