Wind modulation by variable roughness of ocean surface

Recent results concerning transient effects of variation of short sea-surface wave roughness on near-surface turbulent wind are briefly outlined. This variation can be caused by oil, surfactants, inhomogeneous currents, internal waves, ship wakes, etc. To describe the wind parameters including surface stress and turbulent energy density, we use a direct solution of the Reynolds-type equations in the boundary-layer approximation. The solutions include a sharp and smooth roughness variation, 2-D surface variation, and a moving slick. The applicability of the theory was verified by comparison with laboratory data. Further on, the theory was applied to a problem related to the devastating tsunami near Fukushima Daichi in 2011. (C) 2018 The Authors. Published by Elsevier B.V.