Accession Number : ADA333444

Title :   Estimation of Directional Surface Wave Spectra from a Towed Research Catamaran

Corporate Author : RHODE ISLAND UNIV NARRAGANSETT GRADUATE SCHOOL OF OCEANOGRAPHY

Personal Author(s) : Hanson, Kurt A. ; Hara, Tetsu ; Bock, Erik J. ; Karachintsev, Andrey B.

PDF Url : ADA333444

Report Date : 11 MAR 1997

Pagination or Media Count : 53

Abstract : During the High Resolution Remote Sensing Main Experiment, wave height was estimated from a moving catamaran using pitch rate and roll rate sensors, a three axis accelerometer, and a capacitive wave wire. The wave spectrum in the frequency band ranging roughly from 0.08 Hz to 0.3 Hz was verified by independent buoy measurements. To estimate the directional frequency spectrum from a wave-wire array the Data Adaptive Spectral Estimator is extended to include the Doppler shifting effects of a moving platform. The method is applied to data obtained from a fixed platform during the Ris0 Air Sea Experiment, and data obtained from a moving platform during the Coastal Ocean Processes Experiment. Both results show that the propagation direction of the peak wind waves compares well with the measured wind direction. When swells and local wind waves are not aligned, the method can resolve the difference of propagation directions. Using the fixed platform data a numerical test is conducted which shows that the method is able to distinguish two wave systems propagating at the same frequency but in two different directions.

Descriptors :   *OCEAN WAVES, *SHIP MOTION, *CATAMARANS, ROLL, COASTAL REGIONS, PITCH(MOTION), ACCELEROMETERS, OCEANOGRAPHIC DATA, WIND DIRECTION, WIND VELOCITY, HOT WIRE ANEMOMETERS, DOPPLER EFFECT, BUOYS, RESEARCH SHIPS.

Subject Categories : Physical and Dynamic Oceanography
      Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE