Fig. 3

The ACF and PACF graphs for estimating the parameter. a The ACF graph of the raw data (d = 0 and D = 0); b the PACF graph of the raw data (d = 0 and D = 0); c the ACF graph of one-order trend difference data (d = 1 and D = 0); d the PACF graph of one-order trend difference data (d = 1 and D = 0); e the ACF graph of one-order seasonal difference data (d = 1 and D = 1); f the PACF graph of one-order seasonal difference data (d = 1 and D = 1)