Fig. 8

The time series of the normalized voltage corresponding to Fig. 7. The amplitude variation with time is the “fading” analyzed in the original SA technique. The mean fading time for the record is shown in the panel on the right hand side. In any cross-correlation analysis, data records need to be of sufficient length to characterize the correlation functions. Because of this, the QC parameters applied to these types of analysis (see, e.g., Table 6) reject records for “slow fading”, and indicators of poor correlation function form. Ideally, the record length should be selected based on the fading characteristics at a particular height. This would be simple to implement on current systems