[ncl-talk] How to combine many separate nc files together and convert them to monthly?

[Setareh Rahimi]

Dear all,

I have downloaded the Normalized Difference Vegetation Index (NDVI), from
the Advanced Very High-Resolution Radiometer (AVHRR) sensor from the link
below:
https://www.ncei.noaa.gov/metadata/geoportal/rest/metadata/item/gov.noaa.ncdc:C01558/html

As you can see this link provides daily data. And I have downloaded daily
data from 1986 to 2021. I put the daily data for each year in a separate
folder.
Now I tend to calculate the monthly anomaly of NDVI and do not know how to
combine all these files.

I used the below commands to call the files:
========================================
fils = systemfunc("ls [1-2][8-9-0-1]*/*nc")
   print(fils)

   f   = addfiles (fils, "r")

   x   = short2flt(f[:]->NDVI)

   printVarSummary(x)
=========================================
but got the attached error! Please have a look at the attached screenshot.
How can I combine all those files together, please?
I really appreciate any help you can provide.
Best wishes,

-- 
S.Rahimi
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.ucar.edu/pipermail/ncl-talk/attachments/20220628/4b9637de/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Screen Shot 1401-04-07 at 8.47.47 PM.png
Type: image/png
Size: 187042 bytes
Desc: not available
URL: <https://mailman.ucar.edu/pipermail/ncl-talk/attachments/20220628/4b9637de/attachment.png>