Evaluation of ADCP Wave Measurements
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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Nearshore wave information is important to a variety of United States Navy operations in the littorals, including mine warfare, amphibious operations, small boat operations and special forces insertions. The objective of this thesis is to evaluate the accuracy of Teledyne RDI Acoustic Doppler Current Profilers ADCP, in measuring wave height and direction spectra, so that the military can use these for routine wave measurements nearshore. This study uses ADCP data collected in 25 and 45 m depths during the fall 2003 Nearshore Canyon Experiment NCEX off La Jolla, California. Data were first corrected for dropouts. Next the data quality was verified through a consistency check on the redundant velocity measurements of opposing beams, an evaluation of high frequency spectral noise levels, and a comparison of velocity and pressure measurements using linear wave theory. Finally wave height and direction spectra estimated from the ADCP data were compared to data from a directional wave buoy. The analysis revealed that the ADCP data can suffer from low signal to noise ratios in benign conditions and deeper water. Whereas the wave height estimates are sensitive to these errors, the wave direction estimates are surprisingly robust.
- Physical and Dynamic Oceanography
- Undersea and Antisubmarine Warfare
- Radiofrequency Wave Propagation