Comparison of nonlinear energy transfer rate estimates obtained as the average LPDE $({\overline{\epsilon }}_{{}_{\mathrm{LPDE}}})$, isotropic maximum absolute value (|ε_iso|^max, panel a), and average isotropic value (${\overline{\epsilon }}_{{}_{\mathrm{iso}}}$, panel b). The former is averaged over all LPDE estimates. The latter two are obtained within the shaded green areas that are roughly representative of the inertial range in Fig. 8. The error bars represent the standard deviation about the means.