A multimodal wave spectrum-based approach for statistical downscaling of local wave climate

Journal of Physical Oceanography
By: , and 

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Abstract

Characterization of wave climate by bulk wave parameters is insufficient for many coastal studies, including those focused on assessing coastal hazards and long-term wave climate influences on coastal evolution. This issue is particularly relevant for studies using statistical downscaling of atmospheric fields to local wave conditions, which are often multimodal in large ocean basins (e.g. the Pacific). Swell may be generated in vastly different wave generation regions, yielding complex wave spectra that are inadequately represented by a single set of bulk wave parameters. Furthermore, the relationship between atmospheric systems and local wave conditions is complicated by variations in arrival time of wave groups from different parts of the basin. Here, we address these two challenges by improving upon the spatiotemporal definition of the atmospheric predictor used in statistical downscaling of local wave climate. The improved methodology separates the local wave spectrum into “wave families,” defined by spectral peaks and discrete generation regions, and relates atmospheric conditions in distant regions of the ocean basin to local wave conditions by incorporating travel times computed from effective energy flux across the ocean basin. When applied to locations with multimodal wave spectra, including Southern California and Trujillo, Peru, the new methodology improves the ability of the statistical model to project significant wave height, peak period, and direction for each wave family, retaining more information from the full wave spectrum. This work is the base of statistical downscaling by weather types, which has recently been applied to coastal flooding and morphodynamic applications.

Publication type Article
Publication Subtype Journal Article
Title A multimodal wave spectrum-based approach for statistical downscaling of local wave climate
Series title Journal of Physical Oceanography
DOI 10.1175/JPO-D-16-0191.1
Volume 47
Year Published 2017
Language English
Publisher American Meteorological Society
Publisher location Boston, MA
Contributing office(s) Pacific Coastal and Marine Science Center
Description 12 p.
First page 375
Last page 386
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