Wednesday, January 14, 2004
"Observations of Steep Wave Statistics in Open Ocean Waters"
Dr. Nicholas Scott Post Doctoral Scholar Applied Ocean Physics and Engineering Woods Hole Oceanographic InstitutionWhere:
GLERL Main Conference Room
2205 Commonwealth Blvd.
Ann Arbor, MI 48105
A new wavelet analysis methodology is proposed to estimate the statistics of steep waves. The method is applied to open ocean wave height data from the Southern Ocean Waves Experiment (1992) and from a field experiment conducted at Duck, North Carolina (1997). Results show that high wave slope crests appear over a wide range of wave numbers, with a large amount being much shorter than the dominant wave. At low wave slope thresholds, all wave fields have roughly the same amount of wave crests regardless of wind forcing. The steep wave statistic decays exponentially with the square of the wave slope threshold, with a decay rate that is larger for the low wind cases than the high wind cases. Comparison of the steep wave statistic with independent measurements of the breaking wave statistic suggests a breaking wave slope threshold of about 0.12. Although the steep wave statistic roughly increases with the cube of the wind speed as the breaking wave statistic does, other factors besides the wind speed also affect the level of the steep wave statistic. Comparison of the steep wave statistic to the saturation spectrum reveals a reasonable correlation at high wave slope thresholds.
For more information, contact:
Dr. Paul Liu
-- David F. Reid, Ph.D. U.S. Department of Commerce National Oceanic and Atmospheric Administration Great Lakes Environmental Research Laboratory 2205 Commonwealth Blvd. Ann Arbor, MI 48105-2945 Voice: 734-741-2019 FAX: 743-741-2055 GLERL home page: http://www.glerl.noaa.gov