Laboratory experiments were used to explore the influence of spatial focusing and diffraction on the evolution of unsteady, three-dimensional, deep-water wave-packets with a constant-steepness spectrum. The wave-packets were generated by thirteen independently programmed paddles and evolved to breaking near the midpoint of a 4m x 11 m test section. Detailed measurements of surface displacements...

[1] Why do ocean waves break? Understanding this important and obvious property of the ocean surface has been elusive for decades. This paper investigates causes which lead deep-water two-dimensional initially monochromatic waves to break. Individual wave steepness is found to be the single parameter which determines whether the wave will break immediately, never break or take a finite number o...

According to prevailing ideas, the formation of rogue waves and the onset of wave breaking share a common physical framework: energy focusing within nonlinear wave groups. For 2D (one horizontal spatial direction) wave packet evolution, this correspondence appears to be very close. However, the situation is less clear for 3D propagation, and in the open ocean, observed breaking of dominant wind...

From research on stratospheric dynamics there has emerged what might prove to be some useful fresh ideas about the problem of water-wave generation by wind. As pointed out in an earlier contribution (1993), water waves can be systematically amplified by two irreversible, ratchet-like mechanisms that depend on spatio-temporal inhomogeneities, such as wind gustiness and wave groupiness. Neither m...

[1] The breaking of waves is an important mechanism for a number of physical, chemical and biological processes in the ocean. Intuitively, waves break when they become too steep. Unfortunately, a general consensus on the ultimate shape of waves has not been achieved yet due to the complexity of the breaking mechanism which still remains the least understood of all processes affecting waves. To ...

The analysis of wave breaking in shallow water has been on-going for almost 150 years. Numerous research papers have been published that investigate methods to predict breaking conditions and the geometric characteristics of breaking waves. This study presents a novel, safe, and low cost method to extract breaking wave properties from irregular waves in the surf zone, using optical and in-situ ...

We test the controversial ideas about the role of corridors in fragmented animal habitats. Using simulation studies we analyze how fragmentation affects a simple prey-predator system and how the introduction of openings that connect the habitats changes the situation. Our individual based model consists of 3 levels: renewable prey food, as well as prey and predators that both have a simple econ...

Wave breaking on the surface of the ocean results in significant transfer of mass, momentum, heat and energy across the air-sea interface. However, understanding the physics of these phenomena remains a challenge, as both the measurement and simulation of the relevant processes are highly complex. Recent numerical studies have begun to investigate the air-water coupling during the breaking proc...

The flow structure in the aerated region of the roller generated by breaking waves remains a great challenge to study, with large quantities of entrained air and turbulence interactions making it very difficult to investigate in details. A number of analogies were proposed between breaking waves in deep or shallow water, tidal bores and hydraulic jumps. Many numerical models used to simulate wa...

This article investigates the synoptic characteristics of individual North Atlantic Oscillation (NAO) events by examining the daily evolution of the potential temperature field on the nominal tropopause (the 2-PVU surface). This quantity is obtained from the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis dataset for the winter seaso...