[CF-metadata] Proposal for new standard names

From: Jonathan Gregory <j.m.gregory>
Date: Wed, 11 Feb 2009 19:20:28 +0000

Dear Alejandro

> height_of_full_levels_above_reference_ellipsoid [m]
> height_of_half_levels_above_reference_ellipsoid [m]
standard names do not indicate coordinate variables, so the standard name for
these is height_above_reference_ellipsoid, which is already in the table, and
the variable should have a vertical coordinate variable of model_level_number.

> air_pressure_at_full_levels [Pa]
> air_pressure_at_half_levels [Pa]
Likewise. The standard name is air_pressure.

> b) Cloud condensate mixing ratios [1]
> mixing_ratio_large_scale_cloud_liquid
> mixing_ratio_large_scale_cloud_ice
> mixing_ratio_convective_cloud_liquid
> mixing_ratio_convective_cloud_ice
> mixing_ratio_of_ozone_in_air [1]
Are these the same as
  mass_fraction_of_stratiform_cloud_liquid_water_in_air
  mass_fraction_of_stratiform_cloud_ice_in_air
  mass_fraction_of_convective_cloud_liquid_water_in_air
  mass_fraction_of_convective_cloud_ice_in_air
  mass_fraction_of_ozone_in_air
which are in the table, or are you intending to draw a precise distinction
between mixing_ratio and mass_fraction? There have been lengthy discussions on
the email list with the outcome that a distinction is not made except for the
case of water vapour in air.

> d) Radiative properties of clouds. Optical depths at 0.67 micron and
> emissivities at 10.5 micron.
The wavelengths should be specified with a scalar coordinate variable
of radiation_wavelength.

> large_scale_cloud_optical_depth [1]
> convective_cloud_optical_depth [1]
For consistency with the existing optical depth standard names, I suggest
these should be
  atmosphere_optical_thickness_due_to_large_scale|convective_cloud

> large_scale_cloud_emissivity [1]
> convective_cloud_emissivity [1]
If the variable does specify the wavelength, I think it is OK just to say
emissivity. Young-In Wong has recently proposed surface_longwave_emissivity,
which does not specify a precise wavelength.

> e) Surface variables. Emissivity at 10.5 micron.
> skin_temperature [K]
The variable called surface_temperature is the temperature at the interface.
Is that what you mean?

> h) Cloud fractions from CALIPSO/CLOUDSAT simulators. Units: 1.
> calipso_total_cloud_fraction
Should be calipso_cloud_area_fraction like isccp_cloud_area_fraction
(but see also below).

> calipso_low_level_cloud_fraction
> calipso_mid_level_cloud_fraction
> calipso_high_level_cloud_fraction
I'd say low, mid and high are coordinates. They should be specified as
coordinate variables, rather than in the standard name. We have not so far
named cloud layers in this way.

> calipso_cloud_fraction
> calipsonocloudsat_cloud_fraction
> calipso_and_cloudsat_total_cloud_fraction
I'm not sure what these mean.

> i.1 CloudSat Radar Reflectivity Factor (94 GHz)
> cloudsat_radar_reflectivity_94 [dBZ]
The frequency should be specified as a scalar coordinate variable of
radiation_frequency, which is not in the table at present but could be
proposed. The name can then be just cloudsat_radar_reflectivity. Is it
necessary to name "cloudsat" in this? I tend to think it would be better to
be more generic i.e. just radar_reflectivity.

> i.2 CALIPSO Lidar Attenuated Total Backscatter (532 nm)
> calipso_atb_532 [1]
Again, the wavelength is a coordinate and should not be in the name. Could
"total" be omitted? Usually we assume that unqualified concepts are inclusive.
Thus
  lidar_attenuated_backscatter
But I'm not familiar with this so I don't know what the relationship is between
this quantity and the next one
> calipso_molecular_backscatter_532 [m-1 sr-1]
Perhaps you or someone else could clarify. As they don't have the same units
the names should distinguish them more. Are they analogous to these quantities
in the table?
  surface_backwards_scattering_coefficient_of_radar_wave: 1
  volume_backwards_scattering_coefficient_of_radiative_flux_in_sea_water:m-1
  volume_scattering_coefficient_of_radiative_flux_in_sea_water:m-1
  volume_scattering_function_of_radiative_flux_in_sea_water:m-1 sr-1
If so, similar names should be adopted.

> k) Outputs from ISCCP simulator. Units are [1] otherwise stated.
> isccp_total_cloud_area_fraction
We already have
  isccp_cloud_area_fraction
> isccp_mean_cloud_albedo
Could this be simply
  cloud_albedo
> isccp_mean_cloud_top_pressure [Pa]
  air_pressure_at_cloud_top
is already in the table.
> isccp_mean_brightness_temperature_assuming_clear_sky [K]
> isccp_mean_brightness_temperature [K]
> isccp_mean_optical_depth
With these variables, is isccp necessary? Standard names are intended to
name geophysical quantities. If ISCCP is estimating geophysical quantities,
they do not need isccp in their names. For instance, we don't have a quantity
called hadisst_sea_surface_temperature. The quantity is just SST, and HadISST
is one estimate of it. ISCCP could be identified in one of the global
attributes of the file. I am not sure why we included a standard name for
ISCCP cloud area fraction and whether we should do so for CALIPSO or this one
> misr_cloud_area_fraction
>
> m) PARASOL-like mono-directional reflectance. Units: 1.
> parasol_reflectance
Could you explain what that means?

Best wishes

Jonathan
Received on Wed Feb 11 2009 - 12:20:28 GMT