Hi Karl,
OK .. it looks to me as though there is some blurring between, on the one hand, the idea of an attenuation rate (the rate at which a flux we are measuring is attenuated) and, on the other hand, an attenuation coefficient (a property of a medium defined in terms of a hypothetical or reference flux). However, if that doesn't worry the people using the term, we can leave it as it is.
I've found one paper on the subject which indicates that the spectrally resolved attenuation coefficient is, to a large extent, independent of sea water properties and only depends on the spectral frequency. The spectrally averaged attenuation coefficient varies with solar zenith angle and depth because these affect the spectrum and hence the weighting of the spectral average (Lee et al, doi:10.1029/2004JC002780).
regards,
Martin
________________________________
From: CF-metadata <cf-metadata-bounces at cgd.ucar.edu> on behalf of Taylor, Karl E. <taylor13 at llnl.gov>
Sent: 24 April 2019 16:37
To: cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] Some standard name updates to improve consistency.
Hi Martin,
Regarding item 7, I'm guessing you're right that the attenuation is
wavelength specific and the downwelling shortwave has a different
spectrum that the upwelling. So I wouldn't remove "downwelling" without
some guidance from experts.
best regards,
Karl
On 4/24/19 5:41 AM, Martin Juckes - UKRI STFC wrote:
> Hello All,
>
>
> The standard name table has a high degree of internal consistency across thousands of variables, but there are a few anomalies. I'd like to suggest a few changes below. These are minor issues,
>
>
> 1. Change "aerosol" to "aerosol_particles".
>
> The overwhelming majority of aerosol terms refer to "aerosol_particles". There are two anomalies:
>
>
> * tendency_of_atmosphere_mass_content_of_sulfate_dry_aerosol_expressed_as_sulfur_due_to_wet_deposition
> * mercury_dry_aerosol
>
> Should these be changed to "aerosol_particles"?
>
> 2. Primary production vs. primary productivity
>
> There are 6 terms for net_primary_productivity_of_biomass_expressed_as_carbon..., and one for net_primary_production_of_biomass_expressed_as_carbon_per_unit_volume_in_sea_water. In addition, there are 6 terms using primary_production in the construction "due_to_net_primary_production".
>
> Production and productivity are often used interchangeably, but some people draw a distinction. E.g. using "productivity" for a rate and "production" for an amount. The usage in the standard names could be interpreted as using "primary_production" in oceanic contexts and "primary_productivity" in land contexts, but net_primary_productivity_of_biomass_expressed_as_carbon is not explicitly defined as applying only to land. Should it be?
>
> Can we either change these terms to consistently use "productivity" (or "production"), or, if that is not appropriate, provide some explanation of the use of two different terms for the same quantity?
>
> 3. aerodynamic_resistance
>
> The definition of this term implies that it refers to the aerodynamic resistance of the boundary layer, rather than the more general concept of aerodynamic resistance as defined, for example, by AMS: http://glossary.ametsoc.org/wiki/Aerodynamic_resistance .
>
> If the narrower term is intended, perhaps the name should be changed to aerodynamic_resistance_of_planetary_boundary_layer, so that it is clear that this is a boundary layer property.
>
> 4. Litter and Soil
>
> To mean the combination of litter and soil, we have one use of "soil_and_litter", one of "litter_and_soil". There are multiple uses of "vegetation_litter_and_soil", so we can take this as the preferred order.
>
> Can we change carbon_mass_flux_into_soil_and_litter_due_to_anthropogenic_land_use_or_land_cover_change to carbon_mass_flux_into_litter_and_soil_due_to_anthropogenic_land_use_or_land_cover_change for consistency?
>
>
> 5. Products
>
>
> There are 7 terms which use the old name "omega", which is now aliassed to "lagrangian_tendency_of_air_pressure". Two of these are redundant, because they are of the form "product_of_B_and_A" for terms already covered by "product_of_A_and_B".
>
> 1. product_of_specific_humidity_and_omega
> 2. product_of_omega_and_specific_humidity [redundant]
> 3. product_of_eastward_wind_and_omega
> 4. product_of_northward_wind_and_omega
> 5. product_of_air_temperature_and_omega
> 6. product_of_omega_and_air_temperature [redundant]
> 7. product_of_geopotential_height_and_omega
>
>
> Can we remove the two redundant terms, and replace "omega" with "lagrangian_tendency_of_air_pressure"?
>
>
> 6. Use of "net_downward" in aerosol indirect radiative effect terms
>
>
> There are 5 aerosol direct radiative effect terms. These are analogous to cloud radiative effect terms (3) and radiative forcing terms (12). For all the radiative forcing terms and the cloud radiative effect terms, the sign convention is assumed to be that positive forcing/radiative effect is equivalent to a downward radiative flux. This is also true for the TOA direct radiative effect term. For 4 terms describing the aerosol direct radiative effect at the surface, there is an additional inclusion of "net_downward" in the term. This looks redundant to me, and I think it should be removed for consistency with other radiative effect and forcing terms.
>
>
> * surface_net_downward_longwave_dust_ambient_aerosol_particles_direct_radiative_effect
>
> * surface_net_downward_longwave_dust_ambient_aerosol_particles_direct_radiative_effect_assuming_clear_sky
>
> * surface_net_downward_shortwave_dust_ambient_aerosol_particles_direct_radiative_effect
>
> * surface_net_downward_shortwave_dust_ambient_aerosol_particles_direct_radiative_effect_assuming_clear_sky
>
>
> 7. Use of "downwelling" in attenuation coefficients
>
> Attenuation of radiation is a measure of the reduction of strength of a radiation wave passing through a medium. It does not depend on the direction of travel of the radiation. One term includes redundant directional information:
>
> * volume_attenuation_coefficient_of_downwelling_radiative_flux_in_sea_water
>
> This term is intended have some relevance to downwelling fluxes in sea water. Possibly it is intended to be evaluated at frequencies representative of the downwelling radiative flux.
>
> Can we remove "downwelling" from this term and/or clarify any assumptions about spectral range?
>
>
> 8. Specification of air vs. ocean
>
> Scattering terms all specify whether they are in air or sea water, except one: backscattering_ratio. The definition makes it clear that this term is intended to refer to atmospheric backscattering. For consistency with other terms, it should be:
>
>
> * backscattering_ratio_in_air
>
>
> 9. cloud liquid water particle vs. particles and aerosol particle vs. particles.
>
> There are 2 terms referring to "cloud_liquid_water_particles" and 8 using the singular "cloud_liquid_water_particle". For aerosols, we have 236 referring to aerosol_particles and 2 referring to aerosol_particle.
>
> One possible distinction is between adjectival use, as in "ambient_aerosol_particle_diameter", versus the more common substantive use, as in "asymmetry_factor_of_ambient_aerosol_particles". If this approach is adopted, there are 5 aerosol particle direct radiative effect terms which should be changed to the singular adjectival form:
>
>
> * surface_net_downward_longwave_dust_ambient_aerosol_particles_direct_radiative_effect
> * surface_net_downward_longwave_dust_ambient_aerosol_particles_direct_radiative_effect_assuming_clear_sky
> * surface_net_downward_shortwave_dust_ambient_aerosol_particles_direct_radiative_effect
> * surface_net_downward_shortwave_dust_ambient_aerosol_particles_direct_radiative_effect_assuming_clear_sky
> * toa_longwave_dust_ambient_aerosol_particles_direct_radiative_effect_assuming_clear_sky
>
> The same argument would imply that all cloud liquid water particle terms should use the plural. There are two number concentration terms which already use the plural:
>
> number_concentration_of_cloud_liquid_water_particles_in_air
> number_concentration_of_cloud_liquid_water_particles_in_air_at_liquid_water_cloud_top
>
> 8 terms would need to be modified, 2 for number concentration and 6 for effective radius:
>
>
> * effective_radius_of_cloud_liquid_water_particle
> * effective_radius_of_cloud_liquid_water_particle_at_liquid_water_cloud_top
> * effective_radius_of_convective_cloud_liquid_water_particle
> * effective_radius_of_convective_cloud_liquid_water_particle_at_convective_liquid_water_cloud_top
> * effective_radius_of_stratiform_cloud_liquid_water_particle
> * effective_radius_of_stratiform_cloud_liquid_water_particle_at_stratiform_liquid_water_cloud_top
> * number_concentration_of_convective_cloud_liquid_water_particle_at_convective_liquid_water_cloud_top
> * number_concentration_of_stratiform_cloud_liquid_water_particle_at_stratiform_liquid_water_cloud_top
>
> regards,
> Martin
>
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Received on Thu Apr 25 2019 - 06:20:27 BST
