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:cf-metadata-boun...@cgd.ucar.edu] On Behalf Of > Markus Fiebig > Sent: 19 January 2016 12:49 > To: cf-metadata@cgd.ucar.edu > 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: markus.fie...@nilu.no > skype: markus.fiebig > > P Please consider the environment before printing this email and attachments _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
