Sorry, this email went just to Jonathan instead of the list. Stupid computers?.
It still appears timely, though.
John
Begin forwarded message:
> From: John Graybeal <graybeal at marinemetadata.org>
> Subject: Re: [CF-metadata] new standard name: total_totals_index
> Date: May 18, 2013 9:39:27 AM PDT
> To: Jonathan Gregory <j.m.gregory at reading.ac.uk>
>
> The totals appear from the definition to be not totals, but differences. Is there some reason it isn't called total_differences_index?
>
> And am I the only one who gets anxious at a name whose principal measured object is "totals" (or "differences")? They are differences of *particular* things, air temperatures and dew point temperatures -- which could be relevant when we want to total differences of other things, for example if one creates an atmospheric stability index based on differences in air densities and wind speeds.
>
> Jonathan's modifier goes a long way to limit the overreach, and I could imagine the topics being differenced could go into auxiliary metadata in some way. But I'll at least float my preference
>
> atmosphere_stability_total_differences_index_due_to_air_temperature_and_dew_point_temperature
>
> John
>
>
> On May 18, 2013, at 07:06, Jonathan Gregory <j.m.gregory at reading.ac.uk> wrote:
>
>> r Jonathan
>>
>>> total_totals_index
>>>
>>> with the associated definition:
>>>
>>> The Total Totals Index (TT) indicates the likelihood of severe
>>> convection. The index is derived from the difference in air
>>> temperature between 850 and 500 hPa (the vertical totals) and the
>>> difference between the dew point temperature at 850 hPa and the air
>>> temperature at 500 hPa (the cross totals). The vertical totals and
>>> cross totals are summed to obtain the Total Totals Index.
>>
>> This term is not self-explanatory and presents the same kind of difficulty as
>> "lifted index" (see my last email). In this case, however, it seems impossible
>> to devise a short definition. Moreover, unlike lifted index, it is not a
>> quantity applicable to any level; the two levels concerned are hard-wired into
>> the definition. It's a one-off ad-hoc empirical quantity.
>>
>> As a standard name, it would be good if we could add some context to it. For
>> instance, what about
>>
>> atmosphere_stability_total_totals_index
>>
>> If I have understood the definitions online and yours above, this quantity is
>> actually not a dimensionless index. Its unit is K, because it is calculated by
>> adding temperature differences.
>>
>> Best wishes
>>
>> Jonathan
>> _______________________________________________
>> CF-metadata mailing list
>> CF-metadata at cgd.ucar.edu
>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>
>
>
> ---------------
> John Graybeal
> Marine Metadata Interoperability Project: http://marinemetadata.org
> graybeal at marinemetadata.org
>
>
>
>
---------------
John Graybeal
Marine Metadata Interoperability Project:
http://marinemetadata.org
graybeal at marinemetadata.org
Received on Tue May 21 2013 - 16:12:43 BST
