Wind-wave measurements and modelling in the shallow semi-enclosed Palk Bay

Abstract

Wind-wave characteristics of the Palk Bay, a semi-enclosed water body, are studied by the wave measurements carried out at 2 locations during a one-year period. The analysis of wave data sets shows that wind-sea dominates the Palk Bay during 96% of the time and the contribution of swells are insignificant (<4%). In the Palk Bay, wind speeds are low and act on a limited fetch of only a few kilometers and thus cause waves with small amplitudes, short-wave periods, and short wavelengths. In an annual cycle, significant wave height varied from 0.2 to 1.9 m with an average of 0.6 m. The mean wave periods are mostly concentrated in a narrow range (2-4 s) with a large proportion (~48%) of the waves with a mean wave period less than 3 s. In the southern part of the Palk Bay, northerly waves are more energetic compared to the southerly waves. The wave hindcast data reproduce significant wave height with reasonable accuracy, with a positive bias of 0.08 m, root mean square error of 0.3 m and scatter index of 0.5 when the forcing winds are from Weather Research and Forecast (WRF) numerical model.