Performance of ERA-Interim Wave Data in the Nearshore Waters around India

Abstract

ulk wave parameters, such as wave height and wave period, are required for engineering and environmental applications. In this study, measured wave data from six shallow-water locations in the data-sparse north Indian Ocean are used to assess the Interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis [ERA-Interim (ERA-I)] wave height and period data in the nearshore waters around India. The difference between the ERA-I significant wave height (SWH) and the buoy SWH varies from ?1 to 1 m with an average value of ?0.1 m for the three west coast locations. For the three east coast locations, the variation ranges from ?2.2 to 1.7 m with an average value of ?0.2 m. The ERA-I SWH data show positive biases, indicating an overall overestimation for all locations except for the northern location in the west coast of India, where underestimation is observed. During the tropical cyclone period, a large (~33%) underestimation of SWH in the ERA-I data is observed. Hence, the ERA-I SWH data cannot be used for design applications without site-specific validation. The difference between the wave period from ERA-I and the energy wave period from the buoy varies from ?6 to 4 s with an average value of ?0.3 s. The intercomparisons suggest that the ERA-I dataset shows encouraging agreement with the annual mean SWH and the energy wave period.