[CF-metadata] Final 17 terms for CMIP6 LS3MIP: Heat flux into snowpack

Alison Pamment - UKRI STFC alison.pamment at stfc.ac.uk
Wed Jul 4 04:48:39 MDT 2018


Dear Martin and Jonathan,

Thank you both for the very useful discussion of these names. I agree with Martin that the existing sensible_heat_flux names probably should become turbulent_heat_flux names. There are only four of them, but I will address those in a separate thread.

For the LS3MIP heat flux name we now have:
tendency_of_thermal_energy_content_of_surface_snow_due_to_rainfall_temperature_excess_above_freezing
'The phrase "tendency_of_X" means derivative of X with respect to time. "Content" indicates a quantity per unit area.Thermal energy is the total vibrational energy, kinetic and potential, of all the molecules and atoms in a substance. The phrase "surface_snow" means snow lying on the surface. The quantity with standard name tendency_of_thermal_energy_content_of_surface_snow_due_to_rainfall_temperature_excess_above_freezing is the heat energy carried by rainfall reaching the surface. It is calculated relative to the heat that would be carried by rainfall reaching the surface at zero degrees Celsius. It is calculated as the product QrainCpTrain, where Qrain is the mass flux of rainfall reaching the surface (kg m-2 s-1), Cp is the specific heat capacity of water and Train is the temperature in degrees Celsius of the rain water reaching the surface. 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.'

This name is accepted for publication in the standard name table and will be added in the next update.

For the river water names we have one vote for
> inward_water_volume_transport_along_river_channel
> outward_water_volume_transport_along_river_channel
and one for
> incoming_water_volume_transport_along_river_channel
> outgoing_water_volume_transport_along_river_channel.

Martin, it looks as though you will have the casting vote! Which do you prefer?

Best wishes,
Alison

________________________________________
From: CF-metadata <cf-metadata-bounces at cgd.ucar.edu> on behalf of Martin Juckes - UKRI STFC <martin.juckes at stfc.ac.uk>
Sent: 03 July 2018 12:02
To: cf-metadata at cgd.ucar.edu; j.m.gregory at reading.ac.uk
Subject: Re: [CF-metadata] Final 17 terms for CMIP6 LS3MIP: Heat flux into snowpack 
 

Dear Alison, Jonathan,


Thanks for these final suggestions. I agree with these proposals. I have a reservation about the interpretation of "sensible heat flux" which was mentioned in the discussion, but that does not need to delay approval of these proposed terms which neatly avoid the problem.


The usage of "sensible heat flux" outside the standard name list consistently refer to it as a thermodynamic property, not something which is specific to a particular medium. In the existing standard names which include the phrase "sensible_heat_flux" the descriptive text suggests that it applies to heat flux through air alone, implicitly excluding any heat flux conveyed by precipitation. It looks to me as though the wording is a reflection of the state of models at the time the standard names were defined, when it may have been reasonable to omit mention of transport of heat by precipitation and equate sensible heat flux at the surface to turbulent heat flux at the surface. As models can now, apparently, resolve the sensible heat flux associated with falling rain, I can't see any reason for maintaining an interpretation of "sensible_heat_flux" in standard names which conflicts with the normal usage.


regards,

Martin

________________________________
From: CF-metadata <cf-metadata-bounces at cgd.ucar.edu> on behalf of Jonathan Gregory <jonathan.gregory at ncas.ac.uk>
Sent: 01 July 2018 18:27
To: cf-metadata at cgd.ucar.edu
Subject: [CF-metadata] Final 17 terms for CMIP6 LS3MIP: Heat flux into snowpack

Dear Alison and Martin

> tendency_of_thermal_energy_content_of_surface_snow_due_to_rainfall_temperature_excess_above_freezing

I think this  suggestion of Alison's is very good, to describe the rainfall
temperature flux as a change in heat content due to X rather than as the
problematic X heat flux. Thanks.

> inward_water_volume_transport_along_river_channel
> outward_water_volume_transport_along_river_channel
> OR
> incoming_water_volume_transport_along_river_channel
> outgoing_water_volume_transport_along_river_channel.

I prefer the latter pair still, but I don't mind.

Best wishes

Jonathan
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