Peak correlation r_p between am and 3-hourly means of P_α/P_o as a function of the logarithm of the lag dt_p giving that peak correlation, for data from 1995–2017, inclusive. One-minute P_α/P_o data were averaged into hourly and then 3-hourly intervals, centred on the mid-points of the am data intervals, minus a response lag dt that was varied between −10 min and 5 h in steps of one minute. At each dt the correlation between P_α(t − dt)/P_o and am(t) is evaluated for each of the data subsets studied. The data are divided and colour-coded into 9 quantile ranges of am given by the legend. We use the notation that 20% of all the data have am values lower than q(0.2). The red dots are for all data, q(0) < am ≤ q(1). Five of the quantile ranges each contain 20% of the data: q(0) < am ≤ q(0.2), q(0.2) < am ≤ q(0.4), q(0.4) < am ≤ q(0.6), q(0.6) < am ≤ q(0.8) and q(0.8) < am ≤ q(1). In addition, the plot studies the top 10%, 5% and 1% of all am values, respectively q(0.9) < am ≤ q(1), q(0.95) < am ≤ q(1), and q(0.99) < am ≤ q(1). Correlations are shown for F–UT–m bins that have more than 16 samples and for which the correlation significance exceeds 95%.