Impact of Climate Modes on Shoreline Evolution: Southwest Coast of India

Coastal geomorphology is a complex phenomenon which is governed by nearshore wave and tidal climate. Change in climate indices (like sea surface temperature, sea level, intensified cyclone activity, among others) and climate modes (like El Nino Southern Oscillation (ENSO), Southern Annular Mode (SAM), Indian Ocean Dipole (IOD)) affect the wave climate and modify many coastal processes thereby altering the geomorphology of shorelines. In countries like India where tropical and sub-tropical cyclones are common, the coastal geomorphology is under constant threat. Coasts are also vulnerable to anthropogenic factors like offshore structures, harbours, wave farms and other constructional activities along the shoreline. It is thus necessary to understand the evolution of coastlines under the changing climate scenario. The rapidly growing socio-economic development in south-west coast of India has generated the need to investigate the longshore sediment transport (LST) regime in this region under the influence of variable climate factors like the wave characteristics. The presence of numerous river deltas, estuaries and mud banks makes the situation worse especially during the south-west monsoon season (June-September). The investigation on the contemporary evolution of this coastline has not been undertaken and the knowledge of the climate factors that influence the shorelines of the southern tip of India are unknown. This study attempts to understand the temporal dynamics of the longshore sediment transport in this region.