Hi Jonathan, I suggested two such standard_names in an email on Friday, because I need them for various CAPE/CIN/etc standard_names:
air_pressure_of_lifted_parcel_at_start air_pressure_of_lifted_parcel_at_finish These would have the following definitions: Various stability and convective potential indices are calculated by "lifting" a parcel of air: moving it dry adiabatically from a starting height (often the surface) to the Lifting Condensation Level, and then wet adiabatically from there to an ending height (often the top of the data/model/atmosphere). air_pressure_of_lifted_parcel_at_start [finish] is the pressure height at the beginning [end] of lifting. Both would have canonical units of Pa We could then add the following final sentence to the definition for the total totals index: "If the index is calculated between non-standard heights, they should be specified using auxiliary coordinate variables of air_pressure_of_lifted_parcel_at_start and air_pressure_of_lifted_parcel_at_finish." Does that seem like it would work? Cheers, --Seth On Wed, 29 May 2013 18:17:49 +0100 Jonathan Gregory <[email protected]> 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 >> >>_______________________________________________ >> >>CF-metadata mailing list >> >>[email protected] >> >>http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >> > >> > >> > >> >_______________________________________________ >> >CF-metadata mailing list >> >[email protected] >> >http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >> > >----- End forwarded message ----- >_______________________________________________ >CF-metadata mailing list >[email protected] >http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
