[ncl-talk] SPI calculation
Soma Roy
somaroy892 at gmail.com
Thu Nov 29 22:29:16 MST 2018
Hello Mary,
I just want to know that what is the more efficient way to save the
variable "spi" as a netcdf for multiple runlen?
Say 3,6,9 and 12 or 12 and 24 as mentioned in the spi_2.ncl script.
I want to save all runlen in a single netcdf file in single run time.
Please kindly inform me.
Thanking you,
Soma
On Thu, Nov 29, 2018, 20:12 Dennis Shea <shea at ucar.edu wrote:
> I do not understand: *"197207 with 3 month running avg"*
>
>
> If you used:
>
>
>
> *runlen = (/ 12, 24 /) *
>
> and your source array is dimensioned:
> *(time,lat,lon) ==> (492,129,135)*then your SPI variable should be
>
>
>
> *[len | 2] x [time | 492] x [lat | 129] x [lon | 135]*and your source array is dimensioned:
> * (time,lon,lat) ==> (492,135,129)*then your SPI variable should be
>
>
>
>
>
>
> *[len | 2] x [time | 492] x [lon | 135] x [lat | 129] --- 0 1 2 3---*
>
> *IF* you want to perform a 3-month running average of the 12 and 24 run-lengths
>
> nrun = 3
> opt = ? ; read documentation
> tdim = 1 ; time dimension
> spi3= *runave_n_Wrap* <http://www.ncl.ucar.edu/Document/Functions/Contributed/runave_n_Wrap.shtml> (spi, nrun, tdim, opt)
>
> *printVarSummary*(spi3)
>
> ========
>
>
>
>
>
> On Thu, Nov 29, 2018 at 1:15 AM Soma Roy <somaroy892 at gmail.com> wrote:
>
>> Hello Mary,
>>
>> I save the data of 'spi' as netcdf file.
>>
>> Where dimension of the data is like below;
>> spi(135x129x492) ; (lon, lat, spi values)
>>
>> Now my question is if I want to select 197207 with 3 month running avg.
>> Then how to select those indices from 3rd dimension of the matrix "spi"?
>>
>> Start yr is 1970.
>>
>> Please kindly inform me.
>>
>> Thanking you,
>> Soma
>>
>> On Thu, Nov 29, 2018, 12:39 Oluwaseun Ilori <wilseun at gmail.com wrote:
>>
>>> Good day, please could you assist with the correct script of the spi
>>> calculation, I'm having problem listing the result of the one I'm doing to
>>> text file for further analysis on ArcGis.
>>>
>>> Thanks
>>>
>>> On Thu, Nov 29, 2018, 7:47 AM Soma Roy <somaroy892 at gmail.com wrote:
>>>
>>>> I fixed the issue. Please ignore my last mail.
>>>>
>>>> Soma
>>>>
>>>> On Thu, Nov 29, 2018, 11:07 Soma Roy <somaroy892 at gmail.com wrote:
>>>>
>>>>> Hello Mary,
>>>>>
>>>>> I am using the attached script. Modified it as per your hints. But
>>>>> getting some errors at run time.
>>>>>
>>>>> printVarSummary of the data is as follows;
>>>>> Variable: prc
>>>>> Type: double
>>>>> Total Size: 73560960 bytes
>>>>> 9195120 values
>>>>> Number of Dimensions: 3
>>>>> Dimensions and sizes: [time | 528] x [lat | 129] x [lon | 135]
>>>>> Coordinates:
>>>>> time: [ 360..1068]
>>>>> lat: [ 6.5..38.5]
>>>>> lon: [66.5.. 100]
>>>>> Number Of Attributes: 3
>>>>> _FillValue : -999
>>>>> long_name : GRIDDED RAINFALL
>>>>> missing_value : -999
>>>>> : min=0 max=222.9121398925781
>>>>>
>>>>> I am getting the following errors;
>>>>> fatal:Dimension sizes of left hand side and right hand side of
>>>>> assignment do not match
>>>>> fatal:["Execute.c":8640]:Execute: Error occurred at or near line 47 in
>>>>> file spi_2.ncl
>>>>>
>>>>> fatal:NclOneDValGetClosestIndex: Non-monotonic coordinate value being
>>>>> used, can't complete coordinate subscript
>>>>> fatal:Could not obtain coordinate indexes, unable to perform subscript
>>>>> fatal:["Execute.c":8640]:Execute: Error occurred at or near line 82 in
>>>>> file spi_2.ncl
>>>>>
>>>>> Please kindly inform me how to correct it.
>>>>>
>>>>> Thanking you,
>>>>> Soma
>>>>>
>>>>>
>>>>> On Thu, Nov 29, 2018 at 9:51 AM Soma Roy <somaroy892 at gmail.com> wrote:
>>>>>
>>>>>> Thank you very much.
>>>>>>
>>>>>> Soma
>>>>>>
>>>>>> On Thu, Nov 29, 2018, 02:28 Mary Haley <haley at ucar.edu wrote:
>>>>>>
>>>>>>> Soma,
>>>>>>>
>>>>>>> The spi_2.ncl script shows you how to calculate the yyyymm variable:
>>>>>>>
>>>>>>> year = yyyymm/100
>>>>>>> yrStrt = year(0)
>>>>>>> yrLast = year(ntim-1)
>>>>>>> nyear = yrLast-yrStrt+1
>>>>>>> yyyymm = yyyymm_time(yrStrt, yrLast, "integer")
>>>>>>>
>>>>>>> You don't need the "date" or "yyyymm" arrays, because you already
>>>>>>> have the year information. Use ispan to generate the "year" array and now
>>>>>>> you can get your yyyymm and yrfac values as needed:
>>>>>>>
>>>>>>> year = ispan(1970,2010,1)
>>>>>>> ntim = dimsizes(year)
>>>>>>> yrStrt = year(0)
>>>>>>> yrLast = year(ntim-1)
>>>>>>> nyear = yrLast-yrStrt+1
>>>>>>> yyyymm = yyyymm_time(yrStrt, yrLast, "integer")
>>>>>>> yrfrac = (/ yyyymm_to_yyyyfrac(yyyymm, 0.0) /)
>>>>>>>
>>>>>>> --Mary
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Wed, Nov 28, 2018 at 1:05 PM Soma Roy <somaroy892 at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Thank you very much for the hint.
>>>>>>>> I will check it.
>>>>>>>>
>>>>>>>> But mannualy we can't set the "date" range in the script without
>>>>>>>> using CDO?
>>>>>>>>
>>>>>>>> Please kindly inform me.
>>>>>>>>
>>>>>>>> Thanking you,
>>>>>>>> Soma
>>>>>>>>
>>>>>>>>
>>>>>>>> On Thu, Nov 29, 2018, 01:28 Guilherme Martins <jgmsantos at gmail.com
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> I don't know if you use climate data operators or cdo software.
>>>>>>>>>
>>>>>>>>> You can set the data in your file.
>>>>>>>>>
>>>>>>>>> Exemple
>>>>>>>>>
>>>>>>>>> cdo settaxis,1970-01-01,00:00:00,1mon input.nc output.nc
>>>>>>>>>
>>>>>>>>> Guilherme.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Em qua, 28 de nov de 2018 16:35, Soma Roy <somaroy892 at gmail.com
>>>>>>>>> escreveu:
>>>>>>>>>
>>>>>>>>>> Hello,
>>>>>>>>>>
>>>>>>>>>> I am trying to calculate standadize precipitation index using
>>>>>>>>>> monthly gridded dataset.
>>>>>>>>>>
>>>>>>>>>> Dimension of data is like below;
>>>>>>>>>> Rainfall(12x41) (months x years).
>>>>>>>>>>
>>>>>>>>>> I am using the script from the below link;
>>>>>>>>>> https://www.ncl.ucar.edu/Applications/Scripts/spi_2.ncl
>>>>>>>>>>
>>>>>>>>>> But in my dataset there is no variable as "date".
>>>>>>>>>>
>>>>>>>>>> Can we manually set the date range inside the script?
>>>>>>>>>>
>>>>>>>>>> I am using rainfall dataset for 1970-2010.
>>>>>>>>>>
>>>>>>>>>> Please kindly inform me how we can modify it over the same script.
>>>>>>>>>>
>>>>>>>>>> Thanking you,
>>>>>>>>>> Soma
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