Shredding of environmental signals by sediment transport
Shredding of environmental signals by sediment transport
复制标题
DOI：
10.1029/2010gl044638
复制
发表时间：
2010-10-06
影响因子：
5.2
通讯作者：
Paola, Chris
中科院分区：
文献类型：
--
作者：
Jerolmack, Douglas J.;Paola, Chris
地貌对气候、构造运动和海平面做出反应，但这种反应是由沉积物运移调节的。了解环境信号的传递对于预测地貌对气候变化的响应，以及从地层学解释古气候和构造至关重要。在这里，我们提出泥沙输运可以作为一个非线性滤波器，完全摧毁(“碎片”)环境信号。这是由于泥沙输送系统中普遍存在的阈值所致，例如滑坡、推移质输送和河流撕裂。这种“形态动力学湍流”类似于流体流动中的湍流，在流体流动中，以一个频率注入的能量被涂抹在一系列尺度上。我们用一个数值模式表明，当外部信号的时间和幅度尺度落在地形动力湍流范围内时，外部信号被粉碎。随着信号频率的增加，信号保存成为例外，而不是规则，这意味着对所谓的外部强迫的沉积信号进行关键的重新检查。引文：Jerolmack，D.J.和C.Paola(2010)，《泥沙传输对环境信号的粉碎》，地球物理。莱特，37，L19401，DOI：10.1029/2010GL044638。
Landscapes respond to climate, tectonic motions and sea level, but this response is mediated by sediment transport. Understanding transmission of environmental signals is crucial for predicting landscape response to climate change, and interpreting paleo-climate and tectonics from stratigraphy. Here we propose that sediment transport can act as a nonlinear filter that completely destroys ("shreds") environmental signals. This results from ubiquitous thresholds in sediment transport systems; e. g., landsliding, bed load transport, and river avulsion. This "morphodynamic turbulence" is analogous to turbulence in fluid flows, where energy injected at one frequency is smeared across a range of scales. We show with a numerical model that external signals are shredded when their time and amplitude scales fall within the ranges of morphodynamic turbulence. As signal frequency increases, signal preservation becomes the exception rather than the rule, suggesting a critical re-examination of purported sedimentary signals of external forcing. Citation: Jerolmack, D. J., and C. Paola (2010), Shredding of environmental signals by sediment transport, Geophys. Res. Lett., 37, L19401, doi:10.1029/2010GL044638.