Adoption of continuous wavelet and recurrence plots to comparative studies of neutron monitor data sets (1975 – 2018)
2019 July 26
The hourly pressure corrected data of individual neutron monitor station (NM) collected in WDC, from seventies of XX century to nowadays, are compared with records of other stations with similar cut-off rigidity in order to determine the quality of the studied data. Taking no account some short time details as GLE events, one can expect a similar NM intensity response at stations, with the similar cut-off rigidity, to the solar variability on moderate and long time scales. It could be reflected by similar values of the Pearson correlation coefficients and slopes of regression lines between the smoothed solar activity indices and NM data. The solar activity is represented by Ottawa/Penticon radio flux. If the correlation coefficients considerably wander away from the mean value for the determined epoch the data registered at such station in this time period should not be used to a further study of long-term variations. Powerful wavelet technique can also is applied to test the data in time - frequency space.We provide such analysis for two sets of data with high and moderate cut-off rigidities. Periods with data gaps or with inconsistency of records ought to be corrected before further elaboration by means of the neuron network (NN) reconstructions. We propose the Elman NN as possibly the best available method for such correction. The results are presented in tables and on wavelet plots. Stations which have showed considerably different variations at some periods than other are indicated.