Propagation of tides in the Cochin estuarine system, southwest coast of India

Analysis of hourly data on sea level collected at four stations in the Cochin estuarine system has been made to understand the tidal and non-tidal sea level variations inside the estuary, for spring and neap phases during March 2000. Spring phase was dominated by semi-diurnal tides whereas neap phase was dominated by diurnal tides. Diurnal and semi-diurnal bands were together responsible for a high percentage of variance of the observed sea level. The dominance of shallow water tides was seen with increasing distance from the mouth. The sea level variance was dominated mainly by tidal signals, but the tidal influence decreased rapidly inside the estuary. Doodson's X o filter appears to be efficient for de-tiding the observed sea level time series.