Accession Number:

ADA609715

Title:

Development of a Near-Bed Sediment Flux Sensor

Descriptive Note:

Annual rept.

Corporate Author:

WOODS HOLE OCEANOGRAPHIC INSTITUTION MA

Report Date:

2000-09-30

Pagination or Media Count:

4.0

Abstract:

Our research program focuses on identifying and quantifying sediment erosion, transport, and deposition processes on the continental shelf through state of the art observational techniques in both fine grained and sandy environments. In sandy environments our goal is to understand the detailed interactions and feedbacks between hydrodynamics, bedforms, and the resulting sand transport. In fine grained such as the environments, Eel River shelf we have been investigating the role of gravitationally forced fluid mud flows in the wave boundary layer as a cross-shore transport mechanism. In certain environments bedload or near bottom suspended load can be the dominant mode of sand transport. In particular, these modes of sediment transport can have important impacts in terms of understanding erosion and deposition mechanisms in coarser sand environments with active bedform processes. These bedform processes, which may be forced by bedload transport, have been observed to change the local seafloor elevation tens of centimeters in time scales of hours to days. However, there is a lack of suitable observational techniques to measure bedload and near bottom suspended sand transport and their relationship to the hydrodynamic forcing. Therefore, we are developing and testing acoustic Doppler instrumentation that can quantitatively measure the bedload and near bottom suspended load flux magnitude and direction on a rapid time scale and its relationship to the hydrodynamic forcing. The approach for this project is based on a combination of modeling sensor geometry and response and testing actual systems in laboratory and field environments. The modeling effort will be used to guide development of sensor geometries and signal processing schemes. These will then tested using the components of Coherent Doppler Profiler developed at Dalhousie University.

Subject Categories:

  • Physical and Dynamic Oceanography
  • Acoustic Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE