Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 48 for “"acoustic Doppler current profiler"”.
-
Use of numerical simulations to investigate the performance of a virtual acoustic Doppler current profiler in characterizing flow
… and temporal sampling strategies of a virtual acoustic Doppler current profiler (ADCP) in characterizing flow fields and mean velocity profiles from stationary and moving platforms. This was accomplished in part using a data set with high temporal and spatial resolution from a direct numerical …
-
Characteristics of near surface circulation patterns in the Benguela as derived from the ADCP(Acoustic Doppler Current Profiler).
… evaluate their respective accuracy in depicting current flow. The raw data were validated (edited and calibrated) using the CODAS software package before the current vectors could be drawn. TRANSECT -processed data could not be validated therefore vectors were drawn from the un-validated data. …
-
Measuring surface ocean wave height and directional spectra using an Acoustic Doppler Current Profiler from an autonomous underwater vehicle
The Acoustic Doppler Current Profiler (ADCP) is a proven technology which is capable of measuring surface wave height and directional information, however it is generally limited to rigid, bottom mounted applications which limit its capabilities for measuring deep water waves. By employing an …
-
Measuring surface ocean wave height and directional spectra using an Acoustic Doppler Current Profiler from an autonomous underwater vehicle
The Acoustic Doppler Current Profiler (ADCP) is a proven technology which is capable of measuring surface wave height and directional information, however it is generally limited to rigid, bottom mounted applications which limit its capabilities for measuring deep water waves. By employing an …
-
Vertical Distributions of Zooplankton at the Mouth of Chesapeake Bay and Calibration of Backscatter From an Acoustic Doppler Current Profiler
… Bay and attempted to derive biological data from acoustic Doppler current profiler (ADCP) backscatter. A single site was occupied in the North Channel at the mouth of Chesapeake Bay (37° 04' N, 75° 58' W) from 17.0–19.7 November 1999. Temperature, salinity, fluorescence, light transmission, …
-
Currents through the Golden Gate
… a bottom mooring consisting of an upward looking acoustic doppler current profiler (ADCP) and a conductivity-temperature pressure (CTD) instrument were deployed in the Golden Gate. Tidal constituents were derived from least squares fit on pressure and current data. The amplitude of the M2 tide was …
-
The Variability of High-Frequency Motions and Their Interactions with the Mesoscale on the Mississippi Shelf
… mesoscale motions. For this purpose, we use Acoustic Doppler Current Profiler (ADCP) measurements collected at nearshore (23 m), mid-shelf (60 m), and shelf break (88 m) stations. High-frequency motions are defined as motions with periods less than 36 hours, whereas mesoscale motions have …
-
Current velocity profiling from an autonomous underwater vehicle with the application of Kalman filtering
… schemes for extracting Earth-referenced current velocity from relative current velocity measurement made by an Acoustic Doppler Current Profiler (ADCP) borne by an Autonomous Underwater Vehicle (AUV). Compared with conventional approaches, current profiling from an AUV platform has …
-
Wind, sea ice, inertial oscillations and upper ocean mixing in Marguerite Bay, Western Antarctic Peninsula : observations and modeling
… draft and velocity from moored upward-looking acoustic Doppler current profiler data. A linear momentum balance shows the importance of internal ice stresses in the observed motion of the ice pack. Strong inertial, not tidal, motions were observed in both the sea ice and upper ocean. Estimates …
-
Wind, sea ice, inertial oscillations and upper ocean mixing in Marguerite Bay, Western Antarctic Peninsula : observations and modeling
… draft and velocity from moored upward-looking acoustic Doppler current profiler data. A linear momentum balance shows the importance of internal ice stresses in the observed motion of the ice pack. Strong inertial, not tidal, motions were observed in both the sea ice and upper ocean. Estimates …
-
Navigation and target localization performance of the autonomous underwater vehicle REMUS
… may come from a number of sources such as an Acoustic Doppler Current Profiler, Long Baseline acoustic travel times to known beacons, Inertial Measuring Units, or Sonar. The objective of this research was to develop a Kalman filter-based navigation algorithm for the AUV REMUS that improves …
-
Design and Simulation of a Towed Underwater Vehicle
Oceanographers are currently investigating small-scale ocean turbulence to understand how to better model the ocean. To measure ocean turbulence, one must measure fluid velocity with great precision. The three components of velocity can be used to compute the turbulent kinetic energy dissipation …
-
Improvements to a Real-Time, Satellite-Derived Surface Current Product (OSCAR) and Evaluation in the Intra-American Sea
… predictive coding for use in the Ocean Surface Currents Analysis, Real-time (OSCAR) is developed and tested. This method is implemented by Earth and Space Research (ESR) to produce operational height fields that are in turn used to calculate the geostrophic component velocity of OSCAR. The …
-
Mixing and secondary circulation in Juan de Fuca Strait
… the dynamics associated with mixing and currents within these bodies of water. Pollutants and fresh water from river runoff flow out to sea in the upper layer, while nutrient-carrying oceanic water returns beneath. While there have been many studies of the processes involved in this …
-
A qualitative and physical analysis of processes around the Mascarene plateau
… the October/November 2008 ASCLME (Agulhas Somali Current Large Marine Ecosystem) cruise on board the Dr Fridtjof Nansen which surveyed the region around the Mascarene Plateau. Due to the paucity of data in the region, the cruise was a routine cruise with no specific scientific questions to be …
-
Error and uncertainty in estimates of Reynolds stress using ADCP in an energetic ocean state
… as the turbulent flow is advected with the mean current (Taylor's frozen turbulence approximation). However, the Acoustic Doppler Current Profiler (ADCP) looks at radial wavenumbers and frequencies, and finds overlap. Another approach is to exploit the physical differences of each process, namely …
-
Sea ice thickness and iceberg distribution in the Southern Ocean
… is limited. A novel methodology, using an acoustic Doppler current profiler, was developed to measure sea ice draft based on measurements taken from Autosub (an autonomous underwater vehicle). The PDF has been derived for three missions undertaken in the eastern Amundsen Sea during March …
-
Towfish Design, Simulation and Control
… The turbulence can be near the noise level of current microscale profiling techniques and these techniques do not provide spatially and temporally dense measurements and can be labor intensive. A 5 beam acoustic Doppler current profiler (VADCP) can more accurately measure three components of …
-
A method for on-line water current velocity estimation using low-cost autonomous underwater vehicles
… Additionally, some capabilities such as water current velocity measurement traditionally requires the addition of equipment that is not only expensive, but also whose size and power consumption can adversely affect operating characteristics and deployment times. This thesis expands on previous …
-
A method for on-line water current velocity estimation using Lol-cost autonomous underwater vehicles
… Additionally, some capabilities such as water current velocity measurement traditionally requires the addition of equipment that is not only expensive, but also whose size and power consumption can adversely affect operating characteristics and deployment times. This thesis expands on previous …
Page 1 of 3