Hi Alison,
I'm not really qualified to provide expert guidance in this area, but
from an outsider's perspective:
I think your proposed modifications (for making these names a bit more
explicit) would be helpful to someone like me.
best regards,
Karl
On 3/13/18 9:50 AM, [email protected] wrote:
Dear Karl, All,
Apologies for taking a while to look at these names. Yes, there is a difference
between the two names subsurface_litter_carbon_content and
surface_litter_carbon_content.
Most litter name definitions contain the sentence ' "Litter" is dead plant material in or
above the soil' which I think I originally adapted from the "litter carbon" description
of these two quite old names. I understand surface_litter_carbon_content to mean the carbon content
of litter lying above the soil surface whereas subsurface_litter_carbon_content pertains to litter
buried within the soil. The sum of the two would be the quantity with the standard name
litter_carbon_content. The definitions of all three names should be updated. Furthermore, they
should really be mass_content names like the new ones we have just introduced for C4MIP, e.g.
litter_mass_content_of_13C.
I suggest we introduce aliases as follows:
surface_litter_carbon_content becomes surface_litter_mass_content_of_carbon (kg
m-2)
' "Litter" is dead plant material in or above the soil. "Surface litter" means the part
of the litter resting above the soil surface. "Content" indicates a quantity per unit area. The sum
of the quantities with standard names surface_litter_mass_content_of_carbon and
subsurface_litter_mass_content_of_carbon has the standard name litter_mass_content_of_carbon.'
subsurface_litter_carbon_content becomes
subsurface_litter_mass_content_of_carbon (kg m-2)
' "Litter" is dead plant material in or above the soil. "Subsurface litter" means the
part of the litter mixed within the soil below the surface. "Content" indicates a quantity per unit
area. The sum of the quantities with standard names surface_litter_mass_content_of_carbon and
subsurface_litter_mass_content_of_carbon has the standard name litter_mass_content_of_carbon.'
litter_carbon_content becomes litter_mass_content_of_carbon (kg m-2)
' "Litter" is dead plant material in or above the soil. "Content" indicates a
quantity per unit area. The sum of the quantities with standard names
surface_litter_mass_content_of_carbon and subsurface_litter_mass_content_of_carbon has the standard
name litter_mass_content_of_carbon.'
Are these okay?
While we're looking at these I think we should also update the existing name litter_carbon_flux, defined as '
"Litter carbon" is dead inorganic material in or above the soil quantified as the mass of carbon
which it contains. The litter carbon flux is the rate of production of litter. In accordance with common
usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in
physics.' Fortunately the definition does make it clear that it's a flux into the litter, but the name itself
is rather uninformative. Also, if the litter is dead plant material, then presumably the flux is from
vegetation to litter. So I'd suggest updating this to be more similar to the new C4MIP names:
litter_carbon_flux becomes mass_flux_of _carbon_into_litter_from_vegetation (kg
m-2 s-1)
' "Litter" is dead plant material in or above the soil. In accordance with common usage in
geophysical disciplines, "flux" implies per unit area, called "flux density" in physics.'
That would make this one the sum of Chris's new C4MIP names
mass_flux_of_carbon_into_litter_from_vegetation_due_to_mortality and
mass_flux_of_carbon_into_litter_from_vegetation_due_to_senescence wouldn't it?
Do others agree?
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 [mailto:[email protected]] On Behalf Of Karl
Taylor
Sent: 03 February 2018 06:42
To: [email protected]
Subject: [CF-metadata] two standard names for same quantity?
I noticed that "subsurface_litter_carbon_content" has the same "definition" as
"surface_litter_carbon_content": "Content" indicates a quantity per unit area. "Litter carbon" is dead plant
material in or above the soil quantified as the mass of carbon which it contains. The surface called "surface" means the lower
boundary of the atmosphere.
Is there a difference or are these two names aliases for the same quantity?
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