Buoy Data Assimilation in Nearshore Wave Modelling (Assimilatie van boeigegevens in de modellering van golven nabij de kust)

Abstract:

The study of wind waves deserves major attention at present time as they play a very important role in many human activities. Thanks to numerical modelling, at present wave estimates are available at global scale and with an outstan ding degree of accuracy. Previously, measurements have served mainly to verify and calibrate models, but more recently the abundance of in-situ and remote sensed data have motivated the incorporation of measurements into the models in a process known as data assimilation. The focus of this study is the assimilation of offshore buoy data in the nearshore wave modelling scenario, looking for improvements of wave hindcasts at coasta l locations. The model used is WAM, a state-of-the-art third generation wa ve model. The assimilation approach is the so called Optimal Interpolation (OI). This method has some advantages over other methods as it is rather straightforward to implement and it is computationally very efficient. H owever, two major limitations are inherent in this method. The first is the a-pr iori representation of the errors characteristics of the system, and the seco nd the retrieval of analyzed magnitudes into the wave spectrum. The confrontati on of these shortcomings has largely drawn the experimental line followed in t his study. For the former, it is recognized that the successful implementation of a ny assimilation system requires a proper knowledge of the spatial structure of the syste ms errors (model and observations). However, that knowledge is in general v ery poor and that is the case for the present study area. Therefore, differe nt parameterizations of the gain matrix were tested. The OI scheme …

Año de publicación:

2009

Keywords:

Fuente:

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