Extreme Wave Analysis by Integrating Model and Wave Buoy Data

Abstract

Abstract:Estimating the extreme values of significant wave height (H S ), generally described by the H S return period T R function H S (T R ) and by its confidence intervals, is a necessity in many branches of coastal science and engineering. The availability of indirect wave data generated by global and regional wind and wave model chains have brought radical changes to the estimation procedures of such probability distribution-weather and wave modeling systems are routinely run all over the world, and H S time series for each grid point are produced and published after assimilation (analysis) of the ground truth. However, while the sources of such indirect data are numerous, and generally of good quality, many aspects of their procedures are hidden to the users, who cannot evaluate the reliability and the limits of the H S (T R ) deriving from such data. In order to provide a simple engineering tool to evaluate the probability of extreme sea-states as well as the quality of such estimates, we propose here a procedure based on integrating H S time series generated by model chains with those recorded by wave buoys in the same area.

An Experimental Assessment of Extreme Wave Evaluation by Integrating Model and Wave Buoy Data

“…In order to overcome the problems described in Section 1 to estimate SWH extreme values and return times from model data, a new procedure-in the following indicated as "integrated"-was proposed [4].…”

“…Most of the assimilation procedures are carried out with satellite altimeter data, which are scattered in time (at many hours' intervals) and wide apart in space (tens or hundreds of kilometers), so extreme SWH values may often be missed. It is also worth noting that the sampling time of the models, i.e., the time interval at which data are stored and released, is often higher than the standard sampling time of buoys, thus causing a negative bias on the estimated extreme values [1][2][3].In order to overcome these problems, an integrated procedure [4] was been proposed by some of the authors of the present paper whereby the curves of extreme SWH as a function of the return time T R (in the following: SWH(T R )) deriving from synthetic data are compared and calibrated with the similar curves computed from buoy data in different locations. This provides a way of deriving SWH(T R ) curves for sites where no experimental data are available.The present paper presents an extension of the same technique and provides an experimental authentication of the methodology based on a new large set of reliable data along the coasts of the USA.The determination of the probability of extreme SWH is one of the main problems of coastal, offshore, and marine engineering, so that the relevant literature is not only extensive, but also increasing with time as the technology improves and the requirements become more stringent.…”

“…In order to overcome these problems, an integrated procedure [4] was been proposed by some of the authors of the present paper whereby the curves of extreme SWH as a function of the return time T R (in the following: SWH(T R )) deriving from synthetic data are compared and calibrated with the similar curves computed from buoy data in different locations. This provides a way of deriving SWH(T R ) curves for sites where no experimental data are available.…”

“…The integrated procedure had already been applied for some of the GoM area buoys in [4], but here for the first time a jackknife validation as described in Section 2.2 is carried out. The model data have also been updated to the most recent version (Phase 2) of CFSR dataset, which was not yet available at the time.…”

Using Adjacent Buoy Information to Predict Wave Heights of Typhoons Offshore of Northeastern Taiwan

“…However, performance records of the buoys indicate that there are often no wave data available owing to data loss or other malfunctions. The present study thus hypothesized that if wave heights around a particular buoy could be predicted using data from the adjacent buoy when the target buoy malfunctioned, the problems associated with buoy malfunctioning could be overcome and key information regarding the waves in the target area could still be collected [4]. The aim of this study was to evaluate the feasibility of predicting waves using the data collected by the adjacent buoy.…”