Wave Prediction for the east coast of India under storm conditions in the Bay of Bengal

Abstract

Cyclonic storms are frequent in the Bay of Bengal particularly during the NE monsoon period. Some of these storms are severe and generate high waves which cause havoc in the coastal regions. This paper presents an analysis of the cyclonic storm which hit coastal Andhra Pradesh on 7 November 1969.

Wave prediction under storm conditions involves an analysis of moving fetches and variable wind speeds. Wilson's graphical method incorporating the latest available wave prediction relations was used for wave predicted waves which are deep water waves, were modified to account for refraction, shoaling and bottom friction effects as they enter shallower waters. The predicted waves were compared with the waves observed by the Visakhapatnam outer harbour authorities.

The results of the analysis suggest that (i) Wilson's graphical method can be applied for wave prediction for Indian coasts under storm conditions, (ii) the recommended value of bottom friction factor appears to be low and (iii) waves of considerable height are experienced even in areas not in the direct path of the cyclone.