Comparison of Hind-Cast Wave with Measured Wave Off Puducherry Coast, Eastcoast of India

Abstract

In the present study, the available hind-cast wave data off Puducherry coast in deep water are transformed to 15 m water depth using linear wave theory and compared with the wave data measured by Indian National Centre for Ocean Information Services (INCOIS), Hyderabad, in 15 m water depth off Puducherry coast. The correlation analysis, comparison of annual wave rose plot and scatter analysis are carried out for both the wave data at 15 m water depth. Based on correlation analysis, it can be seen that wave height and wave direction, the cross-covariance are high for both wave data. But for wave period, cross-covariance coefficient is significantly low. From the wave rose plot, it can be seen that incase of hind-cast data, predominantly waves coming from northeast direction (60°N to 150°N) with the maximum wave height in the range of 0.5 to 2.0 m. Where as measured data, predominantly waves coming from southeast direction (90°N to 150°N) with maximum wave height in the range of 0.5 to 1.5 m. From the scatter analysis of both the wave data, it is observed that the incase of hind-cast wave, 33% of the time wave approaching angle is less than 90°N where as measured wave it is 12% of the time. In case of hind-cast wave data, the number of event with wave height more than 1 m is around 976 (33.4 %) whereas in case of measured wave, it is around 500 (17%) i.e. nearly half. The changes in the basic data on wave height, wave period and wave direction which will significantly influence in the estimation of littoral drift along the coast. It is however suggested to use the measured wave data for the estimation of sediment transport in order to arrive at more dependable values on littoral drift.