Cold days percent wrt 10th percentile of reference period
ecatg10p.RdLet infile1 be a time series of the daily mean temperature TG, and infile2 be the 10th percentile TGn10 of daily mean temperatures for any period used as reference. Then the percentage of time where TG < TGn10 is calculated. TGn10 is calculated as the 10th percentile of daily mean temperatures of a five day window centred on each calendar day of a given climate reference period. Note that both TG and TGn10 have to be given in the same units. The date information of a timestep in outfile is the date of the last contributing timestep in infile1.