Improving the WAVEWATCH-III wave model results using data assimilation in the Persian Gulf

Abstract

In this study, data assimilation with bulk and partitioned spectral parameters were integrated into the WAVEWATCH-III (WW3) wave model. The dependency of future forecasts on the current state in numerical models leads to an error flow in the results. Data assimilation schemes, such as the optimum interpolation, compensate for the problem by using available observations to minimize the error in the current state of the model. Different wind input and wave dissipation packages of WW3 were assessed for the Persian Gulf. The data assimilation scheme was integrated with the most successful formulation, ST3BJA. The enhanced WW3 model was assessed for two time periods in the Persian Gulf in which the wave data from three in-situ ADCPs were available. In addition, the satellite-derived wave height data within the computational domain were also used for model assessment. Assimilating the significant wave height data from in-situ measurements improved the model results in all cases and reduced the underestimation of significant wave height and improved the wave period statistics, significantly. The inclusion of mean wave period or use of partitioning the spectrum in the assimilation process resulted in spurious oscillations in the time series of peak wave period and significant wave height. Since the swells are not energetic in the Persian Gulf, the results from assimilation with partitioning spectrum scheme is not as successful as from assimilation scheme with the bulk parameters in reproducing accurate total wave height.