Changes in nearshore waves during the active sea/land breeze period off Vengurla, central west coast of India

Abstract

A unique feature observed in the tropical and subtropical coastal area is the diurnal sea-breeze/land-breeze cycle. We examined the nearshore waves at 5 and 15m water depth during the active sea/land breeze period (January-April) in the year 2015 based on the data measured using the waverider buoys moored in the eastern Arabian sea off Vengurla, central west coast of India. Temporal variability of diurnal wave response is examined. Numerical model Delft3D is used to study the nearshore wave transformation. The wave height increased due to the sea breeze and reached its peak at ∼13:00 UTC at 15m water depth, whereas the peak significant wave height is at 12:00 UTC at 5m water depth. Due to the influence of the land/sea breeze system, the range of the peak wave period in 1 day varied up to 8 s. Reduction in the wave height of wind-sea is around 20% and that of the swell is around 10% from 15 to 5m water depth.