气候变化领域集成服务门户(CCPortal): A Regime-State Framework for Morphodynamic Modeling of Seabed Roughness

CCPortal

DOI	10.1029/2020JC016769
	A Regime-State Framework for Morphodynamic Modeling of Seabed Roughness
	DuVal C.B.; Trembanis A.C.; Miller D.C.
发表日期	2021
ISSN	21699275
卷号	126 期号:5
英文摘要	Seabed roughness in the dynamic near-shore environment is continuously modified by the interplay of physical and biological processes including bedform morphodynamics and bioturbation. We introduce a novel regime-state framework to determine the dominant modifier of seabed roughness based on observed or estimated physical forcing, which are classified by critical Shields parameter or wave mobility thresholds. The regime-state framework is applied to a set of field observations containing time-lapse sonar imagery of ripple growth, decay, and bioturbation. The rate of ripple decay varies in both physical and biological processes. The decay rate is sensitive to oscillatory forcing magnitude and direction relative to relict ripple orientation and time-evolving ripple height. We found two distinct episodes of ripples decayed by 20%–30% within 4–5 days. Ripple decay models and observations did not agree in rate of decay up to and following the same time period. By varying decay rate using a time-dependent diffusion coefficient determined by the dominant decay mechanism, the regime-state framework resulted in better agreement to field observations. Benthic megafauna are also shown to create seabed roughness, excavating dense fields (>1 pit/m2) of pits (≤84 cm in diameter) that introduce acoustic roughness comparable to 8–12 cm high ripples. The spatiotemporal variability of megafaunal pit formation suggests diffusion-based bioturbation models are not adequate and megafaunal pits require additional parameterization to mechanistically model. The regime-state framework presented in this study serves as a framework for future investigations and modeling of ripple morphodynamics, bioturbation, and roughness. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	Bioturbation; morphodynamics; ripples; roughness
语种	英语
来源期刊	Journal of Geophysical Research: Oceans
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/186332
作者单位	National Research Council, Research Associate Program, Ocean Sciences Division, U.S. Naval Research Laboratory, Stennis Space CenterMS, United States; School of Marine Science and Policy, College of Earth, Ocean, and Environment, University of Delaware, Newark, DE, United States
推荐引用方式 GB/T 7714	DuVal C.B.,Trembanis A.C.,Miller D.C.. A Regime-State Framework for Morphodynamic Modeling of Seabed Roughness[J],2021,126(5).
APA	DuVal C.B.,Trembanis A.C.,&Miller D.C..(2021).A Regime-State Framework for Morphodynamic Modeling of Seabed Roughness.Journal of Geophysical Research: Oceans,126(5).
MLA	DuVal C.B.,et al."A Regime-State Framework for Morphodynamic Modeling of Seabed Roughness".Journal of Geophysical Research: Oceans 126.5(2021).