Dear Lars
I agree it is not clear and it should be. I think the intention was to mean
zero or positive, and not allow negative excesses, because there is also a
standard_name integral_of_air_temperature_deficit_wrt_time. My recollection is
that these were proposed for "heating degree days" and "cooling degree days".
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 integral_of_air_temperature_excess_wrt_time 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 -----
Received on Mon May 23 2016 - 07:02:34 BST
