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Across‐shelf sediment transport: Interactions between suspended sediment and bed sediment

 

作者: Courtney K. Harris,   Patricia Wiberg,  

 

期刊: Journal of Geophysical Research: Oceans  (WILEY Available online 2002)
卷期: Volume 107, issue C1  

页码: 81-812

 

ISSN:0148-0227

 

年代: 2002

 

DOI:10.1029/2000JC000634

 

数据来源: WILEY

 

摘要:

We use a two‐dimensional, time‐dependent sediment‐transport model to quantify across‐shelf transport, deposition, and sorting during wave‐driven resuspension events characteristic of those that dominate sediment transport on many continental shelves. Decreases in wave‐orbital velocities as water depth increases, and the resulting cross‐shelf gradient in bed shear stress favor a net offshore transport of sediment. On wide, flat shelves (slopes ∼0.1%percnt;), these gradients are low, and the depth to which the seabed is reworked depends mainly on bottom shear stress and local sediment availability. On narrow, steep shelves (slopes ∼0.5%percnt;), however, the gradient in bottom stress generates significant cross‐shelf suspended sediment flux gradients that create regions of net erosion and deposition. While the magnitude of waves generally determines the water depth to which sediment can be resuspended, erosional and depositional patterns on narrow shelves are sensitive to cross‐shelf gradients in wave energy, nonlocal sediment availability, and the direction and magnitude of the cross‐shelf current. During energetic waves, cross‐shelf divergence of suspended sediment flux can create a coarsened, erosional area on the inner shelf that abuts a region of fine‐grained sediment deposition on the mid‐to‐outer shelf. If currents are strongly shoreward, however, flux divergence leads t

 

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