[ncl-talk] Percentile

[Adam Phillips]

Hi Soma,
You can use qsort:
https://www.ncl.ucar.edu/Document/Functions/Built-in/qsort.shtml
Note that qsort only accepts a single dimension, so you'll have to call
qsort for each lat/lon point individually:
; untested
arr95 = prc(0,:,:)
arr95 = arr95 at _FillValue
arr5 = arr95
ntime = dimsizes(prc&time)
i5 = toint(ntime*.05)-1    ; approximate 5% index
i95 = toint(ntime*.95)-1  ; approximate 95% index
do gg = 0,dimsizes(prc&lat)-1
    do hh = 0,dimsizes(prc&lon)-1
        temp = prc(:,gg,hh)
        qsort(temp)
        arr5(gg,hh) = temp(i5)
        arr95(gg,hh) = temp(i95)
        delete(temp)
    end do
end do

As always with any donated script on ncl-talk, make sure you understand
what is happening in the script by using print statements and
printVarSummary, and verify that the script is doing what you think it
should be doing.
If you have any further questions about ncl please respond to ncl-talk.
Adam


On Wed, Dec 5, 2018 at 12:49 PM Soma Roy <somaroy892 at gmail.com> wrote:

> Hello,
>
> I want to compute rainfall (gridded) values greater than 95th percentile
> and less than 10th percentile.
>
> printVarSummary of the input data is as follows;
> Variable: prc
> Type: double
> ..[snip]
> Dimensions and sizes:   [time 14965| ] x [lat | 129] x [lon | 135]
> [snip]
> ......
>   _FillValue :  -999
>   long_name :   GRIDDED RAINFALL
>   missing_value :       -999
>
> Please kindly suggest me a suitable way to execute it.
> I would like to get my output results over latitude-longitude.
>
> Thank you,
> Soma
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-- 
Adam Phillips
Associate Scientist,  Climate and Global Dynamics Laboratory, NCAR
www.cgd.ucar.edu/staff/asphilli/   303-497-1726

<http://www.cgd.ucar.edu/staff/asphilli>
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