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Sediment Transport at LEO-15

The NOAA Middle Atlantic Bight National Undersea Research Center has established several Long term Ecosystem Obsevatory (LEO) sites to study coastal ocean processes such as sediment transport. One of these sites ( LEO-15 ) is located off the coast of southern New Jersey in approximately 15m deep water. The goal of the WHOI sediment transport program at LEO-15 is to make detailed observations of sediment transport processes and to analyze these observations in order to better understand the complex relations between the sediment tranport processes and the relevant physical forcing mechanisms. To meet this goal in 1993 WHOI scientists Jim Lynch , Jim Irish , and graduate student Peter Traykovski began a series of bottom moored tripod deployments at the LEO-15 site. At this time two major sets of deployments have taken place in the late spring/early summer of 1994, and the late summer/early fall of 1995. In this document we will describe some of the instrumentation systems that were deployed and display some of the results from these deployments.
Bathymetry and site description of LEO-15

  1999 Deployment 
DATA FROM LEO-15 WHOI-DALHOUSIE Sediment Transport Sensor Frame
Rotary Sidescan Sonar  Image   of the Seafloor
    Shows the planform of ripple morphology. Bright colors are surfaces facing towards the sonar.
Vertical Pencil Beam Sonar Image
     A vertical slice of sonar imagery showing the bedform profile along a line and puffs of suspended sediment.
1999 Deployment page....under development

1995 Deployment 
In this deployment the same acoustic backscattering systems that were deployed in 1994 were used, but we also deployed a Rotary SideScan Sonar (SSS) to make images of the bottom bedforms. Six tropical storm passed to the east of the site in this deployment providing a very interesting data set.
Instruments deployed on the 1995 LEO-15 Tripod.
Overview of the 1995 deployment Acoustic Backscattering time series with wave and current forcing. 
The Sector Scanning Sonar data is best viewed as a movie so you can see the evolution of the ripple patterns in response to wave forcing. Before you look at the movies take a look at one frame to famaliarize yourself with the movie data presentation format. 
  • Movie 1 (8.4Mb-mpeg ) shows ripples changing direction in response to swell direction via a interesting "ripple kinking" mechanism
  • Movie 2 (11.4Mb-mpeg ) shows the formation and onshore migration of the largest ripples seen during the deployment.
  • Movie 3 (6.3Mb-mpeg) shows the erosion of these large ripples by first shorter waves, and then a large current event.

1994 Deployment
This deployment featured acoustic and optical backscattering measurements of suspended sediment and water velocity measurements.
  • Overviews of the May and June segements of the deployment
  • Plumes of sediment suspended and advected by waves
  • Image and Movie of biological scatterers gathering near a front
  • Acoustic scattering from bubbles injected by surface waves
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    Created and Mantained by Peter Traykovski (last update: 2/28/96)