Field observations of linear transition ripples during an autumn storm exhibit high correlation b... more Field observations of linear transition ripples during an autumn storm exhibit high correlation between cross-shore ripple migration rate and the skewness of the near-bed wave orbital velocity. For a bimodal spectrum of mixed sea and swell, negatively skewed near-bed orbital velocities were accompanied by offshore ripple migration, while for unimodal swell, ripples migrated onshore under positively skewed velocities. Bispectral analysis
Field observations were made in 3-4 m water depth of linear transition ripple geometry and migrat... more Field observations were made in 3-4 m water depth of linear transition ripple geometry and migration using a high-resolution laser-video bed profiling system and acoustic scanning sensors during both the growth and decay phases of an autumn storm event. Linear transition ripples are long-crested, low-steepness bedforms of the anorbital ripple type and were observed to occur here at relatively high
The Journal of the Acoustical Society of America, 2005
Results are presented from the acoustic remote sensing component of Dalhousie University's i... more Results are presented from the acoustic remote sensing component of Dalhousie University's interdisciplinary Coastal Ocean Observatory in Lunenburg Bay, Nova Scotia, operational since June 2002 (www.cmep.ca/bay). Remote acoustic measurements of water column velocity and backscatter are made from bottom-mounted instruments hard-wired to surface buoys. The data are telemetered in near real-time to a shore station via wireless Ethernet, and to Dalhousie over the Internet. The fixed-point measurements from the bottom pods are augmented by a vessel-mounted profiling system, and by opportunistic deployments of internally-recording instruments. Highlights from the first three years of the observing system operation will be presented, including sediment suspension from the seabed and bubble penetration from the surface during Hurricane Juan.
Journal of Atmospheric and Oceanic Technology, 1999
A pulse-to-pulse coherent acoustic Doppler profiler has been developed for high-resolution partic... more A pulse-to-pulse coherent acoustic Doppler profiler has been developed for high-resolution particle velocimetry in the ocean, in particular for remote measurements of suspended sediment flux and turbulence in the nearshore and continental shelf bottom boundary layer. Acoustic backscatter estimates of suspended particle concentration and velocity are determined simultaneously from the phase and amplitude of the backscattered signal over an O(1
Field observations of linear transition ripples during an autumn storm exhibit high correlation b... more Field observations of linear transition ripples during an autumn storm exhibit high correlation between cross-shore ripple migration rate and the skewness of the near-bed wave orbital velocity. For a bimodal spectrum of mixed sea and swell, negatively skewed near-bed orbital velocities were accompanied by offshore ripple migration, while for unimodal swell, ripples migrated onshore under positively skewed velocities. Bispectral analysis
Field observations were made in 3-4 m water depth of linear transition ripple geometry and migrat... more Field observations were made in 3-4 m water depth of linear transition ripple geometry and migration using a high-resolution laser-video bed profiling system and acoustic scanning sensors during both the growth and decay phases of an autumn storm event. Linear transition ripples are long-crested, low-steepness bedforms of the anorbital ripple type and were observed to occur here at relatively high
The Journal of the Acoustical Society of America, 2005
Results are presented from the acoustic remote sensing component of Dalhousie University's i... more Results are presented from the acoustic remote sensing component of Dalhousie University's interdisciplinary Coastal Ocean Observatory in Lunenburg Bay, Nova Scotia, operational since June 2002 (www.cmep.ca/bay). Remote acoustic measurements of water column velocity and backscatter are made from bottom-mounted instruments hard-wired to surface buoys. The data are telemetered in near real-time to a shore station via wireless Ethernet, and to Dalhousie over the Internet. The fixed-point measurements from the bottom pods are augmented by a vessel-mounted profiling system, and by opportunistic deployments of internally-recording instruments. Highlights from the first three years of the observing system operation will be presented, including sediment suspension from the seabed and bubble penetration from the surface during Hurricane Juan.
Journal of Atmospheric and Oceanic Technology, 1999
A pulse-to-pulse coherent acoustic Doppler profiler has been developed for high-resolution partic... more A pulse-to-pulse coherent acoustic Doppler profiler has been developed for high-resolution particle velocimetry in the ocean, in particular for remote measurements of suspended sediment flux and turbulence in the nearshore and continental shelf bottom boundary layer. Acoustic backscatter estimates of suspended particle concentration and velocity are determined simultaneously from the phase and amplitude of the backscattered signal over an O(1
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