Dear Jonathan,
> > tendency_of_mass_fraction_of_stratiform_cloud_liquid_water_in_air_due_convective_detrainment (s-1)
> > tendency_of_mass_fraction_of_stratiform_cloud_ice_in_air_due_convective_detrainment (s-1)
>
> I think these are OK, except for to_ being needed after due_
ok.
Then that gives:
tendency_of_mass_fraction_of_stratiform_cloud_liquid_water_in_air_due_to_convective_detrainment (s-1)
tendency_of_mass_fraction_of_stratiform_cloud_ice_in_air_due_to_convective_detrainment (s-1)
> > 2/ I would like to propose aliases for the following variables:
> > tendency_of_air_temperature_due_to_stratiform_cloud_condensation_and_evaporation
> > tendency_of_specific_humidity_due_to_stratiform_cloud_condensation_and_evaporation
>
> Also OK. I agree with your argument. It is a pity there's isn't a single word
> for condensation_and_evaporation! There are other large-scale precipitation
> names in the standard name table, but I assume these are not affected by your
> argument, as they are not specifically about phase change. Do you agree?
Yes.
> > 3/ New eddy diffusivity variables:
> >
> > eddy_viscosity_coefficients_for_momentum_variables (m2 s-1)
> > eddy_diffusivity_coefficients_for_temperature_variable (m2 s-1)
> > eddy_diffusivity_coefficients_for_water_variables (m2 s-1)
>
> I suggest that the existing names
> atmosphere_heat_diffusivity:m2 s-1
> atmosphere_momentum_diffusivity:m2 s-1
> have the meaning you intend for the first two of these.
Agreed.
> For the third one we
> could introduce an analogous
> atmosphere_moisture_diffusivity:m2 s-1
> for humidity. But perhaps you have a broader class of quantities in mind?
Following discussion with Adrian Lock and Joao Teixeira we have decided
that this variable is not necessary. ( For most models the same diffusivity
will be applied to temperature and humidity variables, and where they
are different the difference is probably not something we would want
to analyse. )
We will withdraw it from the CMIP5 list and so are no longer proposing its
addition to the standard names list.
> > 4/ Atmospheric convective mass fluxes
>
> The definition of atmosphere_convective_mass_flux indicates that cell_methods
> should specify what area is in the denominator. If cell_methods says
> "mean where cloud", the quantity is integral of the convective mass flux over
> the cloud area, divided by the cloud area. For the integral over the cloud
> area, divided by the whole grid cell, cell_methods says "mean where cloud
> over all_area_types". This kind of distinction is not made in standard names.
> (See http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.4/cf-conventions.html#cell-methods)
> I think that is a different issue from your need to introduce distinctions
> which are really process-related, and hence require different standard names.
Yes, I see. We will retain the cell method specification in the CMIP5
table information, but it doesn't need to be in the standard name
definition.
> In CF standard names, we use American spelling, and the AMS glossary has
> "draft" but not "draught", so I think we ought to follow that (a triumph of
> phonetics over etymology). Hence I would agree with
>
> > atmosphere_updraft_convective_mass_flux kg m-2 s-1
> > atmosphere_downdraft_convective_mass_flux kg m-2 s-1
> > atmosphere_shallow_convective_mass_flux kg m-2 s-1
> > atmosphere_deep_convective_mass_flux kg m-2 s-1
>
> but the definitions need not specify how the averaging is done.
ok.
Thanks. A revised summary of my proposed changes follows.
Mark
1/ Additional cloud condensate tendencies (see
http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2009/002730.html )
tendency_of_mass_fraction_of_stratiform_cloud_liquid_water_in_air_due_to_convective_detrainment (s-1)
tendency_of_mass_fraction_of_stratiform_cloud_ice_in_air_due_to_convective_detrainment (s-1)
2/ I would like to propose aliases for the following variables:
tendency_of_air_temperature_due_to_large_scale_precipitation
to have a new alias
tendency_of_air_temperature_due_to_stratiform_cloud_condensation_and_evaporation
The 'stratiform' makes this more consistent with other cloud variables already
agreed by the list (see for example
http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2009/002812.html and
http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2009/002730.html )
Also, 'condensation_and_evaporation' replaces 'precipitation' because latent
heating is the process which affects temperature, while precipitation can
occur without latent heat release (e.g. cloud droplets becoming rain drops)
Equivalently I propose that
tendency_of_specific_humidity_due_to_large_scale_precipitation (s-1)
should nave a new alias
tendency_of_specific_humidity_due_to_stratiform_cloud_condensation_and_evaporation
In both cases CMIP5 would use the new alias.
3/ Atmospheric convective mass fluxes
Extensions to the existing atmosphere_convective_mass_flux definition:
atmosphere_updraft_convective_mass_flux kg m-2 s-1
atmosphere_downdraft_convective_mass_flux kg m-2 s-1
atmosphere_shallow_convective_mass_flux kg m-2 s-1
For models with a distinct shallow convection scheme only.
atmosphere_deep_convective_mass_flux kg m-2 s-1 For models
with a distinct deep convection scheme only.
Received on Thu Jul 16 2009 - 07:24:35 BST
