Line 8: Time interval between measurement start points.
The interval between consecutive measurement start points is stated in
the same units as the file time axis, (fractional) days. For hourly
averaged data, it is 1/24 = 0.041667, for 3-hourly data 0.125, and for
daily averaged data, it is 1. Stating this interval implies that it
applies for the whole data section of the file. Shifts in time need to
be corrected, holes in the time series need to be filled with missing
data tags, and the data needs to be aggregated to averages as required
by the observation type. Please use a precision of at least 6 digits
right of the decimal point.