About percetile with 5 day window

Hello everyone,

I am trying to compute "when a JJA daily temperature (1980–2018: "Daily_temp_1980–2018.nc") exceeds its 90th percentile. The calendar-
day percentiles is computed using a fixed climatological period (1981–2010: "Daily_temp_1981–2010.nc") with a 5-day window centered on each calendar day."

I did the following"

#-- compute the 90th percentile for 1981–2010 with a 5-day window centered on each calendar day.

cdo -timselmin,5 Daily_temp_1981–2010.nc minout.nc
cdo -timselmax,5 Daily_temp_1981–2010.nc maxout.nc
cdo -timselpctl,90,5 Daily_temp_1981–2010.nc minout.nc maxout.nc Temp_90percentile.nc

when daily 1980–2018 temperature exceed the 90th percentile
cdo gt Daily_temp_1980-2018.nc Temp_90percentile.nc output.nc

But I get this error: "cdo gt (Abort): Input streams have different number of timesteps!"

Truly the two datasets have different timesteps" "Daily_temp_1980-2018.nc" has 3,582 timesteps and "Temp_90percentile.nc" has 570 timesteps.

Please, how do I resolve this problem?

By the way,I have used this code: "cdo -timpctl,90 Daily_temp_1981–2010.nc -timselmin,5 Daily_temp_1981–2010.nc -timselmax,5 Daily_temp_1981–2010.nc Temp_90percentile.nc," which outputs a single timestep, but I don't think my result is accurate using "timpctl" instead of timselpctl."

I have attached my dataset and would appreciate your assistance.

Thank you.

Download all files

Daily_temp_1980–2018.nc (65.3 MB) Daily_temp_1980–2018.nc	JJA Daily_temp_1980–2018
Daily_temp_1981–2010.nc (51.9 MB) Daily_temp_1981–2010.nc	JJA Daily_temp_1981–2010

Replies (3)

RE: About percetile with 5 day window - Added by Karin Meier-Fleischer 9 months ago

Hi Michael,

the dates 1988-08-15 to 1988-08-20 are missing in the file Daily_temp_1980–2018.nc. This will always cause an error or warning. Please, upload a correct file otherwise we can't help.

RE: About percetile with 5 day window - Added by Karin Meier-Fleischer 9 months ago

The file names have long hyphens, which is unusual in the Linux world. It took me a while to figure out why I was getting a 'file not found' message.

But nevertheless I think you are looking for something like this:

cdo -ydrunpctl,90,5 Daily_temp_1981–2010.nc \
    -ydrunmin,5 Daily_temp_1981–2010.nc \
    -ydrunmax,5 Daily_temp_1981–2010.nc \
     Temp_90percentile.nc

cdo -gtc,0 -sub Daily_temp_1980–2018.nc Temp_90percentile.nc output.nc

RE: About percetile with 5 day window - Added by Michael Akin 9 months ago

Thank you so much Karin, I appreciate it.

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