Waves in shallow water off west coast of India during the onset of summer monsoon

Abstract. The wave growth characteristics during the onset of summer monsoon in a swell dominated open ocean at a location off the west coast of India at 14 m water depth are studied. 67% of the measured waves are due to the swells arriving from south and south-west and the balance was due to the seas from south-west to north-west. Wave age of the measured data indicates that the measured waves are young sea with presence of swells. Even when the wind speed reduced to less than 3 m/s, significant wave height more than 2 m is present due to the swells in the Arabian Sea. The maximum wave height increased from 2 to 8 m within 60 h. The mean wave directions at the high frequencies align with the westerly wind direction and gradually shift to south-westerly swell direction at low frequencies during the wave growth. The strong westerly winds present between longitude 72° and 72.5° at latitude 12.5° has created the high waves (H_m0 upto 5.65 m) during the measurement period.