Numerical Simulation of Wave Characteristics off Kulasekharapatnam, Southeast Coast of India

Abstract

Waves are important driving forces that have significant implications in deep and shallow waters. To achieve further understanding of the characteristics of wind waves in the Gulf of Mannar, an attempt is made based on the measured data off Kulasekharapatnam for the period from January 2006 to May 2007. The integrated third-generation ocean wave models, WAM and SWAN, are implemented to simulate the significant wave parameters. Simulations were carried out using ECMWF ERA-Interim winds over the deep waters (30°E–120°E; 70°S–30°N and 76°E–80°E; 6°N–10°N) domains. Comparison of the ECMWF ERA-Interim wind data against the field measured data demonstrates that the overall trend and dominant directions are consistent with the observational data. The validation of significant wave parameters exhibited very high correlation (R > 0.9) at the study location. Wave heights are high in the Gulf of Mannar during the southwest monsoon period and the waves are from south-southwest. The study also shows that swells are predominant (24%) in the Gulf of Mannar during non-monsoon period and during rest of the year, wind sea (75.9%) dominates. The study also demonstrates the sensitivity of the SWAN model towards different GEN3 physics options and bottom friction formulations by forcing the model with QuikSCAT/NCEP Blended winds off Kulasekharapatnam. The simulations obtained using different GEN3 physics options and bottom friction formulations have been compared with the buoy data. The study indicates that the SWAN model with Janssen and Komen physics options simulates the significant wave height and mean wave period, respectively, with a fairly high degree of accuracy. Similarly, the JONSWAP formulation for bottom friction reproduced the buoy signals at the study location with good accuracy for both significant wave height and mean wave period. The study demonstrates that the simulations are sensitive to the choice of GEN3 physics and bottom friction formulations off Kulasekharapatnam, and hence effective for obtaining more accurate wave predictions.