[ncl-talk] SPI calculation
Soma Roy
somaroy892 at gmail.com
Thu Nov 29 01:15:01 MST 2018
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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