数値シミュレーションで強い海流が表面波を減衰させることを解明(Computer simulations show strong ocean currents reduce size of surface waves)

2026-02-05 ロードアイランド大学(URI)

ロードアイランド大学の研究チームは、数値シミュレーションを用いて、強い海流が海面波の高さや大きさを低下させる仕組みを明らかにした。従来、強風時には波が成長すると考えられてきたが、本研究では、表層を流れる強い海流が存在すると、波のエネルギーが拡散・分散され、結果として波高や波長が抑制されることが示された。高解像度の計算モデルにより、風、波、海流の相互作用を詳細に解析した結果、海流が波の発達過程を根本的に変える可能性が示唆された。これらの知見は、海洋予測モデルの精度向上に寄与するだけでなく、航海の安全確保や沿岸防災、洋上エネルギー施設の設計にも重要な影響を与えると期待される。

数値シミュレーションで強い海流が表面波を減衰させることを解明(Computer simulations show strong ocean currents reduce size of surface waves)
Using a high-performance computer, the research team generated models to show how storm-driven currents affect wave height and dominant wave period. (URI images courtesy of Isaac Ginis)

<関連情報>

熱帯低気圧によって発生する表面波に対する海流の影響 Impact of Ocean Currents on Surface Waves Generated by Tropical Cyclone

Angelos Papandreou,Isaac Ginis, and Tetsu Hara
Journal of Physical Oceanography  Published:06 Jan 2026
DOI:https://doi.org/10.1175/JPO-D-25-0137.1

Abstract

Accurate surface wave predictions under tropical cyclones require a coupled ocean–wave model, as the wave field can be strongly influenced by surface currents. In this study, the WAVEWATCH III wave model, coupled with the Modular Ocean Model 6, is used to examine the impacts of surface currents on deep-water waves forced by idealized tropical cyclones of varying size, intensity, and translation speed. The ocean model uses a mixing scheme that explicitly includes wave-induced Langmuir turbulence enhancement, resulting in reduced surface Eulerian currents that are more consistent with observations. The surface current introduced in the wave model is the sum of the surface Eulerian current and the enhancement of the dominant wave group velocity due to the nonlinear interaction with coexisting waves. Results across all cases show that maximum significant wave height is substantially overestimated, by up to ∼9%, when the current effect is omitted. Wave simulations are also sensitive to how the surface current is specified, underscoring the importance of using an accurate upper-ocean mixing scheme and incorporating group velocity enhancement by coexisting waves into the wave model. Analysis further reveals that the wave height reduction arises primarily because dominant wave packets propagate faster and spend less time under strong wind. These findings demonstrate that proper representation of surface currents is critical for improving the accuracy of wave forecasts in tropical cyclone conditions.

1702地球物理及び地球化学
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