Hi all -
I thought I should re-post this with a more clear subject line, in case
anyone else wants to to weigh in on the definitions, or lack
thereof, of albedo and air pressure.
Are these self-describing enough that they don't need to be
defined in CF? Or should we add at least a minimal definition?
Thanks -
Nan
On 7/14/15 3:22 PM, Nan Galbraith wrote:
Thanks for raising this, Maarten; we should fix the albedo
definitions. I use
surface_albedo regularly, but didn't actually have a definition handy,
so went
googling.
This one's from wikipedia:
Albedo is the ratio of reflected radiation from the surface to incident
radiation upon it. Its dimensionless nature lets it be expressed as a
percentage and is measured on a scale from zero for no reflection of
a perfectly black surface to 1 for perfect reflection of a white surface.
This one's from ESR.org (earth and space research) and is narrower,
specific
to earth's surface:
Albedo is the fraction of solar energy (shortwave radiation) reflected
from
the Earth back into space. It is a measure of the reflectivity of the
earth's
surface.
I propose we could add the sentence 'Albedo is the ratio of reflected
radiation from
the surface to incident radiation upon it' - or something similar - to
all 3 albedo
definitions.
For air_pressure_at_cloud_top, well, the definition of air_pressure is
'No help available.'
so I guess that's a problem.
If we use sea_water_pressure as an example, here's that definition:
'"Sea water pressure" is
the pressure that exists in the medium of sea water.' True enough.
Cheers - Nan
On 7/10/15 10:47 AM, Maarten Sneep wrote:
Hi,
I came across a few descriptions in the standard name list that seem
'off', or clearly unclear.
surface_albedo: "The surface called "surface" means the lower
boundary of the atmosphere." (this doesn't define albedo itself).
planetary_albedo: "No help available."
cloud_albedo: "The albedo of cloud." (this doesn't define albedo
itself either, and is not very specific).
air_pressure_at_cloud_top: "cloud_top refers to the top of the
highest cloud." (This apears very much a modelled parameter, not a
parameter from some remote sensing technique. Either the description
is kept deliberately vague, or I miss something. It is hard to use
this description on observations).
I'm sure there are more, but these caught my eye. I'm not sure how to
change the descriptions, I don't know the history of these quantities
in the standard name list. Can someone advise how to proceed?
Best,
Maarten Sneep
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