Observed tides at Mumbai High offshore region near the continental shelf break in the eastern Arabian Sea

The observed large tidal range (up to 3 m during spring tide) at the Mumbai High offshore region located near the continental shelf break, off the central west coast of India, is described based on simultaneous tidal measurements (30 s average) at 15 min sampling interval using four tide gauges deployed from an oil drilling platform of the Oil and Natural Gas Corporation of India. All the four gauges provided identical measurements. The measured tides were harmonically analysed and the amplitudes and phases of the five major constituents, i.e. M 2 , S 2 , K 1 , O 1 and N 2 were compared with those observed at the closest coastal station (Apollo Bandar, Mumbai). It was found that the observed tidal range at this offshore location was unusually larger than those found in the open-ocean regions. This large tidal range was found to be associated with the large width of the continental shelf off the central west coast of India.