Dear Burkhardt, Martin and Jonathan,
Apologies but I accidentally sent my previous message before I had finished typing it ... my full list of comments on the hail and graupel names will follow shortly.
Best wishes,
Alison
------
Alison Pamment Tel: +44 1235 778065
NCAS/Centre for Environmental Data Archival Email: alison.pamment at stfc.ac.uk
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.
-----Original Message-----
From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Alison Pamment - UKRI STFC
Sent: 18 April 2018 17:21
To: 'Burkhardt Rockel' <rockel at me.com>; CF-metadata (cf-metadata at cgd.ucar.edu) <cf-metadata at cgd.ucar.edu>
Subject: Re: [CF-metadata] Proposal for new standard names
Dear Burkhardt, Martin and Jonathan,
Thank you Burkhardt for these proposals for hail and graupel names and thanks to Martin and Jonathan for commenting.
The names themselves look fine. For the flux names graupel_fall_flux, hail_fall_flux and graupel_and_hail_fall_flux I think the units should be kg m-2 s-1 as for other precipitation flux names.
I agree with Martin's suggestion of basing the hail and graupel definitions on the AMS glossary and allowing the size criteria to be applied as appropriate, while still allowing for variations between models. I think it would be useful to add some sentences to the definitions to provide cross-references between the various names. This would help users to decide whether to use separate hail and graupel names or the combined names for their own data.
Burkhardt, please could you check through the names again and let me know if you are happy with them? If so, then I think these can all be included in the May standard name table update.
1. atmosphere_mass_content_of_graupel (kg m-2) ' "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Graupel consists of heavily rimed snow particles, often called snow pellets; often indistinguishable from very small soft hail except when the size convention that hail must have a diameter greater than 5 mm is adopted. Reference: American Meteorological Society Glossary
http://glossary.ametsoc.org/wiki/Graupel http://glossary.ametsoc.org/wiki/Graupel.'
2. atmosphere_mass_content_of_hail (kg m-2) ' "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Hail is precipitation in the form of balls or irregular lumps of ice, often restricted by a size convention to diameters of 5mm or more. Reference: American Meteorological Society Glossary
http://glossary.ametsoc.org/wiki/Hail http://glossary.ametsoc.org/wiki/Hail.'
I think this one is agreed. It is accepted for publication in the standard name table and will be added in the May update.
3. atmosphere_mass_content_of_graupel_and_hail (kg m-2) ' "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used.'
Just to be clear, is this the
------
Alison Pamment Tel: +44 1235 778065
NCAS/Centre for Environmental Data Archival Email: alison.pamment at stfc.ac.uk
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.
From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Burkhardt Rockel
Sent: 05 April 2018 15:50
To: Juckes, Martin (STFC,RAL,RALSP) <martin.juckes at stfc.ac.uk>
Cc: cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] Proposal for new standard names
Dear Martin,
here comes the next iteration. For completeness I added also the X_fall_amount and X_fall_fluxes by using rainfall and snowfall as templates.
Regards
Burkhardt
atmosphere_mass_content_of_graupel
units: kg m-2
"Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Graupel consists of heavily rimed snow particles, often called snow pellets; often indistinguishable from very small soft hail except when the size convention that hail must have a diameter greater than 5 mm is adopted. Reference: American Meteorological Society Glossary
http://glossary.ametsoc.org/wiki/Graupel http://glossary.ametsoc.org/wiki/Graupel.
atmosphere_mass_content_of_hail
units: kg m-2
"Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Hail is precipitation in the form of balls or irregular lumps of ice, often restricted by a size convention to diameters of 5mm or more. Reference: American Meteorological Society Glossary
http://glossary.ametsoc.org/wiki/Hail http://glossary.ametsoc.org/wiki/Hail .
atmosphere_mass_content_of_graupel_and_hail
units: kg m-2
"Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used.
mass_fraction_of_hail_in_air
units: 1
Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of X to the mass of Y (including X). Hail is precipitation in the form of balls or irregular lumps of ice, often restricted by a size convention to diameters of 5mm or more. Reference: American Meteorological Society Glossary
http://glossary.ametsoc.org/wiki/Hail http://glossary.ametsoc.org/wiki/Hail .
mass_fraction_of_graupel_and_hail_in_air
units: 1
Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of X to the mass of Y (including X).
hail_fall_amount
units: kg m-2
"Amount" means mass per unit area. Hail is precipitation in the form of balls or irregular lumps of ice, often restricted by a size convention to diameters of 5mm or more. Reference: American Meteorological Society Glossary
http://glossary.ametsoc.org/wiki/Hail http://glossary.ametsoc.org/wiki/Hail .
graupel_and_hail_fall_amount
units: kg m-2
"Amount" means mass per unit area.
graupel_fall_flux
units: kg m-2
In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. Graupel consists of heavily rimed snow particles, often called snow pellets; often indistinguishable from very small soft hail except when the size convention that hail must have a diameter greater than 5 mm is adopted. Reference: American Meteorological Society Glossary
http://glossary.ametsoc.org/wiki/Graupel http://glossary.ametsoc.org/wiki/Graupel.
hail_fall_flux
units: kg m-2
In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. Hail is precipitation in the form of balls or irregular lumps of ice, often restricted by a size convention to diameters of 5mm or more. Reference: American Meteorological Society Glossary
http://glossary.ametsoc.org/wiki/Hail http://glossary.ametsoc.org/wiki/Hail .
graupel_and_hail_fall_flux
units: kg m-2
In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics.
Am 05.04.2018 um 16:16 schrieb Martin Juckes - UKRI STFC <mailto:martin.juckes at stfc.ac.uk>:
Dear Burkhardt,
We could have an additional set of standard names:
atmospheric_mass_content_of_graupel_and_hail, and instruct modeling centres to use the one which fits their modeling approach.
But the UM presentation implies that they have a partition of the solid phase between ice, snow and graupel, while the AMS has an additional category of "small ice pellets".
It may be better to follow a pragmatic approach and relax the 5mm specification (especially as the concept of "diameter" is difficult to apply to an "irregular lump" of ice):
"Hail is precipitation in the form of balls or irregular lumps of ice, often restricted by a size convention to diameters of 5mm or more. Reference: American Meteorological Society Glossary
http://glossary.ametsoc.org/wiki/Hail ."
"Graupel consists of heavily rimed snow particles, often called snow pellets; often indistinguishable from very small soft hail except when the size convention that hail must have a diameter greater than 5 mm is adopted. Reference: American Meteorological Society Glossary
http://glossary.ametsoc.org/wiki/Graupel.
For CMIP6 we have some quantities which refer to all solid phases of water (e.g. in
http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2018/059965.html : precipitation_flux_of_solid_water_containing_2H) which would presumably be snow+graupel+hail+small ice pellets,
regards,
Martin
<
http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2018/059965.html>
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http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2018/059965.html>
________________________________
From: Burkhardt Rockel <mailto:rockel at me.com>
Sent: 05 April 2018 14:42:57
To: Juckes, Martin (STFC,RAL,RALSP); mailto:cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] Proposal for new standard names
Dear Martin,
thank you for your comments!
The difference of graupel and hail is mainly by the definition of the size as far as I know. Graupel: diameter sizes = 5mm. I guess models need to have a two-moment cloud scheme implemented to distinguish between graupel and hail.
In case of single moment schemes which are the general case in most atmospheric climate models, there is just one category for graupel+hail (if a model provides this at all). From
http://www.met.reading.ac.uk/~sws00rsp/teaching/nanjing/microphysics.pdf it reads that in the UM the graupel+hail is just called graupel. The naming is actually the same in the one moment schemes of COSMO-model and WRF.
I agree with your proposal to extend the description of hail.
Any idea on how to distinguish between the use of graupel definition in a one-moment scheme (graupel includes hail sizes) and in a two moment scheme (graupel < 5mm, hail >= 5mm)?
atmosphere_mass_content_of_graupel
units: kg m-2
"Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Graupel consists of heavily rimed snow particles, often called snow pellets; often indistinguishable from very small soft hail except for the size convention that hail must have a diameter greater than 5 mm. Reference: American Meteorological Society Glossary
http://glossary.ametsoc.org/wiki/Graupel.
atmosphere_mass_content_of_hail
units: kg m-2
"Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used. Hail is precipitation in the form of balls or irregular lumps of ice with a diameter of 5mm or more. Reference: American Meteorological Society Glossary
http://glossary.ametsoc.org/wiki/Hail .
mass_fraction_of_hail_in_air
units: 1
Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of X to the mass of Y (including X).
Regards
Burkhardt
Am 05.04.2018 um 13:32 schrieb Martin Juckes - UKRI STFC <mailto:martin.juckes at stfc.ac.uk<mailto:martin.juckes at stfc.ac.uk>>:
Dear Burkhardt,
the names look good to me, but I have a question about the precise definition of "hail", which has not previously been used in CF standard names. The existing name "graupel_fall_amount" cites the AMS definition for graupel : "Heavily rimed snow particles, often called snow pellets; often indistinguishable from very small soft hail except for the size convention that hail must have a diameter greater than 5 mm." The corresponding AMS definition for hail is:
Precipitation in the form of balls or irregular lumps of ice, always produced by convective clouds, nearly always cumulonimbus.
An individual unit of hail is called a hailstone. By convention, hail has a diameter of 5 mm or more, while smaller particles of similar origin, formerly called small hail, may be classed as either ice pellets or snow pellets. Thunderstorms that are characterized by strong updrafts, large liquid water contents, large cloud-drop sizes, and great vertical height are favorable to hail formation. The destructive effects of hailstorms upon plant and animal life, buildings and property, and aircraft in flight render them a prime object of weather modification studies. In aviation weather observations, hail is encoded A.
Is this what you intend with the proposed name, including the fixed size threshold of 5mm? I would have considered 4mm diameter balls of ice falling out of the sky as hail, but the 5mm rule appears to be part of the scientific definition of the term.
If so, we could add an abbreviated form of the AMS definition to the standard name descriptions:
"Hail is precipitation in the form of balls or irregular lumps of ice with a diameter of 5mm or more. Reference: American Meteorological Society Glossary
http://glossary.ametsoc.org/wiki/Hail ."
regards,
Martin
________________________________
From: CF-metadata <mailto:cf-metadata-bounces at cgd.ucar.edu<mailto:cf-metadata-bounces at cgd.ucar.edu>> on behalf of Burkhardt Rockel <mailto:rockel at me.com<mailto:rockel at me.com>>
Sent: 04 April 2018 14:13
To: mailto:cf-metadata at cgd.ucar.edu<mailto:cf-metadata at cgd.ucar.edu>
Subject: Re: [CF-metadata] Proposal for new standard names
Dear Alison et al.
any progress in putting the below proposed standard names into official CF standard name table?
Regards
Burkhardt
Am 30.11.2017 um 19:00 schrieb Jonathan Gregory <mailto:j.m.gregory at reading.ac.uk<mailto:j.m.gregory at reading.ac.uk>>:
Dear Burkhardt
These fit existing patterns, I believe, so they should be fine. Thanks.
Best wishes
Jonathan
----- Forwarded message from Burkhardt Rockel <mailto:rockel at me.com<mailto:rockel at me.com>> -----
Date: Wed, 29 Nov 2017 14:03:14 +0100
From: Burkhardt Rockel <mailto:rockel at me.com<mailto:rockel at me.com>>
To: mailto:cf-metadata at cgd.ucar.edu<mailto:cf-metadata at cgd.ucar.edu>
Subject: [CF-metadata] Proposal for new standard names
X-Mailer: Apple Mail (2.3445.4.7)
I propose the following standard names:
atmosphere_mass_content_of_graupel
units: kg m-2
"Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used.
atmosphere_mass_content_of_hail
units: kg m-2
"Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including content_of_atmosphere_layer are used.
mass_fraction_of_hail_in_air
units: 1
Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of X to the mass of Y (including X).
Regards
Burkhardt Rockel
-----------
Dr. Burkhardt Rockel
Helmholtz-Zentrum Geesthacht
Institute of Coastal Research / Group Regional Atmospheric Modeling Max-Planck-Strasse 1
D-21502 Geesthacht
Germany
Phone: +49 4152 87 1803
Fax: +49 4152 87 4 1803
Email: Burkhardt.Rockel (at)
http://hzg.de<
http://hzg.de> <
http://hzg.de/>
www:
http://rockel.staff.coast.hzg.de <
http://rockel.staff.coast.hzg.de/>
coordinates: 53.40575 N, 10.428697 E
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Received on Wed Apr 18 2018 - 10:29:00 BST
