Dear Jonathan,
Thanks for the information. I will definitely go with your suggestion -
simplicity is good. Here is the current proposal:
Standard Name:
atmosphere_stability_total_totals_index
Definition:
The atmosphere_stability_total_totals_index indicates the likelihood of severe
convection and is often referred to as simply the
total totals index. 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 index.
Canonical Units: K
Sincerely,
Jonathan
On 5/29/2013 1:17 PM, Jonathan Gregory wrote:
Dear Jonathan
It would be all right to specify coordinate variables (size one or scalar)
for the two levels, but they would have to be distinguishable. That means
they'd have to have different standard names, I suppose - what would they be?
It seems to me this would then tend towards the generalisation of this
quantity, for which you didn't see an immediate need when you proposed it.
It would be simpler to remain hard-wired, if that's the use-case.
Best wishes
Jonathan
----- Forwarded message from Jonathan Wrotny <[email protected]> -----
Date: Wed, 29 May 2013 12:00:42 -0400
From: Jonathan Wrotny <[email protected]>
User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:17.0) Gecko/20130509
Thunderbird/17.0.6
To: Jonathan Gregory <[email protected]>, John Graybeal
<[email protected]>, [email protected]
Subject: Re: [CF-metadata] new standard name: total_totals_index
Jonathan,
I wanted to make a minor addition to the definition of the total
totals index to include coordinate variables for the 850 and 500 hPa
pressure levels. It seems that this information might be useful to
have in a netCDF file, but not be specifically required. Please let
me know if you think this sentence is unnecessary and I can remove.
Standard Name:
atmosphere_stability_total_totals_index
Definition:
The atmosphere_stability_total_totals_index indicates the
likelihood of severe convection and is often referred to as simply the
total totals index. 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 index.Coordinate variables can be specified
which
indicate the 850 and 500 hPa pressure levels.
Canonical Units: K
Does this standard name/definition/units seems suitable to the CF board?
FYI, I will be submitting two other stability indices this week. Sincerely,
Jonathan
On 5/22/2013 1:42 PM, Jonathan Wrotny wrote:
Dear Jonathan,
Thanks for your feedback. I agree with your suggested
modifications the definition and have included them below.
Also, there is an e-mail from John Graybeal who is suggesting a
more generalized version of the standard name. I have thought
about attempting to come up with a similar, general, name for the
total totals index. But, this name was so long that I believe
that it would itself become a full description, which I was trying
to avoid. John's suggested name boils it down more generally and
succintly, but it turns out that this name could also be
applicable to the stability index, "k index," which I am going to
submit in the coming days (which also uses differences of the
ambient and dew point temperatures), so there would be conflict
with the "k index" name. Also, remember that the total totals is
not a name that I have personally constructed to describe the
mathematics of the quantity, but it is actually the name of an
commonly used meteorological quantity.
Given Jonathan's previous direction (see e-mails concerning
"lifted index") to attempt to standardize all names except for
those specific, complex quantities that don't lend themselves to
generalization, I think keeping total_totals_index in the standard
name is a good idea. I think the lifted index is complex and
specific enough that it falls into the category or meriting a
unique name (similar to, say, the NDVI).
Standard Name:
atmosphere_stability_total_totals_index
Definition:
The atmosphere_stability_total_totals_index indicates the
likelihood of severe convection and is often referred to as simply the
total totals index. 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 index.
Canonical Units: K
Sincerely,
Jonathan
On 5/21/2013 5:39 PM, Jonathan Gregory wrote:
Dear Jon
I agree with your assessment, and I like your proposed name. My
only question remains with the definition. It seems like there
could be two approaches given the specific nature of the product: 1)
write the definition as below with hard-wired pressure levels part
of the definition. Based on my understanding of the product, I have
never seen any other pressures levels other than 500 and 850 hPa
used for the index, but I could be wrong. -or- 2) attempt to
generalize the definition so that it does not mention the specific
pressure levels. This would help to generalize the definition, but
may not add that much value since other pressure levels do not
appear to be commonly used (ever?).
If that is the case, then (1) seems the better choice
Standard Name: atmosphere_stability_total_totals_index
Definition:
Option 1)The atmosphere_stability_total_totals_index indicates the
likelihood of severe convection and is often referred to as simply
the total totals index. 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 index.
You could insert
often referred to as simply the total totals index
as in your other definition. This bit:
Air temperature is
the bulk temperature of the air, not the surface (skin) temperature.
The term "surface" means the lower boundary of the atmosphere.
doesn't seem necessary in this case, since "surface" is not mentioned.
Canonical Units: K
Oh, good. :-)
If we define it specifically now, that does not preclude the later addition of
a more general standard name if required.
Cheers
Jonathan
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