Amplified Msf tides at Kochi backwaters on the southwest coast of India

Abstract

Characteristics of tides at eight stations in Kochi backwaters (KB) located on the southwest coast of India are analysed. The Msf tidal constituents at several locations are found to be considerably larger than those estimated from the driving tidal potential. The Msf tidal amplitude amplifies progressively from Kochi inlet to the shallower upstream region where it exhibits approx. 3 - fold amplification. At the upstream boundary, the Msf tide has the same order of magnitude as M sub(2) and K sub(1) tides. The nonlinear frictional interaction between M sub(2) and S sub(2) tides appears to be mainly responsible for the observed amplification. However, in regions where depth is less than 2 m, variable bottom frictional effects at fortnightly periodicity plays an additional role in the Msf tidal amplification.