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Data from a cross-shore array of acoustic sensors at the US Army Corps of Engineers Field Research Facility is examined for evidence of wave transformation and longshore currents across the surf zone by comparing several events in 2009-10 with different wave statistics. Hurricane Bill (Hs = 3+ m, Tp = 18 s) was a long-period wave event with strong evidence of non-linear wave transformations, and a...
Utilizing a commercially available acoustic Doppler velocimeter, the Nortek Vectrino with optional plus (+) firmware, measurements of turbulence are made in a turbulent open channel flow in the 8m Research Flume of the DeFrees Hydraulics Laboratory. The measurements are used to estimate dissipation (ε) from Kolmogorov's 2/3, 5/3 and 4/5 Laws as well as integration of the dissipation spectrum. Corrections...
In the Western Scheldt estuary a 45-day campaign took place to measure ship induced waves and currents on a tidal flat. It was established that the hydraulic loads due to the passing ships were large enough to play a major part in the erosion process of the tidal flat.
Personal knowledge of the author stretches from the Geodyne 850 current meter, predecessor of the VACM in 1969 to his own development of MAVS and its recent innovations. Housings, recording media, velocity sensors, and compasses have changed most noticeably. Applications of current measurements are next most striking about the developments in our field over the last 40 years. Where and how current...
Phased array surface current and wave radar systems use electronic beam steering technology to receive radio wave backscatter from the sea surface in narrow beams. This session will present objective information on phased array surface current and wave radar systems by vendors and users.
The Tenth Working Conference on Current Measurement Technology (CMTC) is actually the first Current, Waves and Turbulence Measurement Workshop (CWTM). This conference is a direct descendent of the CMTC workshops of former years. The theme of this conference is “Advances in Lagrangian and Eulerian Measurement Techniques and Observations of Current, Waves and Turbulence.” Like the previous Conferences,...
There are many times when it is useful to operate or test acoustic profiling and velocity sensors in laboratory facilities. Unfortunately, the often clean, clear water in such facilities provides little or no backscatter for these instruments to operate. Additional scatterers may be introduced in some cases but this can be unpractical in large facilities or may introduce volumes of particulate matter...
Acoustic Doppler measurements of flow benefit from scatterers and from suppression of noise. The introduction of micro bubbles into laboratory flows provide excellent targets but also contribute enough buoyancy to produce a rising plume. Zedel and Butt have adapted the dissolved air floatation method from mining to generate right-sized bubbles. Bubble size can be controlled to some degree by injecting...
In order to measure current profiles, and most recently, turbulent fluxes, moored profiling instrument have been equipped with acoustic travel-time current sensors. Noise in the measured currents has exceeded expectations. A customized Falmouth Scientific acoustic current sensor on a McLane Moored Profiler (MMP) has a standard deviation of measured velocity that is 4.4% of the profiler velocity in...
This paper introduces the over-the-horizon radar technique optimized for oceanographic applications. The relation between radar range and operating frequency will be explained as well as the radar resolution which depends on the radar bandwidth. The accuracy in azimuth strongly depends on the number of used receive antennae and samples demonstrate the high accuracy that can be achieved. The oceanographic...
The majority of High Frequency (HF) radars used worldwide operate at medium to high frequencies (8 to 30 MHz) providing spatial resolutions ranging from 3 to 1.5 km and ranges from 150 to 50 km. This paper presents results from the deployment of a single Very High Frequency (VHF, 48 MHz) WEllen RAdar (WERA) radar with spatial resolution of 150 m and range 10-15 km, used in the nearshore off Cape Hatteras,...
Emerging technologies in web-based services have enabled the integration of global, interdisciplinary earth observations. These capabilities can provide an unprecedented opportunity to promote the establishment and adoption of standards for the delivery of information about sensor systems which can enable data quality assessment by disparate users. Machine-to-machine harvesting of data can either...
In this session, three perspectives on the assessment of data quality are presented. One approach is to validate sensor and system performance. Another approach is to define common quality control tests to be administered by data providers of real-time data. A third perspective is to utilize metadata-rich web services to enable dynamic assessment of observational data.
Since its introduction in 1992, the Teledyne RDI Instruments (TRDI) Workhorse ADCP has become ubiquitous, with literally thousands of systems deployed in nearly every body of water on earth. While the measurement itself remains relatively unchanged, in the intervening years the use of the measurements has changed to an extraordinary extent. Originally a novel way to measure currents sorely in need...
More than nine years of ADCP data have been collected in the nearshore at a field station at Spessard Holland North Beach Park, located in Melbourne Beach on the central Atlantic coast of Florida1. The nearly continuous record includes high-resolution directional wave spectra, current profiles, and tide elevations, and the data are being used to 1) study the characteristics of Florida's nearshore...
This paper summarizes the quality control (QC) tests used to verify ocean wave and in situ current data collected and shared by ocean observing systems, federal data centers and oceanographic research institutions. The categories in common for both waves and currents are defined as: (1) sensor health, (2) signal quality, and (3) parameter quality. The main differences being that while wave measurements...
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