The [index] section of a configuration file contains options used to determine the start and end years of climate indices (such as El Niño 3.4):

## options related to producing nino index.

# start and end years for El Nino 3.4 analysis. Use endYear = end to indicate
# that the full range of the data should be used.  If errorOnMissing = False,
# the start and end year will be clipped to the valid range.  Otherwise, out
# of bounds values will lead to an error.  In a "control" config file used in
# a "main vs. control" analysis run, the range of years must be valid and
# cannot include "end" because the original data may not be available.
startYear = 1
endYear = end

Start and End Year

A custom config file should specify a start and end year for time axis. If errorOnMissing = False in the input section and the start or end year is beyond the range of the simulation, the range will be reduced to those dates with available data and a warning message will be displayed. If errorOnMissing = True, out of range year will produce an error.