Table 1 shows that the estimated resolution of the IER sequence for Blind Beck is around 9–10 time periods (i.e., 2.25–2.5 h) and for Baru it is 11–12 time periods (i.e., 55 min–1 hr). Both estimates are within the N–S safe sampling limit and below the fast time constant for both catchments indicating that even though resolution has been lost – the regularisation trade-off for numerical stability – the dominant mode of the rainfall–streamflow dynamics has been captured. Table 2 shows that the estimated resolution of the IER for both catchments is well within the Nyquist limit and, while the Blind Beck resolution is within the safe limits suggested by Ljung (1999) and Young (2010), the estimated resolution for Baru is close to the fast TC and outside the suggested limits. The estimates of resolution of the inferred sequence made from the aggregation plots are not always well defined and may be dependent on the length of record which will affect the number of aggregation periods that may be meaningfully calculated given the finite length of the data series. A better means of estimation of resolution may be achieved by examining the frequency spectra of the rainfall and streamflow sequences.

Table 2

The estimated resolution of the IER compared to the TCq, Nyquist limit and safe sampling limits suggested by Ljung (1999) and Young (2010)

CatchmentTCq (hours)Nyquist limit (hr)Ljung interval (hr)Young interval (hr)Estimated resolution (hr)
Blind Beck 6.3 19.9 3.98 3.32 2.25–2.5
Baru 1.1 3.4 0.68 0.57 0.91–1.0
CatchmentTCq (hours)Nyquist limit (hr)Ljung interval (hr)Young interval (hr)Estimated resolution (hr)
Blind Beck 6.3 19.9 3.98 3.32 2.25–2.5
Baru 1.1 3.4 0.68 0.57 0.91–1.0

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