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 <[email protected]> on behalf of Burkhardt 
Rockel <[email protected]>
Sent: 04 April 2018 14:13
To: [email protected]
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 <[email protected]>:
>
> Dear Burkhardt
>
> These fit existing patterns, I believe, so they should be fine. Thanks.
>
> Best wishes
>
> Jonathan
>
> ----- Forwarded message from Burkhardt Rockel <[email protected]> -----
>
>> Date: Wed, 29 Nov 2017 14:03:14 +0100
>> From: Burkhardt Rockel <[email protected]>
>> To: [email protected]
>> 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/>
>> www: http://rockel.staff.coast.hzg.de <http://rockel.staff.coast.hzg.de/>
>> coordinates: 53.40575 N, 10.428697 E
>> -----------
>>
>>
>>
>>
>>
>
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>
> ----- End forwarded message -----
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