Hi everybody,
after a good while and a new round of iterations, I'd like to come back to a previously proposed set of new standard names for atmospheric aerosol properties that are commonly measured in ground stations around the globe. The list has been somewhat modified and amended as compared to my last proposal. A common characteristic of these standard names is that they are to be used not only in NetCDF-CF files, but also in data discovery portals, i.e. independent from a file. They therefore contain some details that could be deduced by looking at the file itself, but will be of great help in describing the content of a file without looking at it. One such example is the use of the prefix "surface_" as described on the CF standard names syntax webpage, where it says that this prefix describes a property at the lower boundary of the atmosphere.
Another specialty of the proposed names is the use of the phrase "_due_to_dried_aerosol". Ground stations in the WMO GAW network are supposed to measure the aerosol properties at dry state (RH < 40%), but especially in the tropics, it may be impossible to reach this target RH and the drying may be incomplete. Using such a standard name in a file requires a co-ordinate variable "relative_humidity".
The set of proposed standard names also contains 2 auxiliary variables to be used as coordinates for other standard names (see end of list).
I'm curious for your comments.
Best regards,
Markus
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Draft CF standard names for surface aerosol optical properties (2013-10-11)
1) volume_scattering_coefficient_in_air_due_to_ambient_aerosol
The volume scattering coefficient is the fractional change of radiative flux per unit path length due to redirection of an incident light beam by a component in the reference volume. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Ambient_aerosol" means that the aerosol sample is measured at its ambient state of pressure, temperature, and relative humidity. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths or frequencies.
2) surface_volume_scattering_coefficient_in_air_due_to_ambient_aerosol
The volume scattering coefficient is the fractional change of radiative flux per unit path length due to redirection of an incident light beam by a component in the reference volume. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Ambient_aerosol" means that the aerosol sample is measured at its ambient state of pressure, temperature, and relative humidity. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. "surface" means that the property applies at the lower boundary of the atmosphere. A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths or frequencies.
3) volume_scattering_coefficient_in_air_due_to_dried_aerosol
The volume scattering coefficient is the fractional change of radiative flux per unit path length due to redirection of an incident light beam by a component in the reference volume. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Dried_aerosol" means that the aerosol sample has been dried from the ambient state, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths or frequencies.
4) volume_absorption_coefficient_in_air_due_to_dried_aerosol
The volume absorption coefficient is the fractional change of radiative flux per unit path length due to absorption of an incident light beam by a component in the reference volume. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Dried_aerosol" means that the aerosol sample has been dried from the ambient state, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths or frequencies.
5) volume_spherical_backscattering_coefficient_in_air_due_to_dried_aerosol
The volume spherical backscattering coefficient is the fractional change of radiative flux per unit path length due to redirection of an incident light beam into the rearward hemisphere relative to the incident beam by a component in the reference volume. It is distinct from the backscattering coefficient which isn't integrated over the rearward hemisphere. "Dried_aerosol" means that the aerosol sample has been dried from the ambient state, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths
or frequencies.
6) surface_volume_scattering_coefficient_at_stp_in_air_due_to_pm1_dried_aerosol
The volume scattering coefficient is the fractional change of radiative flux per unit path length due to redirection of an incident light beam by a component in the reference volume. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Dried_aerosol" means that the aerosol sample has been dried from the ambient state, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. "surface" means that the property applies at the lower boundary of the atmosphere. "at_stp" refers to a volume at standard conditions of temperature (273.15 K) and pressure (1013.25 hPa). "pm1" refers to the fraction of aerosol particles with
an aerodynamic diameter of less than or equal to 1 micrometer, where the size cut is applied under ambient conditions before aerosol humidity, pressure, or temperature are possibly altered. To specify the relative humidity at which the sample was sized, provide scalar coordinate variable with the standard name of "sizing_relative_humidity".A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths or frequencies.
7) surface_volume_scattering_coefficient_at_stp_in_air_due_to_pm2p5_dried_aerosol
The volume scattering coefficient is the fractional change of radiative flux per unit path length due to redirection of an incident light beam by a component in the reference volume. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Dried_aerosol" means that the aerosol sample has been dried from the ambient state, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. "surface" means that the property applies at the lower boundary of the atmosphere. "at_stp" refers to a volume at standard conditions of temperature (273.15 K) and pressure (1013.25 hPa). "pm2p5" refers to the fraction of aerosol particles wit
h an aerodynamic diameter of less than or equal to 2.5 micrometer, where the size cut is applied under ambient conditions before aerosol humidity, pressure, or temperature are possibly altered. To specify the relative humidity at which the sample was sized, provide scalar coordinate variable with the standard name of "sizing_relative_humidity". A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths or frequencies.
8) surface_volume_scattering_coefficient_at_stp_in_air_due_to_pm10_dried_aerosol
The volume scattering coefficient is the fractional change of radiative flux per unit path length due to redirection of an incident light beam by a component in the reference volume. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Dried_aerosol" means that the aerosol sample has been dried from the ambient state, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. "surface" means that the property applies at the lower boundary of the atmosphere. "at_stp" refers to a volume at standard conditions of temperature (273.15 K) and pressure (1013.25 hPa). "pm10" refers to the fraction of aerosol particles wit
h an aerodynamic diameter of less than or equal to 10 micrometers, where the size cut is applied under ambient conditions before aerosol humidity, pressure, or temperature are possibly altered. To specify the relative humidity at which the sample was sized, provide scalar coordinate variable with the standard name of "sizing_relative_humidity". A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths or frequencies.
9) surface_volume_absorption_coefficient_at_stp_in_air_due_to_pm1_dried_aerosol
The volume absorption coefficient is the fractional change of radiative flux per unit path length due to absorption of an incident light beam by a component in the reference volume. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Dried_aerosol" means that the aerosol sample has been dried from the ambient state, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. "surface" means that the property applies at the lower boundary of the atmosphere. "at_stp" refers to a volume at standard conditions of temperature (273.15 K) and pressure (1013.25 hPa). "pm1" refers to the fraction of aerosol particles with a
n aerodynamic diameter of less than or equal to 1 micrometers, where the size cut is applied under ambient conditions before aerosol humidity, pressure, or temperature are possibly altered. To specify the relative humidity at which the sample was sized, provide scalar coordinate variable with the standard name of "sizing_relative_humidity". A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths or frequencies.
10) surface_volume_absorption_coefficient_at_stp_in_air_due_to_pm2p5_dried_aerosol
The volume absorption coefficient is the fractional change of radiative flux per unit path length due to absorption of an incident light beam by a component in the reference volume. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Dried_aerosol" means that the aerosol sample has been dried from the ambient state, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. "surface" means that the property applies at the lower boundary of the atmosphere. "at_stp" refers to a volume at standard conditions of temperature (273.15 K) and pressure (1013.25 hPa). "pm2p5" refers to the fraction of aerosol particles with
an aerodynamic diameter of less than or equal to 2.5 micrometers, where the size cut is applied under ambient conditions before aerosol humidity, pressure, or temperature are possibly altered. To specify the relative humidity at which the sample was sized, provide scalar coordinate variable with the standard name of "sizing_relative_humidity". A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths or frequencies.
11) surface_volume_absorption_coefficient_at_stp_in_air_due_to_pm10_dried_aerosol
The volume absorption coefficient is the fractional change of radiative flux per unit path length due to absorption of an incident light beam by a component in the reference volume. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Dried_aerosol" means that the aerosol sample has been dried from the ambient state, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. "surface" means that the property applies at the lower boundary of the atmosphere. "at_stp" refers to a volume at standard conditions of temperature (273.15 K) and pressure (1013.25 hPa). "pm10" refers to the fraction of aerosol particles with
an aerodynamic diameter of less than or equal to 10 micrometers, where the size cut is applied under ambient conditions before aerosol humidity, pressure, or temperature are possibly altered. To specify the relative humidity at which the sample was sized, provide scalar coordinate variable with the standard name of "sizing_relative_humidity". A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths or frequencies.
12) surface_volume_spherical_backscattering_coefficient_at_stp_in_air_due_to_pm1_dried_aerosol
The volume spherical backscattering coefficient is the fractional change of radiative flux per unit path length due to redirection of an incident light beam into the rearward hemisphere relative to the incident beam by a component in the reference volume. It is distinct from the backscattering coefficient which isn't integrated over the rearward hemisphere. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Dried_aerosol" means that the aerosol sample has been dried from the ambient state, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. "surface" means that the property applies at the lower boundary of
the atmosphere. "at_stp" refers to a volume at standard conditions of temperature (273.15 K) and pressure (1013.25 hPa). "pm1" refers to the fraction of aerosol particles with an aerodynamic diameter of less than or equal to 1 micrometers, where the size cut is applied under ambient conditions before aerosol humidity, pressure, or temperature are possibly altered. To specify the relative humidity at which the sample was sized, provide scalar coordinate variable with the standard name of "sizing_relative_humidity". A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths or frequencies.
13) surface_volume_spherical_backscattering_coefficient_at_stp_in_air_due_to_pm2p5_dried_aerosol
The volume spherical backscattering coefficient is the fractional change of radiative flux per unit path length due to redirection of an incident light beam into the rearward hemisphere relative to the incident beam by a component in the reference volume. It is distinct from the backscattering coefficient which isn't integrated over the rearward hemisphere. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Dried_aerosol" means that the aerosol sample has been dried from the ambient state, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. "surface" means that the property applies at the lower boundary of
the atmosphere. "at_stp" refers to a volume at standard conditions of temperature (273.15 K) and pressure (1013.25 hPa). "pm2p5" refers to the fraction of aerosol particles with an aerodynamic diameter of less than or equal to 2.5 micrometers, where the size cut is applied under ambient conditions before aerosol humidity, pressure, or temperature are possibly altered. To specify the relative humidity at which the sample was sized, provide scalar coordinate variable with the standard name of "sizing_relative_humidity". A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths or frequencies.
14) surface_volume_spherical_backscattering_coefficient_at_stp_in_air_due_to_pm10_dried_aerosol
The volume spherical backscattering coefficient is the fractional change of radiative flux per unit path length due to redirection of an incident light beam into the rearward hemisphere relative to the incident beam by a component in the reference volume. It is distinct from the backscattering coefficient which isn't integrated over the rearward hemisphere. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Dried_aerosol" means that the aerosol sample has been dried from the ambient state, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". 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. "surface" means that the property applies at the lower boundary of
the atmosphere. "at_stp" refers to a volume at standard conditions of temperature (273.15 K) and pressure (1013.25 hPa). "pm10" refers to the fraction of aerosol particles with an aerodynamic diameter of less than or equal to 10 micrometers, where the size cut is applied under ambient conditions before aerosol humidity, pressure, or temperature are possibly altered. To specify the relative humidity at which the sample was sized, provide scalar coordinate variable with the standard name of "sizing_relative_humidity". A coordinate variable of radiation_wavelength or radiation_frequency needs to be specified to indicate that the property applies at specific wavelengths or frequencies.
15)surface_particle_number_concentration_at_stp_in_aerosol
The particle number concentration is the total number of aerosol particles per unit volume independent of and integrated over particle size. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "surface" means that the property applies at the lower boundary of the atmosphere. "at_stp" refers to a volume at standard conditions of temperature (273.15 K) and pressure (1013.25 hPa).
16)surface_particle_number_size_distribution_at_stp_in_dried_aerosol
The particle number size distribution is the number concentration of aerosol particles per decadal logarithmic size interval as a function of particle diameter. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Dried_aerosol" means that the aerosol sample has been dried from the ambient state, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the property applies, provide scalar coordinate variable with the standard name of "relative_humidity". "surface" means that the property applies at the lower boundary of the atmosphere. "at_stp" refers to a volume at standard conditions of temperature (273.15 K) and pressure (1013.25 hPa). A coordinate variable of "electrical_mobility_particle_diameter" needs to be specified to indicate that the property applies at specific particle sizes.
17)surface_cloud_condensation_nuclei_number_concentration_at_stp_in_aerosol
The cloud condensation nuclei number concentration is the total number of aerosol particles per unit volume independent of and integrated over particle size that act as condensation nuclei for liquid-phase clouds. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "surface" means that the property applies at the lower boundary of the atmosphere. "at_stp" refers to a volume at standard conditions of temperature (273.15 K) and pressure (1013.25 hPa). A coordinate variable of "relative_humidity" needs to be specified to indicate that the property refers to a specific supersaturations with respect to liquid water.
18)surface_cloud_condensation_nuclei_number_size_distribution_at_stp_in_dried_aerosol
The cloud condensation nuclei number size distribution is the number concentration of aerosol particles per decadal logarithmic size interval as a function of particle diameter that act as condensation nuclei for liquid-phase clouds. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). "Dried_aerosol" means that the aerosol sample has been dried from the ambient state before sizing, but that the dry state (RH < 40%) hasn't necessarily been reached. To specify the relative humidity at which the sample was sized, provide scalar coordinate variable with the standard name of "sizing_relative_humidity". "surface" means that the property applies at the lower boundary of the atmosphere. "at_stp" refers to a volume at standard conditions of temperature (273.15 K) and pressure (1013.25 hPa). Coordinate variables of "electrical_mobility_particle_diameter" and "relative_humidity" need to be specified to indicate that the property refers to specific particle sizes and supersaturations
with respect to liquid water.
19)electrical_mobility_particle_diameter
Refers to the diameter of an aerosol particle as selected by its electrical mobility.
20)sizing_relative_humidity
Relative humidity at which the size of an aerosol particle was selected.
_______________________________________
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.Fiebig at nilu.no
skype: markus.fiebig
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