Dear Martin and Jonathan, While going through the VolMIP names I realised I had made a mistake in some of my suggestions for this group of PMIP names. I suggested 4.3, 4.4, 4.6 and 4.7 should not be surface_net_downward_fluxes but simply surface_downward ones. If we agree on this approach they should actually say downwelling, not downward, so they would be 4.3 surface_downwelling_longwave_flux_in_air_due_to_ambient_aerosol (W m-2) 4.4 surface_downwelling_longwave_flux_in_air_due_to_dust_ambient_aerosol_assuming_clear_sky (W m-2) 4.6 surface_downwelling_shortwave_flux_in_air_due_to_ambient_aerosol (W m-2) 4.7 surface_downwelling_shortwave_flux_in_air_due_to_dust_ambient_aerosol_assuming_clear_sky (W m-2) and the definitions would need to be adjusted accordingly.
Best wishes, Alison ------ Alison Pamment Tel: +44 1235 778065 NCAS/Centre for Environmental Data Archival Email: [email protected] STFC Rutherford Appleton Laboratory R25, 2.22 Harwell Oxford, Didcot, OX11 0QX, U.K. -----Original Message----- From: CF-metadata <[email protected]> On Behalf Of Alison Pamment - UKRI STFC Sent: 14 May 2018 08:47 To: Juckes, Martin (STFC,RAL,RALSP) <[email protected]>; [email protected] Cc: Jean-Yves Peterschmitt <[email protected]> Subject: Re: [CF-metadata] PMIP: standard names for the CMIP6 data request: tws, lighning flashes, wetland emissions, etc Dear Martin and Jonathan, Thank you for proposing this set of names and for the comments received so far. The proposals look good - I have accepted a couple that seem straight forward and I think we can agree the rest quite quickly. Please have a look through my comments on the individual names and let me know what you think. > (1.1) CMIP6 short name mrtws. Terrestrial Water Storage > land_based_water_amount (kg m-2) 'The quantity with standard name > land_based_water_amount, often known as "Terrestrial Water Storage", > includes surface water (water in rivers, wetlands, lakes, snow, vegetation > and reservoirs) and subsurface water (soil moisture, groundwater).' Jonathan has suggested land_water_amount for consistency with land_ice names. I agree this is a good idea, especially if the term "land water" is already in general use. Regarding the definition, it seems we should also include at least some elements of land_ice within land_water, but there is a question as to whether this would also include floating ice shelves and/or ice sheets. This name is still under discussion. > (1.2) CMIP6 short name Flashrate. Lightning flash rate cf. > number_of_icebergs_per_unit_area; number_of_observations There are no > standard names for frequency of events, but we can adapt the "number_of_" > construction. > > Proposed name: > frequency_of_lightning_flash_per_unit_area (km-2 s-1) 'A lightning > flash is a compound event, usually consists of several discharges.' Jonathan has suggested, and Martin has agreed to, frequency_of_lightning_flashes_per_unit_area. I agree that name looks fine. I think the canonical units should probably by m-2 s-1, and I've added a sentence about frequency to the definition: frequency_of_lightning_flashes_per_unit_area (m-2 s-1) 'A lightning flash is a compound event, usually consisting of several discharges. Frequency is the number of oscillations of a wave, or the number of occurrences of an event, per unit time.' Is this okay? This name is still under discussion. 2. Wetland parameters =================== > (2.1) wetlandCH4 Grid averaged methane emissions from wetlands > surface_upward_mass_flux_of_methane_due_to_emission_from_wetland_biolo > gical_production is recently approved. In other existing names we have > "biological_processes" to cover production and consumption. The CF > area type table now includes the area type "wetland". This term is > intended to be the sum of the production term described by > surface_upward_mass_flux_of_methane_due_to_emission_from_wetland_biological_production > and a consumption term > (surface_downward_mass_flux_of_methane_due_to_emission_from_wetland_biological_consumption). > Proposed name: > surface_upward_mass_flux_of_methane_due_to_emission_from_wetland_biolo > gical_processes (kg m-2 s-1) 'The emission from biological processes is the > net emission resulting from combined production and consumption.' Usually for a net flux, we say that in the name, so this one should be: surface_net_upward_mass_flux_of_methane_due_to_emission_from_wetland_biological_processes (kg m-2 s-1) ' "Upward" indicates a vector component which is positive when directed upward (negative downward). A net upward flux is the difference between the flux from below (upward) and the flux from above (downward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The chemical formula for methane is CH4. Methane is a member of the group of hydrocarbons known as alkanes. There are standard names for the alkane group as well as for some of the individual species. 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. "Emission" means emission from a primary source located anywhere within the atmosphere, including at the lower boundary (i.e. the surface of the earth ). "Emission" is a process entirely distinct from "re-emission" which is used in some standard names. W etlands are areas where water covers the soil, or is present either at or near the surface of the soil all year or for varying periods of time during the year, including during the growing season. The precise conditions under which wetlands produce and consume methane can vary between models. The quantity with standard name surface_net_upward_mass_flux_of_methane_due_to_emission_from_wetland_biological_processes is the difference between the upward and downward surface fluxes of methane which have standard names surface_upward_mass_flux_of_methane_due_to_emission_from_wetland_biological_production and surface_downward_mass_flux_of_methane_due_to_wetland_biological_consumption, respectively.' I have adapted the sentence we usually use to describe net radiation to describe fluxes instead. We have existing standard names for both the production and consumption terms so I have added cross-references to those. The rest of the definition was constructed from existing text. Is this okay? This name is still under discussion. 3. Stratospheric optical depths > Following existing name stratosphere_mole_content_of_nitrogen_dioxide > and > atmosphere_absorption_optical_thickness_due_to_dust_ambient_aerosol_pa > rticles and > atmosphere_optical_thickness_due_to_sulfate_ambient_aerosol_particles > > (3.1) CMIP6 short name: od550aerso Stratospheric Optical depth at 550 > nm (all aerosols) 2D-field (here we limit the computation of OD to the > stratosphere only) > > Proposed name: > stratosphere_optical_thickness_due_to_ambient_aerosol_particles (1) 'The optical thickness is the integral along the path of radiation of a volume scattering/absorption/attenuation coefficient. The radiative flux is reduced by a factor exp(-"optical_thickness") on traversing the path. A coordinate variable of radiation_wavelength or radiation_frequency can be specified to indicate that the optical thickness applies at specific wavelengths or frequencies. The stratosphere optical thickness applies to radiation passing through the atmosphere layer between the tropopause and stratopause. 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. "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 hum idity 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 name and units look fine and I have constructed the definition from existing text. This name is accepted for publication in the standard name table and will be added in the May update. > (3.2) CMIP6 short name od550so4so. Stratospheric Optical depth at 550 > nm (sulphate only) 2D-field (here we limit the computation of OD to > the stratosphere only) > > Proposed name: > stratosphere_optical_thickness_due_to_sulfate_ambient_aerosol_particle > s (1) 'The optical thickness is the integral along the path of radiation of a volume scattering/absorption/attenuation coefficient. The radiative flux is reduced by a factor exp(-"optical_thickness") on traversing the path. A coordinate variable of radiation_wavelength or radiation_frequency can be specified to indicate that the optical thickness applies at specific wavelengths or frequencies. The stratosphere optical thickness applies to radiation passing through the atmosphere layer between the tropopause and stratopause. 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. "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 hum idity 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 name and units look fine and I have constructed the definition from existing text. This name is accepted for publication in the standard name table and will be added in the May update. 4. Dust >Based on >atmosphere_absorption_optical_thickness_due_to_dust_ambient_aerosol_par >ticles > > (4.1) CMIP6 short name depdust. Total Deposition Rate of Dust > > Proposed name: > surface_downward_mass_flux_of_dust_ambient_aerosol_particles (kg m-2 > s-1) It might make more sense to ask for mass flux of dry aerosols here. We have the following existing names: tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due_to_dry_deposition tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due_to_gravitational_settling tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due_to_turbulent_deposition tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due_to_wet_deposition. Dry_deposition is defined as the sum of gravitational_settling and turbulent_deposition. The sum of dry_deposition and wet_deposition is just 'deposition' which we use in some existing nitrogen_compound names. The quantity you are proposing looks to me like it should be the sum of all deposition terms and for consistency with the existing names it should be expressed as a tendency_of_atmosphere_mass_content. Putting all this together, I think the name should be written as: tendency_of_atmosphere_mass_content_of_dust_ambient_aerosol_particles_due_to_deposition (kg m-2 s-1) 'The phrase "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including "content_of_atmosphere_layer" are used. The mass is the total mass of the particles. "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 quan tity 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. "Deposition" is the sum of wet and dry deposition.' The definition was constructed from existing text. I note your comment about whether this should be a 'dry' or 'ambient' aerosol name - please see my comment on proposal 4.2 which leads me to think this one should indeed be 'ambient'. > (4.2) CMIP6 short name sedustCI. Sedimentation Flux of dust mode > coarse insoluble The adjective "coarse" has been left out of the standard > name because it appears to be implicit in the term "dust". > > Proposed name: > surface_downward_mass_flux_of_insoluble_dust_ambient_aerosol_particles > (kg m-2 s-1) The fact that this one says 'insoluble' makes me think this is what we would usually call 'dry_aerosol', i.e. it hasn't (or can't) take up water from the atmosphere. That would then suggest that proposal 4.1 is referring to ambient aerosol because it doesn't say 'insoluble'. Do others agree with that line of reasoning? We have existing names for 'coarse_mode' aerosol particles, defined as having a diameter greater than 1 micrometre, and 'nucleation_mode' aerosol particles, defined as having a diameter of less than 3 micrometres. I am not expert enough to advise on whether 'dust' would always be considered 'coarse' so I don't know whether it's necessary to include that in the name. Again we should write the name as a tendency_of_atmosphere_mass_content for consistency with existing names. This would lead us to: tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due_to_deposition (kg m-2 s-1) 'The phrase "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including "content_of_atmosphere_layer" are used. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. Aerosol particles take up ambient water (a process known as hygroscopic growth) depending on the relative humidity and the composition of the particles. "Dry aerosol particles" means aerosol particles without any water uptake. 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 quant ity named by omitting the phrase. "Deposition" is the sum of wet and dry deposition.' The definition was constructed from existing text. Writing the name this way means we then have a pair of names, 4.1 and 4.2, for deposition of ambient and dry dust aerosol particles, respectively. Are these okay? > (4.3) CMIP6 short name lwsrfasdust. All-sky Surface Longwave radiative > flux due to Dust > > Proposed name: > surface_net_downward_longwave_flux_due_to_dust_ambient_aerosol (W m-2) If this is a surface flux due to dust, does it make sense to describe it as net flux? A net downward flux would be the difference between the downwelling flux and the upwelling flux at the surface. I assume that the models don't calculate the upwelling flux due solely to dust lying on the ground(!) so I think this name should be described simply as a surface_downward flux: surface_downward_longwave_flux_due_to_ambient_aerosol (W m-2) 'The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). The term "longwave" means longwave radiation. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 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. "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 a mbient water through hygroscopic growth. The extent of hygrosc opic 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 definition was constructed from existing text. Okay? > (4.4) CMIP6 short name lwsrfcsdust. Clear-sky Surface Longwave > radiative flux due to Dust > > Proposed name: > surface_net_downward_longwave_flux_due_to_dust_ambient_aerosol_assumin > g_clear_sky (W m-2) As for proposal 4.3, I think this one should be a downward, rather than net downward, flux: surface_downward_longwave_flux_due_to_dust_ambient_aerosol_assuming_clear_sky (W m-2) 'The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). The term "longwave" means longwave radiation. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 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. "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 particl es that have taken up ambient water through hygroscopic growth. The extent of hygrosco pic 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". A phrase "assuming_condition" indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition.' Okay? > (4.5) CMIP6 short name lwtoacsdust. Clear Sky Longwave Radiative > Forcing due to Dust at TOA > > Proposed name: > toa_net_downward_longwave_flux_due_to_dust_ambient_aerosol_assuming_cl > ear_sky (W m-2) The CMIP6 description says this one is a radiative forcing, rather than a flux. Looking at existing names, I see that we have a three that include the term 'cloud_radiative_effect', e.g. toa_longwave_cloud_radiative_effect, defined as longwave cloud radiative forcing. I suggest we follow the pattern of the existing names and write this one as: toa_longwave_dust_ambient_aerosol_particles_radiative_effect (W m-2) ' "toa" means top of atmosphere. The term "longwave" means longwave radiation. Dust radiative effect is also commonly known as "dust radiative forcing". It is the difference in radiative flux resulting from the presence of dust aerosol particles, i.e. it is the difference between toa_outgoing_longwave_flux_assuming_clear_sky and toa outgoing longwave flux assuming a clear sky (i.e. no clouds) and no dust. "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 parti cles. To specify the relative humidity and temperature at which the q uantity described by the standard name applies, provide scalar coordinate variables with standard names of "relative_humidity" and "air_temperature". A phrase "assuming_condition" indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition.' Is this okay? > (4.6) CMIP6 short name swsrfasdust. All-sky Surface Shortwave > radiative flux due to Dust > >As (4.3), but for shortwave. To be consistent with 4.3, this one would be: surface_downward_shortwave_flux_due_to_ambient_aerosol (W m-2) 'The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). The term "shortwave" means shortwave radiation. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 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. "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 u p ambient water through hygroscopic growth. The extent of hygro scopic 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".' Okay? > (4.7) CMIP6 short name swsrfcsdust. Clear-sky Surface Shortwave > radiative flux due to Dust > >As (4.4), but for shortwave. To be consistent with 4.4, this one would be: surface_downward_shortwave_flux_due_to_dust_ambient_aerosol_assuming_clear_sky (W m-2) ' The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). The term "shortwave" means shortwave radiation. In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. 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. "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 pa rticles that have taken up ambient water through hygroscopic growth. The extent of hygr oscopic 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". A phrase "assuming_condition" indicates that the named quantity is the value which would obtain if all aspects of the system were unaltered except for the assumption of the circumstances specified by the condition.' Okay? Best wishes, Alison ------ Alison Pamment Tel: +44 1235 778065 NCAS/Centre for Environmental Data Archival Email: [email protected] STFC Rutherford Appleton Laboratory R25, 2.22 Harwell Oxford, Didcot, OX11 0QX, U.K. _______________________________________________ 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
