which is analogous to transient conduction of a heat impulse in an insulated domain and can be found for example in textbooks of heat transfer . Previously published tracer curves were reconstructed with the proposed dispersion model (eq 3) by fitting the dispersion coefficient to the experimentally determined local mixing times (95 % homogeneity or equivalently 5 % deviation relative to equilibrium at the measurement location). The reported tracer data points were obtained from the published figures with WebPlotDigitizer . The series in eq 3 was approximated with 20 terms.