Dear Alison,
Thanks for the information. I had been looking at an older version of
the standard names table by accident and missed this quantity. However,
after looking at it, I am a little confused by the phrase
"condensed_water." I think of condensed water as liquid water that has
condensed from water vapor, but definition states: "condensed_water"
means liquid and ice. Why is ice included here? Is "condensed" to be
interpreted more generally such that liquid and/or ice particles are
included in the cloud? If the latter, then why not use a more general
phrase such as "cloud_particle" to cover all types of possible
particles: e.g. liquid, ice, mixed liquid/ice? To me, the use of
"condensed_water" in the name then "liquid and ice" in the definition is
confusing.
If this standard name is meant apply to both liquid and/or ice particles
in the cloud, then I think that it could suffice for our GOES-R data
product, but in that case, I would suggest a minor re-write of the name.
Sincerely,
Jonathan
On 12/17/2013 6:58 AM, [email protected] wrote:
Dear Jonathan and Randy,
You are correct that we already have the standard name
effective_radius_of_cloud_liquid_water_particle_at_liquid_water_cloud_top which is obviously aimed
at liquid particles. We do, however, also have the existing name
effective_radius_of_cloud_condensed_water_particles_at_cloud_top defined as: 'The effective radius
of a size distribution of particles, such as aerosols, cloud droplets or ice crystals, is the area
weighted mean radius of particle size. It is calculated as the ratio of the third to the second
moment of the particle size distribution. "cloud_top" refers to the top of the highest
cloud. "condensed_water" means liquid and ice.' I think this is probably the quantity
you need, rather than adding another standard name.
Best wishes,
Alison
------
Alison Pamment Tel: +44 1235 778065
NCAS/British Atmospheric Data Centre Email: [email protected]
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.
From: CF-metadata [mailto:[email protected]] On Behalf Of
Jonathan Wrotny
Sent: 15 December 2013 21:56
To: [email protected]
Subject: [CF-metadata] Proposed new standard name:
effective_radius_of_cloud_particle_at_cloud_top
Dear CF board,
Back in May, a colleague of mine, Randy Horne, submitted a new proposed name for the
effective radius of a cloud particle at the top of a cloud. Our proposed standard name
was "effective_radius_of_cloud_particle_at_cloud_top". We did not hear back
from any CF posters at the time in regards to this proposal, and are hoping to re-start
this proposal now.
The motivation for this new standard name is a data product on the future
GOES-R geostationary platform. This product is the effective radius for a
cloud particle at the top of a cloud. The GOES-R product will not distinguish
between water and ice particles, however. Currently, the CF database has a
similar standard name but for liquid particles only
(effective_radius_of_cloud_liquid_water_particle_at_liquid_water_cloud_top).
This standard name does not suffice for the GOES-R data product, hence, the
proposal for a slightly more general standard name which would cover both water
and ice particles at the cloud top. Here is our current proposal:
Standard Name:
effective_radius_of_cloud_particle_at_cloud_top
Definition:
The effective radius of a size distribution of particles, such as aerosols,
cloud droplets or ice crystals, is the area weighted mean radius of particle
size. It is calculated as the ratio of the third to the second moment of the
particle size distribution. cloud_top refers to the top of the highest cloud
and cloud_particle refers to either a liquid water droplet or ice crystal.
Canonical Units:
m
Thanks for your consideration of this proposal. All comments are welcome.
Sincerely,
Jonathan Wrotny
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