Attenuation and Directional Spreading of Ocean Waves During a Storm Event in the Autumn Beaufort Sea Marginal Ice Zone
Attenuation and Directional Spreading of Ocean Waves During a Storm Event in the Autumn Beaufort Sea Marginal Ice Zone
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秋季波弗特海边缘冰区风暴事件期间海浪的衰减和定向传播
DOI：
10.1029/2018jc013763
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
P. Wadhams
中科院分区：
文献类型：
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作者：
F. Montiel;V. Squire;M. Doble;J. Thomson;P. Wadhams
本文研究了大振幅波在薄煎饼冰中的衰减和定向传播。根据2015年10月在波弗特海3天风暴事件中收集的原位波浪浮标数据，分析了方向谱密度。从能量密度谱中获得的波浪振幅的两个代理度量，即谱幅和有效波高，用于跟踪波浪沿着横断面通过主要为煎饼状冰原的浮标阵列传播的过程。两种类型的波浪浮标在分析和比较中显示出波浪能量密度和方向性估计的显着差异。虽然主要观测到指数衰减，但两种浮标类型中的一种表明波能密度与线性波衰减的发生之间存在潜在的正相关关系，而不是指数衰减，这与最近在南极边缘冰带的观测结果一致。讨论了影响这一观察结果有效性的因素。指数衰减系数与波频之间也存在一个指数为2.2的经验幂律。波谱的方向性内容似乎沿着波的横断面持续下降，证实波的能量是被煎饼冰耗散，而不是被冰饼分散。
This paper investigates the attenuation and directional spreading of large amplitude waves traveling through pancake ice. Directional spectral density is analyzed from in situ wave buoy data collected during a 3‐day storm event in October 2015 in the Beaufort Sea. Two proxy metrics for wave amplitude obtained from energy density spectra, namely, spectral amplitude and significant wave height, are used to track the waves as they propagate along transects through the array of buoys in the predominantly pancake ice field. Two types of wave buoys are used in the analysis and compared, exhibiting significant differences in the wave energy density and directionality estimates. Although exponential decay is observed predominantly, one of the two buoy types indicates a potential positive correlation between wave energy density and the occurrence of linear wave decay, as opposed to exponential decay, in accord with recent observations in the Antarctic marginal ice zone. Factors affecting the validity of this observation are discussed. An empirical power law with exponent 2.2 is also found to hold between the exponential attenuation coefficient and wave frequency. The directional content of the wave spectrum appears to decrease consistently along the wave transects, confirming that wave energy is being dissipated by the pancake ice as opposed to being scattered by ice cakes.