Folks: The current definition for
"atmosphere_optical_thickness_due_to_cloud" in the current standard name
table is:
The optical thickness is the integral along the path of radiation of a
volume scattering/absorption/attenuation coefficient. The radiative flux
is reduced by a factor exp(-optical_thickness) on traversing the path. A
coordinate variable of radiation_wavelength or radiation_frequency can
be specified to indicate that the optical thickness applies at specific
wavelengths or frequencies. The atmosphere optical thickness applies to
radiation passing through the entire atmosphere. 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.
There are other "atmospheric_optical_thickness_due_to_<process>" standard
names in the table, and they all have a clarifying sentence about the
"<process>" part. The definition for
"atmosphere_optical_thickness_due_to_cloud" does not have a clarifying
sentence for what a cloud means. Is this a mistake ? If so, maybe the
following changes should be made to the standard name table: (1) Add a
standard_name "atmosphere_optical_thickness" and use the current definition
for "atmosphere_optical_thickness_due_to_cloud" as identified above. (2)
Change the definition of "atmosphere_optical_thickness_due_to_cloud" to be:
The optical thickness is the integral along the path of radiation of a
volume scattering/absorption/attenuation coefficient. The radiative flux
is reduced by a factor exp(-optical_thickness) on traversing the path. A
coordinate variable of radiation_wavelength or radiation_frequency can
be specified to indicate that the optical thickness applies at specific
wavelengths or frequencies. The atmosphere optical thickness applies to
radiation passing through the entire atmosphere. "Cloud" means the
component of extinction owing to the presence of liquid or ice water
particles. 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.
very respectfully, randy
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <
http://mailman.cgd.ucar.edu/pipermail/cf-metadata/attachments/20130418/f7cea237/attachment.html>
Received on Thu Apr 18 2013 - 12:01:17 BST
