CDO

Hello,

I am trying to calculate the ETCCDI climate extreme indices on CMIP climate model output data for both the historical period and future (scenarios) using CDOs. I have successfully calculated most of the indices using CDO's etccdi_* commands , however, I am struggling to calculate percentile-based indices such as TX90p for the future data.

As far as I understand, in the CDO etccdi_tx90p command, I must provide the start and end of the bootstrapping period as parameters, as well as the running daily min and max as additional infiles along with the daily tasmax data on which I want to calculate the index. This works perfectly for the historical period, since the input data spans 1850-2014 and the bootstrapping period is 1961-1990. However, when calculating TX90p for future scenarios, I want to use the same thresholds as calculated for the historical period rather than defining a new bootstrapping period for the future data. When I try to run this by running the command:
cdo etccdi_tx90p,5,1961,1990,m input_daily_tasmax_2015-2100.nc input_daily_tasmax_min_1961-1990.nc input_daily_tasmax_max_1961-1990.nc output.nc
I get the error "The interval start year '1961' is before infile start year '2015'.

How can I solve this error? For the future scenario, bootstrapping isn't needed since the base period does not lie in the data, but I cannot figure out how to make this work using CDOs. One thought is to first merge the historical and scenario data and then run the etccdi_tx90p command and then split the output.