[RegCNET] mismatch in averaging!

[Smz Rcm]

Dear Sir, 
In some tests I got Tmin too small or too big in continuous than in diurnal! do you think that maybe I have a problem?
In tests, I found some strenge values of Tmin when I use continuous averaging (for exemple Tmin equals 7°C in July!!, but when I took the min of the 8 sub-daily averages of the diurnal, I got a value of 21°C which is 98% the observation value!)

regards
Sassi

 
--- En date de : Ven 11.12.09, Moetasim Ashfaq <moetasim at stanford.edu> a écrit :

De: Moetasim Ashfaq <moetasim at stanford.edu>
Objet: Re: [RegCNET] mismatch in averaging!
À: "Smz Rcm" <smzrcm at yahoo.fr>
Cc: "bixq" <bixq at ictp.it>, regcnet at lists.ictp.it
Date: Vendredi 11 Décembre 2009, 17h52

Hi,
Why Diurnal avg and Continuous daily avg should give you same results? 
In postproc, we consider daily average of tmax (tmin) as the max (min) of all daily time-steps not the average of them. Similarly, 5-day mean will be calculated after calculating daily max (min) for each day and then averaging that from day1 to day5 and so on. Only in the case of diurnal cycle, first sub-daily tmax/tmin will be the average of all first sub-daily time-steps, second sub-daily tmax/tmin will be the average of all second sub-daily time-steps and so on.
Now, averaging final 8 diurnal time steps will not give you correct daily average, therefore, that output should ONLY be used for diurnal analysis. 
Moet

 
On Dec 11, 2009, at 2:41 AM, Smz Rcm wrote:
I used postproc.x 
but in postproc.in there are: DIURNALI AVG and CONTINUOUS AVG!
these two options don't give the same result for Tmin and Tmax
so wich I have to use?
regards

--- En date de : Ven 11.12.09, bixq <bixq at ictp.it> a écrit :

De: bixq <bixq at ictp.it>
Objet: Re: [RegCNET] mismatch in averaging!
À: "Smz Rcm" <smzrcm at yahoo.fr>
Cc: regcnet at lists.ictp.it
Date: Vendredi 11 Décembre 2009, 10h34


Hi, Sassi:

Correct ! for the following 5 fields in SRF file:
tgmax, tgmin, t2max, t2min, w10max and ps_min

You have to run postproc.f (or day_SRF.f) firstly.

(https://lists.ictp.it/pipermail/regcnet/2009/001900.html)

On Fri, 11 Dec 2009, Smz Rcm wrote:

> Dear RegCMers,
> I tried some simulations using ReGCM3 with ERA40 and with EH50M data, but after the postprocessing step, I had some doubt about Tmin and Tmax values, because when I make a diurnal averaging I get more realistic values than when making daily continuous averaging. and the difference is really important!
> so what should I do please? I get Tmin and Tmax from the 8 averaged values of diurnal file?
> Thanks for help
> Sassi
> 
> 
> 
> 

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  Dr. Xunqiang Bi         email:bixq at ictp.it
  Earth System Physics Group
  The Abdus Salam ICTP
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