Tides in the Gulf of Kutch, India

In the Gulf of Kutch on the northwestern shelf of India the semi-diurnal constituents M2 and S2 get amplified approximately threefold. In contrast, amplification of the diurnal constituents K1 and O1 is small. From analytical and numerical solutions of linear, viscous, cross-sectionally averaged equations for tidal motion in a channel, it is seen that the observed amplification results from a combination of quarter-wavelength resonance, geometric effect due to decrease in width of the channel, and friction.