Thanks Jonathan,
Indeed, heating and cooling degree-days are among the indices I am considering. May I suggest that the explanation to the standard name is updated; something along these lines:
integral_of_air_temperature_excess_wrt_time
"integral_of_Y_wrt_X" means int Y dX. The data variable should have an axis for X specifying the limits of the integral as bounds. "wrt" means with respect to. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. The air temperature excess is the air temperature minus the air temperature threshold, where only positive values are included in the integral. Its integral with respect to time is often called after its units of "degree-days".
And the corresponding change to the explanation of the standard_name integral_of_air_temperature_deficit_wrt_time
Furthermore, recalling your response to my recent question (
http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2016/058800.html) I suggest that a sentence elaborating on the temperature threshold should be included. You wrote
"The data variable of the integral should have a scalar coordinate variable or a size-one coordinate variable with the standard name of air_temperature_threshold, to indicate the threshold."
I guess this sentence could be added to end of the description, but why does it have to be a scalar or size-one coordinate variable? If we consider the practical example of heating degree-days the threshold may not be the same over a large region (as is the case for Europe), in which case one would like to have a two-dimensional threshold variable.
Kind regards,
Lars
-----Original Message-----
From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Jonathan Gregory
Sent: den 23 maj 2016 15:03
To: cf-metadata at cgd.ucar.edu
Subject: [CF-metadata] clarification of standard name integral_of_Y_wrt_X
Dear Lars
Best wishes
Jonathan
----- Forwarded message from B?rring Lars <Lars.Barring at smhi.se> -----
> Date: Mon, 23 May 2016 09:19:47 +0000
> From: B?rring Lars <Lars.Barring at smhi.se>
> To: "cf-metadata at cgd.ucar.edu" <cf-metadata at cgd.ucar.edu>
> Subject: [CF-metadata] clarification of standard name
> integral_of_Y_wrt_X
>
> Dear all,
>
> I am trying to find CF compliant representations of various degree-day indices and find the standard name with the following description:
>
> "integral_of_Y_wrt_X" means int Y dX. The data variable should have an axis for X specifying the limits of the integral as bounds. "wrt" means with respect to. Air temperature is the bulk temperature of the air, not the surface (skin) temperature. The air temperature excess is the air temperature minus the air temperature threshold. Its integral with respect to time is often called after its units of "degree-days".
>
>
> This seems suitable but just to clarify, does "air temperature excess" include 'negative excess'? E.g. is it integral(T-t) or is it integral(max(T-t),0)), where T is air temperature, and t is threshold temperature? This is not entirely clear from the explanation " air temperature excess is the air temperature minus the air temperature threshold".
>
>
>
> Many thanks,
> Lars
>
> --
> Lars B?rring
>
> FDr,Forskare / G?stprofessor,CEC/Lunds universitet
> PhD,Senior Scientist / Guest professor,CEC/Lund University
>
> SMHI / Swedish Meteorological and Hydrological Institute Rossby
> Centre SE - 601 76 NORRK?PING http://www.smhi.se
>
> E-post / Email: lars.barring at smhi.se
> Tel / Phone: +46 (0)11 495 8604
> Fax: +46 (0)11 495 8001
> Bes?ksadress / Visiting address: Folkborgsv?gen 17
>
> _______________________________________________
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----- End forwarded message -----
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Received on Mon May 23 2016 - 07:34:13 BST
