Multi-peaked directional wave spectra have been estimated by the well-known maximum likelihood method and modeled by applying a numerical optimization approach that uses a gradient OQNLP algorithm. The research is based on field measurement data from a 210-km-long area at the northern coasts of the Gulf of Oman. This modeling approach allows the fitting of various spectral models. Accordingly, three directional spectrum models with combinations of frequency and directional spreading functions have been evaluated and proper models for directional waves have been presented. On the other hand, the introduced optimization algorithm is modified by adding a constraint to zeroth-order spectral moment (m₀) value to improve the fitting accuracy in the frequency spectrum. It has been shown that selecting the appropriate model for each of the frequency and directional functions can significantly improve the performance of both. Among the evaluated directional models, the accuracy of the results based on both JONSWAP Sech² and Gamma Sech² models was about 25% better in the frequency domain and about 10% better in the full directional domain than JONSWAP Cos^2s model. Besides, in most of the observed swell components, because of their wide spectrums with low peak values, the use of the Gamma frequency model performs better than the JONSWAP model.

多峰定向波谱已通过众所周知的最大似然法进行了估算，并通过应用使用梯度OQNLP算法的数值优化方法进行了建模。该研究基于阿曼湾北部海岸210公里长区域的现场测量数据。这种建模方法可以拟合各种光谱模型。因此，已经评估了具有频率和定向扩展功能的组合的三个定向频谱模型，并且已经提出了用于定向波的适当模型。另一方面，通过对零阶谱矩（m ₀）值，以提高频谱拟合的准确性。已经表明，为每个频率和方向函数选择合适的模型可以显着改善两者的性能。在评估的方向模型中，基于JONSWAP Sech ²和Gamma Sech ²模型的结果的准确性在频域上比JONSWAP Cos ^2s模型高25％，在全方向域上高10％。此外，在大多数观察到的膨胀分量中，由于它们的频谱范围广且峰值较低，因此使用Gamma频率模型的性能要优于JONSWAP模型。