Earther.Gizmodo.com的文章[科学家发现一种奇怪的噪音来自南极冰架][1]美国地球物理联盟链接视频(一种更重要的是*音频*)(AGU)南极冰架(这是一个听起来像][2]。也链接到最近出版的《地球物理研究信(Chaput et al . 2018年)[列车表面附近环境迫使罗斯冰架的变化观察到与周围地震噪声)[3](开放),下面的图片。量纲分析仅表明长度范围内的现象导致这些稍微sub-sonic振荡可以获得速度除以频率(如m / s除以1 / s)但使用声速在冰或水(分别约4000和1500 m / s)和大约10 Hz表明几百米的长度尺度。论文本身相当技术和深度。在那里,有物理距离在水里,或在冰对应于这个频率,或者由于振荡频率动态过程如粘和下滑,而不是声音的传播速度?[!(图3中,Chaput et al . 2018][4]][4]标题图3:> (a)边际产后抑郁症Vp和Vs premelt站DR09共振,得到的功率谱密度反演(参见附加的。S4: 1 D密度反演,应承担卡佩里et al ., 2016)。红色曲线表明边际后对P和S意味着速度。(b)上面板,代表功率谱模型的子集(红色曲线)的产后抑郁症(一)站DR09,相比之下,观察到premelt光谱(蓝色曲线)。 Bottom panel, averaged observed premelt and postmelt spectral resonances (blue and green curves, respectively) at DR09. (1) and (2) indicate the position of a higher frequency peak of interest before and after the melt event. (c) Contour plot depicting a grid search of penetration depth versus velocity perturbation applied to the premelt model (peak pattern (1), in b), and fit to the postmelt resonance peak pattern, as denoted by peak pattern (2) in (b), lower panel. The minimum with respect to a least squares fit is represented by the red star, denoting a 35–40% perturbation with a depth penetration of 3–4 m. The premelt model used here is the mean posterior model shown in (a). (d) Example frequency peak response to a 40% velocity drop with varying degrees of depth penetration for the DR09 premelt velocity model in (a). Note that lower frequency spectral peaks can be nearly unaffected if the perturbation depth is shallow. (1) and (2) denote observed premelt and postmelt peaks plotted in (b). PPD = Posterior Probability Distributions; MCMC = Markov chain Monte Carlo. [1]: https://earther.gizmodo.com/scientists-discover-a-weird-noise-coming-from-antarctic-1829793363 [2]: https://www.youtube.com/watch?v=w56RxaX9THY [3]: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL079665 [4]: https://i.stack.imgur.com/ash7C.jpg