Seasonal and interannual changes of significant wave height in shelf seas around India during 1998–2012 based on wave hindcast

Abstract

Present study examines the interannual changes of significant wave height (Hs) in shelf seas around Indian mainland based on the 15-year (1998–2012) wave hindcast data obtained from numerical model. Validation of the hindcast data with buoy-measured data shows that hindcast Hs is reasonably in good agreement with the observation (Pearson correlation coefficient values of 0.92–0.97). Annual average Hs varied from 0.9 to 1.4 m and the wave heights are higher (∼20%) in western shelf seas compared to eastern shelf seas. The analysis reveals seasonal fluctuations of wave climate, with a strong influence of Asian summer monsoon in the western shelf seas compared to the eastern shelf seas of India. Maximum Hs varied from 3.65 to 7.36 m and these maximum values were during the tropical cyclones. During 1998 to 2012, a statistically significant positive trend of 0.8–1.4 cm yr−1 in annual mean Hs is observed and the increasing trend is higher (∼0.7–2.5 cm yr−1) during the Asian summer monsoon period (June–September). The average trend of annual mean wind speed is also positive and is higher (∼1.67 cm s−1 yr−1) for the western shelf seas than that for eastern shelf seas (∼0.93 cm s−1 yr−1).