Understanding the wave properties in centimeter to decameter (cmDm) wavelength range is of great interest to ocean remote sensing and air-sea interaction. For more than six decades, cmDm waves are generally considered to be in the equilibrium range, and its spectral function has a constant slope: − 5 or − 4 in the 1D frequency spectrum and − 3 or − 2.5 in the 1D wavenumber spectrum. Some variations of the equilibrium spectrum model include varying the frequency spectral slope from − 4 to − 5 at some multiple of the spectral peak frequency, or incorporating a threshold velocity in the reference wind speed. Extensive efforts are then devoted to quantifying the spectral coefficient of the equilibrium spectrum function. This paper emphasizes that the observed wave spectral slope in the ocean is mostly non-constant. Therefore, the wave properties in field observations are significantly different from those inferred from assuming a constant spectral slope. The variable spectral slope is indicative of a non-equilibrium nature of ocean surface waves. Furthermore, from signal-to-noise consideration, surface slope is much more suited than elevation for evaluating the spectral slope and for quantifying the cmDm wave properties. Microwave sensors are excellent instruments for providing the ocean surface slope measurements. Several large datasets of lowpass-filtered mean square slope (LPMSS) have been reported recently. Combining the LPMSS observations with a spectrum function that accommodates a variable spectral slope, several quantitative results on the variable spectral slope and cmDm wave properties are presented.

中文翻译：

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厘米到十米波长的表面波光谱特性：可变光谱斜率和非平衡光谱

了解厘米到十毫米（cmDm）波长范围内的波属性对于海洋遥感和海-海相互作用非常重要。六十多年来，cmDm波通常被认为处于平衡范围内，其频谱函数具有恒定的斜率：在一维频谱中为-5或-4，在一维波数频谱中为-3或-2.5。平衡频谱模型的某些变化包括在频谱峰值频率的某些倍数处将频谱斜率从-4更改为-5，或将阈值速度合并到参考风速中。然后，大量的努力致力于量化平衡光谱函数的光谱系数。本文强调指出，海洋中观测到的波谱斜率大部分是非恒定的。因此，野外观测中的波特性与假定频谱斜率恒定时得出的波特性明显不同。可变的频谱斜率表示海洋表面波的非平衡性质。此外，从信噪比的角度来看，表面坡度比海拔高度更适合评估光谱坡度和量化cmDm波特性。微波传感器是提供海洋表面坡度测量的出色仪器。最近已经报道了几个大的低通滤波均方斜率（LPMSS）数据集。将LPMSS观测值与适应可变频谱斜率的频谱函数相结合，给出了有关可变频谱斜率和cmDm波特性的若干定量结果。