Recently (Adcock and Taylor, 2009) devised a method to estimate the underlying directional spreading from a single point measurement. Subsequently, this method has been successfully applied to sea states with frequency independent directional spreading. In contrast, the present work has applied this method to synthetic sea states generated with an underlying frequency dependent spreading. However, in the application of the method, it was assumed that the underlying sea states have a frequency independent spreading. It was found that applying this method in this manner predicts directional spreading that is close to the spectrally averaged spreading. Re–computing the widely used Velocity Reduction Factor (vrf) based on the predictions from the new method showed that it agreed within $\pm 1.5\text{\%}$ with the actual value, showing that a reasonable estimate of the directional spreading can be obtained by the new method even under the restrictive assumption of frequency independent spreading. The major implication of these findings is that, a reasonable estimate of the directional spreading function can be obtained for sea states with complex spreading from a single point measurement even with the assumption of frequency dependent spreading.

最近（Adcock和Taylor，2009年）设计了一种方法，可以根据单点测量来估算潜在的方向性扩展。随后，该方法已成功应用于具有频率独立方向性扩展的海况。相反，当前的工作已经将该方法应用于以潜在的频率相关的扩展所产生的合成海洋状态。但是，在该方法的应用中，假设基础海况具有与频率无关的扩展。发现以这种方式应用该方法可预测接近频谱平均扩展的方向扩展。重新计算广泛使用的速度降低因子（vrf）基于新方法的预测表明， $\pm 1.5\text{％}$实际值表明，即使在频率独立扩频的限制性假设下，通过新方法也可以获得合理的定向扩频估计。这些发现的主要含义是，即使假设频率依赖扩展，也可以从单点测量获得具有复杂扩展的海状态的定向扩展函数的合理估计。