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Calculation of TX90 indice

Added by patty Lyn over 2 years ago

Hi, I am trying to compute the extreme index TX90, according to the guidance, it should be eca tx10p infile1 infile2 outfile， the infile2 is the TXn90 is calculated as the 90th percentile of daily maximum temperatures of a five day window centred on each calendar day of a given climate reference period.

May I ask, if we can calculate the TXn90 using CDO as well?


Replies (5)

RE: Calculation of TX90 indice - Added by dax koch over 2 years ago

I have found these two topics that asked the same question but still not found the answer https://code.mpimet.mpg.de/boards/2/topics/4874 https://code.mpimet.mpg.de/boards/1/topics/1098

RE: Calculation of TX90 indice - Added by Karin Meier-Fleischer over 2 years ago

Hi Patty and Dax,

maybe you should have a look at the ECA indices (Climate indices with CDO) especially the operator eca_tg90p (see https://code.mpimet.mpg.de/projects/cdo/embedded/cdo_eca.pdf).

-Karin

RE: Calculation of TX90 indice - Added by patty Lyn over 2 years ago

Dear Karin, thank you. Still, for the eca_tg90p, they only give the details that how the TGn90 is computed(the method), but we have to compute the 90th file on our own. So my question remains: can we compute the 90th of TG using CDO?

RE: Calculation of TX90 indice - Added by Karin Meier-Fleischer over 2 years ago

Sorry, but I'm not an expert on this. Maybe the others could help?

RE: Calculation of TX90 indice - Added by Benny Istanto over 2 years ago

Hi, maybe a bit late for the answer.

My best guess on how to calculate the 90th percentile of daily max temperature of a five windows centred is using YDRUNPCTL operator.

To compute the running multi-year daily 90th percentile over all input timesteps for a running window of five days use:

cdo ydrunmin,5 infile minfile 
  cdo ydrunmax,5 infile maxfile 
  cdo ydrunpctl,90,5 infile minfile maxfile outfile

Or shorter using operator piping:

cdo ydrunpctl,90,5 infile -ydrunmin infile -ydrunmax infile outfile

I have tested using above, and it worked. I used daily tasmax from CHELSA, 1979-2016.
As a note, I did some data manipulation before using YDRUNPCTL:
- Convert Kelvin to degC (including change the variable units too from "K" to "degC")
- Merge all the input into single nc using mergetime
- Delete data who has 29th February using -delete,month=2,day=29 or del29feb operator

Hope it help.

Best,
Benny

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