Assessment of the forecasting potential of WAVEWATCH III model under different Indian Ocean wave conditions

This study assesses the performance of different source term packages of WAVEWATCH III (WWIII, V-6.07) wave model for various wave conditions in the Indian Ocean (IO). Eight simulations of WWIII were made for the year 2017, four using default source term packages (ST2, ST3, ST4, and ST6) and another four by tuning the wind–wave interaction parameter ( β ) in the ST4 and ST6 schemes. The simulated wave outputs are compared with in-situ and altimeter wave fields over a wide range of weather conditions. All wave simulations have significant errors in low wind speeds (e.g., in pre-monsoon season) compared to medium (e.g., post-monsoon) and strong (e.g., monsoon season) winds which is independent of the error in the forecast wind. Overall, the ST4 scheme reproduces well the wave characteristics in all seasons and different conditions of IO, while the ST6 scheme is best suited for cyclonic weather conditions for wave simulation. Changing the WWIII parameterization schemes based on wind conditions is not a practical option for a timely wave prediction for a basin like the IO, where varied wave patterns exist year-round, owing to the full spectrum of wind conditions. Instead, this study advocates selecting a scheme that works well in all conditions, like ST4, and tuning it to suit well in cyclonic conditions.