Spatial and temporal variations of wave height in shelf seas around India

The spatial and temporal variations of wave height in shelf seas around Indian mainland are examined based on the ERA-Interim dataset produced by the European Centre for Medium-Range Weather Forecasts. The study shows that during the summer monsoon, higher wave heights are observed in all locations except at the southern locations in the shelf seas around India, where the winter monsoon is predominant. The annual average significant wave height is highest (~1.6 m) at the southern location. During 1979–2012, a weak statistically significant increasing trend (maximum ~0.20 cm/year) in wave height is observed in the northern and southern region of eastern Arabian Sea, whereas the middle region shows negligible negative trend. A weak decreasing trend (maximum ~−0.18 cm/year) in wave height is observed in the western Bay of Bengal except along the southern region. At most of the locations weak decreasing trend (0.1–2.5 cm/s/year) is observed for the annual mean wind speed. The conflicting trends in the wind speed and wave height are mainly due to the swell dominance in the North Indian Ocean.