Fig. 5

Calculation results of \({W}_{\mathrm{int}}\) and \({\zeta }\) distribution. (top) Time variation of \(W_\mathrm{int}\). The solid line indicates the \(W_\mathrm{int}\) and the dashed lines indicate \(W_\mathrm{int} \pm 1.96 \sigma _\mathrm{w}\). (bottom) \(\zeta\) distribution. a Calculation results using the algorithm of the S-WPIA. b Simulation results from Figs. 4a and 5a in Katoh et al. (2013)