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> <http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2018/059965.html> ________________________________ From: Burkhardt Rockel <roc...@me.com> Sent: 05 April 2018 14:42:57 To: Juckes, Martin (STFC,RAL,RALSP); cf-metadata@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 ; hail >= 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 <martin.juc...@stfc.ac.uk<mailto:martin.juc...@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 <cf-metadata-boun...@cgd.ucar.edu<mailto:cf-metadata-boun...@cgd.ucar.edu>> on behalf of Burkhardt Rockel <roc...@me.com<mailto:roc...@me.com>> Sent: 04 April 2018 14:13 To: cf-metadata@cgd.ucar.edu<mailto:cf-metadata@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 <j.m.greg...@reading.ac.uk<mailto:j.m.greg...@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 <roc...@me.com<mailto:roc...@me.com>> ----- Date: Wed, 29 Nov 2017 14:03:14 +0100 From: Burkhardt Rockel <roc...@me.com<mailto:roc...@me.com>> To: cf-metadata@cgd.ucar.edu<mailto:cf-metadata@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) 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 ----------- _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu<mailto:CF-metadata@cgd.ucar.edu> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu<mailto:CF-metadata@cgd.ucar.edu> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu<mailto:CF-metadata@cgd.ucar.edu> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
