Prediction of Uncertainty Using the Third Generation Wave Model WAVEWATCH III Driven By ERA-40 and Blended Winds in the North Indian Ocean

Abstract

Simulation of waves in North Indian Ocean using ERA-40 and QuikSCAT/NCEP blended winds over 1° × 1° grid resolutions has been realised globally as well regionally using the third-generation wave model WAVEWATCH III (WWIII). Moreover, the model performance was evaluated by quantifying the uncertainty`s. So, WWIII simulations have been carried out for the North Indian Ocean from 50°E to 100°E and 0°N to 30°N with the past analysed winds (hindcasting) and the boundary conditions from the global run. The model outputs such as significant wave height (Hs) and mean wave period (Tc) are compared with the buoy measurements. To assess the performance, various statistical errors have been estimated by validating the model results against moored buoy data in the Arabian Sea and Bay of Bengal. The validation of WWIII with buoy measurements gave promising results for the North Indian Ocean with Model Performance Index ranging from 0.86 to 0.99, irrespective of the input winds. Also, Percentage Error ranges from 3.1 to 18.8% for the selected periods (January, July and October) except April. Further, the model was examined with different wind forcing’s and the study revealed better performances with blended winds, which could accurately predict Hs and Tc at buoy locations. This study concludes that, WWIII model predicts the sea-state evolution with acceptable uncertainty, which is reliable for the Indian Seas (North Indian Ocean) using the analysed wind fields. Further, better accuracy is achieved using blended wind products.