# [ncl-talk] Computing max of monthly NO2 data each year

Doumbia thiernodoumbia at yahoo.fr
Tue Sep 29 10:22:58 MDT 2015

```I add some thing in your code and it gives me the good results.
yr = i would be yr = i+1.

The new script is:
do n=0,7
yr=0
k =0
do i = 11,275,12
EUmax(n,k) = max(EU_plot(n,yr:i))
k=k+1
yr=i+1
end do
end do

Jack, thank again.
Thierno

> Le 29 Sep 2015 à 18:02, Doumbia <thiernodoumbia at yahoo.fr> a écrit :
>
> Hi Jack,
> I really appreciate your teaching skills.
>
> I recognize that there’s weird things in my script but I apologize for that, I am new in NCL.
>
> Unfortunately, your suggestions don’t give the good results i.e. the maximum of monthly NO2 data for each year. I compared these results with those obtained from excel.
>
> You are right, the "EU(120:395,0)” is for 1990 to 2012 (23 years).
>
> Thank you for your help.
>
> Thierno
>
>
>>
>> ...
>> “The results I’ve obtained aren’t what I expected.”
>> ...
>> Well, even Aristotle would struggle to figure out what you expected if you didn't tell him…
>>
>> Your script still got visible mistakes though. For example the loop is quite extravagant:
>> …
>> k = ispan(0,11,1)
>> do n=0,7
>>  do i = 0,275,12
>>   do j=0,11
>>     EUmax(n,:) = max(EU_plot(n,i+k(j))) <== “j” will always be the same type as, and equal to “k(j)”?
>>   end do
>>  end do
>> end do
>> …
>> and since the left side of your equation has a free dimension, the variable will always be overwritten up to the end of the loop.
>>
>> You can clean the loop and do something like,
>> do n=0,7
>>    yr=0
>>    k =0
>>    do i = 11,275,12
>>       EUmax(n,k) = max(EU_plot(n,yr:i))
>>       k=k+1
>>       yr=i
>>    end do
>> end do
>>
>> I was also wondering whether from your file “EU(120:395,0)” will give you information from 2000 to 2012(12 years)? Probably that is the unexpected result you mentioned. Who knows?
>>
>> I hope that helps.
>>
>> Jack
>>
>>> On 29 Sep 2015, at 15:02, Doumbia <thiernodoumbia at yahoo.fr> wrote:
>>>
>>> Dear ncl users,
>>>
>>> I am trying to compute the monthly maximum NO2 in a yearly basis.
>>>
>>> My input file contains 7 columns representing different variables and 396 lines (monthly mean NO2 data from 1980 to 2012). I am only interested by the 2000-2012 period .
>>>
>>> The results I’ve obtained aren’t what I expected.
>>> <max_of_monthly_data.ncl><Europe_bis_ncl.txt>
>>> I will appreciate any help to resolve this.
>>>
>>> Please find attached my script as well as my input file.
>>>
>>> Thierno
>>>
>>> _______________________________________________
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>>> ncl-talk at ucar.edu
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>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>
>

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