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Wave height analysis from 10 years of observations in the Norwegian Sea.
- Source :
-
Continental Shelf Research . Jan2014, Vol. 72, p47-56. 10p. - Publication Year :
- 2014
-
Abstract
- Abstract: Large waves pose risks to ships, offshore structures, coastal infrastructure and ecosystems. This paper analyses 10 years of in-situ measurements of significant wave height (H s ) and maximum wave height (H max ) from the ocean weather ship Polarfront in the Norwegian Sea. During the period 2000 to 2009, surface elevation was recorded every 0.59s during sampling periods of 30min. The H max observations scale linearly with H s on average. A widely-used empirical Weibull distribution is found to estimate average values of H max /H s and H max better than a Rayleigh distribution, but tends to underestimate both for all but the smallest waves. In this paper we propose a modified Rayleigh distribution which compensates for the heterogeneity of the observed dataset: the distribution is fitted to the whole dataset and improves the estimate of the largest waves. Over the 10-year period, the Weibull distribution approximates the observed H s and H max well, and an exponential function can be used to predict the probability distribution function of the ratio H max /H s . However, the Weibull distribution tends to underestimate the occurrence of extremely large values of H s and H max . The persistence of H s and H max in winter is also examined. Wave fields with H s >12m and H max >16m do not last longer than 3h. Low-to-moderate wave heights that persist for more than 12h dominate the relationship of the wave field with the winter NAO index over 2000–2009. In contrast, the inter-annual variability of wave fields with H s >5.5m or H max >8.5m and wave fields persisting over ~2.5 days is not associated with the winter NAO index. [Copyright &y& Elsevier]
- Subjects :
- *WATER waves
*OCEANOGRAPHY
*ECOSYSTEMS
*EMPIRICAL research
*RAYLEIGH model
Subjects
Details
- Language :
- English
- ISSN :
- 02784343
- Volume :
- 72
- Database :
- Academic Search Index
- Journal :
- Continental Shelf Research
- Publication Type :
- Academic Journal
- Accession number :
- 93270559
- Full Text :
- https://doi.org/10.1016/j.csr.2013.10.013