Correlations between fitted impedance and water content for channels and rib regions are also calculated (as shown in Fig. ) to assess whether EIS can predict water content in the channels. The correlation between channels and impedance is almost identical to that with overall water content, while the correlation between rib regions' water content and impedance is weak. This may be attributed to the fact that introducing water directly or switching to dry gas initially changes the water content in the channel region, as diffusion of water to the rib region requires additional time.