Buoy data assimilation to improve wave height assessment in Bay of Bengal during monsoon seasons

Significant wave height assessment in Bay of Bengal derived from third generation Wave Model (WAM cycle 4) has been improved by assimilating with continuous three hourly data from five moored buoys of National Institute of Ocean Technology using optimum interpolation technique. Covariance based weight function (gain) used in the study captures the model physics behind wind-wave process while distributing the errors at any buoy location. Gain composition at different buoy locations, due to assimilation of each buoy has been reported for both southwest (July) and northeast (November) monsoons, for year 2004. Qualitative and quantitative improvement in significant wave height due to buoy data assimilation during these two seasons are presented with reference to changing wind and wave characteristics. The order of improvement is found to be proportional to the magnitude of deviations found with respect to the measurements. Considerable model area has been influenced by assimilation.