Wave field data are affected not only by the accuracy of instruments recording them but also by sampling variability, an uncertainty due to the limited number of observations. For stationary meteorological conditions, due to the randomness of the sea surface elevation, wave parameters derived from a temporal or spatial wave record will depend on which part of a wave record is used in an analysis as well as on the length of a wave record and/or size of the investigated ocean area. This study demonstrates, using numerical simulations, challenges that sampling variability brings in the interpretation of nonlinear wave characteristics of the surface elevation when single 20- or 30-min field wave records are used in an analysis. As examples, we use sea states in which rogue waves were observed in the North Sea and investigate them using linear, second-, and third-order numerical simulations. The third-order wave data are simulated by a numerical solver based on the higher order spectral method (HOSM) which includes the leading order nonlinear dynamical effects, accounting for the effect of modulational instability. Wave steepness, the maximum wave crest, skewness, and kurtosis are investigated in unidirectional and directional wave fields. The study shows that having a single 20- or 30-min wave record may make it difficult to determine on the degree of wave field nonlinearity and the accuracy of derived wave parameters, as well as to evaluate the validity of wave models. Both single-point temporal and stereo-video camera data are discussed. We demonstrate that numerical simulations represent important supporting tools for wave field measurements.

波场数据不仅受到记录仪器的准确性的影响，而且还受到采样变异性的影响，由于观测次数有限，不确定性也受到影响。对于平稳的气象条件，由于海面高程的随机性，从时间或空间波记录导出的波参数将取决于在分析中使用波记录的哪个部分以及波记录的长度和/或所调查海洋区域的大小。这项研究通过数值模拟证明了挑战，当在分析中使用单个20分钟或30分钟的场波记录时，采样变异性会带来对表面高程的非线性波特征的解释。例如，我们使用在北海观察到流浪的海况，并使用线性，二次波，和三阶数值模拟。数值求解器基于高阶频谱方法（HOSM）对三阶波数据进行了仿真，该方法包含了前阶非线性动力学效应，并考虑了调制不稳定性的影响。在单向和定向波场中研究了波的陡度，最大波峰，偏度和峰度。研究表明，只有20分钟或30分钟的波浪记录可能难以确定波场的非线性程度和导出的波浪参数的准确性，也难以评估波浪模型的有效性。讨论了单点时间和立体摄像机数据。我们证明了数值模拟代表了波场测量的重要支持工具。数值求解器基于高阶频谱方法（HOSM）对三阶波数据进行了仿真，该方法包含了前阶非线性动力学效应，并考虑了调制不稳定性的影响。在单向和定向波场中研究了波的陡度，最大波峰，偏度和峰度。研究表明，只有20分钟或30分钟的波浪记录可能难以确定波场的非线性程度和导出的波浪参数的准确性，也难以评估波浪模型的有效性。讨论了单点时间和立体摄像机数据。我们证明了数值模拟代表了波场测量的重要支持工具。数值求解器基于高阶频谱方法（HOSM）对三阶波数据进行了仿真，该方法包含了前阶非线性动力学效应，并考虑了调制不稳定性的影响。在单向和定向波场中研究了波的陡度，最大波峰，偏度和峰度。研究表明，只有20分钟或30分钟的波浪记录可能难以确定波场的非线性程度和导出的波浪参数的准确性，也难以评估波浪模型的有效性。讨论了单点时间和立体摄像机数据。我们证明了数值模拟代表了波场测量的重要支持工具。