[ncl-talk] plotting monthly climatology form hourly data

[Setareh Rahimi]

Dear Dennis,
Thank you so much for your explanations and guidance. However, I noticed
that the results for every year are similar to each other. Please have look
at the attached files. This is not reasonable.  I see no problems in the
script, so why this happened?
Best wishes,

On Fri, Nov 8, 2019 at 4:36 AM Dennis Shea <shea at ucar.edu> wrote:

> The issue is the variable "time". This a subtle issue.
>
>   f        = *addfile*("khuzetan_DUST04.2000010100.nc", "r")
>   time  = f->time
>   timeb = f->time_bnds
>
>   ymdh_tag = *cd_calendar*
> <http://www.ncl.ucar.edu/Document/Functions/Built-in/cd_calendar.shtml>(time
>      ,-3)
>   ymdh_Strt= *cd_calendar*
> <http://www.ncl.ucar.edu/Document/Functions/Built-in/cd_calendar.shtml>(timeb(:,0),-3)
> ; beginning time 'bound'
>   ymdh_Last= *cd_calendar*
> <http://www.ncl.ucar.edu/Document/Functions/Built-in/cd_calendar.shtml>(timeb(:,1),-3)
> ; ending time 'bound'
>
>   print(timeb(:,0)+"  "+timeb(:,1)+"  "+time+"  " \
>        +ymdh_Strt +"  "+ymdh_Last +"  "+ymdh_tag)
> =============
> One month of time values. Here 124 (31*4) January hours.
>
> (0)     timeb_0  timeb_1   time       ymdh_Strt    ymdh_Last       ymdh_tag
>           439032  439038  439038  2000*010100*  2000*010106*  2000*010106*
> *                :            :             :
> :                     :                    :*
> (123) 439770  439776  439776  2000*013118*  2000*020100*  2000
> *020100*
> ===============
>
> *The last tag value [timeb(:,1)] for the month of JANUARY is FEBRUARY
> !!!  *
>
> *My personal view is that this is not the appropriate time tag. *
>
> *Rather, the timeb(:,0)]  should be used. *
> ================
>
> In a nutshell, the work-around is to reassign the time coordinate
> associated with each variable.
>
>   timebnd = a[:]->time_bnds
>   time0   = timebnd(:,0)                        ; extract the start bound
>   [SNIP]
>   x  = a[:]->emflx                     ; read emission flux from all files
>   x&time = time0                     ; reassign original 'tag' time
> [SNIP]
>   u = b[:]->uas(:,0,:,:)              ; read U from all files
>   u&time = time0                     ; reassign original 'tag' time
>
>   v = b[:]->vas(:,0,:,:)              ; read V from all files
>   v&time = time0                     ; reassign original 'tag' time
>
> =========
> Comments:
> [0] You MUST examine the time variable more carefully.
>       Using yyyymmdd start/stop dates is not appropriate for yyyymmddhh.
> [1] You do *not *have to compute the daily mean values
> [2] *calculate_monthly_values*
> <http://www.ncl.ucar.edu/Document/Functions/Contributed/calculate_monthly_values.shtml>
> will accept 6-hrly data
> [3] *http://www.ncl.ucar.edu/Applications/rcm.shtml*
> <http://www.ncl.ucar.edu/Applications/rcm.shtml>
> Examples 5,6,7: illustrate how to plot variables for the Regional Climate
> Model (RCM).
> =========
> See Attached
>
>
> On Thu, Nov 7, 2019 at 6:10 AM Setareh Rahimi via ncl-talk <
> ncl-talk at ucar.edu> wrote:
>
>> Dear all,
>>
>> I need to plot the monthly average from a model output, which gives me
>> 4times data per day( at 00, 06,12,18). So I first need to convert hourly
>> data tp daily data and then convert to monthly. And finally calculates the
>> climatology average of those monthly data from 2000-2014.
>> However, once I ran my script I faced some error:
>> 1. I did not have data for 2015, but when using print (yyyymmdd)   year
>> 2015 printed. ( please have a look at the attachment number 1)
>> 2. After reading variable x this warning comes up: Aggregated dimension
>> coordinate values are non-monotonic; check aggregated file ordering
>> (warning attached)
>> 3. Once using clmMonTLL function ( available on :
>> https://www.ncl.ucar.edu/Applications/Scripts/climo_3.ncl), NCL tells
>> that :  clmMonTLL: dimension must be a multiple of 12 . I just wonder
>> why this happened. I used 15 years with 12 months for each year!! (
>> attached)
>> I attached the script and data for the year 2000. Could you please
>> kindly guide me what are my mistakes?
>> Best wishes,
>>  str.zip
>> <https://drive.google.com/file/d/12-n6pQ4JF6nwIRBVW4iaTKaznfP1FGet/view?usp=drive_web>
>>
>> --
>> S.Rahimi
>>
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>
>

-- 
S.Rahimi
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