Surfing is a surface water sport in which an individual, a surfer, uses a board to ride on the forward section, or face, of a moving wave of water, which usually carries the surfer towards the shore. Waves suitable for surfing are primarily found on ocean shores, but can also be found as standing waves in the open ocean, in lakes, in rivers in the form of a tidal bore, or in wave pools.
A tsunami is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions above or below water all have the potential to generate a tsunami. Unlike normal ocean waves, which are generated by wind, or tides, which are in turn generated by the gravitational pull of the Moon and the Sun, a tsunami is generated by the displacement of water from a large event.
The amplitude of a periodic variable is a measure of its change in a single period. The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplitude, which are all functions of the magnitude of the differences between the variable's extreme values. In older texts, the phase of a periodic function is sometimes called the amplitude.
In physics and many other areas of science and engineering the intensity or flux of radiant energy is the power transferred per unit area, where the area is measured on the plane perpendicular to the direction of propagation of the energy. In the SI system, it has units watts per square metre (W/m2), or kg⋅s−3 in base units. Intensity is used most frequently with waves such as acoustic waves (sound), matter waves such as electrons in electron microscopes, and electromagnetic waves such as light or radio waves, in which case the average power transfer over one period of the wave is used. Intensity can be applied to other circumstances where energy is transferred. For example, one could calculate the intensity of the kinetic energy carried by drops of water from a garden sprinkler.
In electronics, acoustics, and related fields, the waveform of a signal is the shape of its graph as a function of time, independent of its time and magnitude scales and of any displacement in time. Periodic waveforms repeat regularly at a constant period. The term can also be used for non-periodic or aperiodic signals, like chirps and pulses.
A sine wave, sinusoidal wave, or sinusoid is a periodic wave whose waveform (shape) is the trigonometric sine function. In mechanics, as a linear motion over time, this is simple harmonic motion; as rotation, it corresponds to uniform circular motion. Sine waves occur often in physics, including wind waves, sound waves, and light waves, such as monochromatic radiation. In engineering, signal processing, and mathematics, Fourier analysis decomposes general functions into a sum of sine waves of various frequencies, relative phases, and magnitudes.
Mavericks is a surfing location in northern California outside Pillar Point Harbor, just north of the town of Half Moon Bay at the village of Princeton-by-the-Sea. After a strong winter storm in the northern Pacific Ocean, waves can routinely crest at over 25 ft (8 m) and top out at over 60 ft (18 m). Routinely, waves that break can be recorded on seismometers. The break is caused by an unusually shaped underwater rock formation.
In fluid dynamics, a wind wave, or wind-generated water wave, is a surface wave that occurs on the free surface of bodies of water as a result of the wind blowing over the water's surface. The contact distance in the direction of the wind is known as the fetch. Waves in the oceans can travel thousands of kilometers before reaching land. Wind waves on Earth range in size from small ripples to waves over 30 m (100 ft) high, being limited by wind speed, duration, fetch, and water depth.
In mathematics, a rose or rhodonea curve is a sinusoid specified by either the cosine or sine functions with no phase angle that is plotted in polar coordinates. Rose curves or "rhodonea" were named by the Italian mathematician who studied them, Guido Grandi, between the years 1723 and 1728.
Edward Ryan Makuahanai Aikau was a Hawaiian lifeguard and surfer. As the first lifeguard at Waimea Bay on the island of Oahu, he saved over 500 people and became famous for surfing the big Hawaiian surf, winning several awards including the 1977 Duke Kahanamoku Invitational Surfing Championship. The Eddie Aikau Big Wave Invitational is named in his honor. He was also a crew member on the Polynesian voyaging canoe Hōkūleʻa.
Nazaré is a Portuguese town and municipality located in the Oeste region, in the historical province of Estremadura, and in the Leiria District. The municipality has a population of 14,889 in an area of 82.43 km2, while the town itself has around 10,000 inhabitants.
A swell, also sometimes referred to as ground swell, in the context of an ocean, sea or lake, is a series of mechanical waves that propagate along the interface between water and air under the predominating influence of gravity, and thus are often referred to as surface gravity waves. These surface gravity waves have their origin as wind waves, but are the consequence of dispersion of wind waves from distant weather systems, where wind blows for a duration of time over a fetch of water, and these waves move out from the source area at speeds that are a function of wave period and length. More generally, a swell consists of wind-generated waves that are not greatly affected by the local wind at that time. Swell waves often have a relatively long wavelength, as short wavelength waves carry less energy and dissipate faster, but this varies due to the size, strength, and duration of the weather system responsible for the swell and the size of the water body, and varies from event to event, and from the same event, over time. Occasionally, swells that are longer than 700m occur as a result of the most severe storms.
Peʻahi is a place on the north shore of the island of Maui in the U.S. state of Hawaii. It has lent its name to a big wave surfing break, also known as Jaws.
In fluid dynamics and nautical terminology, a breaking wave or breaker is a wave with enough energy to "break" at its peak, reaching a critical level at which linear energy transforms into wave turbulence energy with a distinct forward curve. At this point, simple physical models that describe wave dynamics often become invalid, particularly those that assume linear behaviour.
The Nazaré Canyon is a submarine canyon just off the coast of Nazaré, portuguese Oeste region, in the eastern North Atlantic Ocean. It is the largest submarine canyon in Europe, reaching depths of about 5,000 metres (16,000 ft) deep and a length of about 230 kilometres (140 mi).
In fluid dynamics, the wave height of a surface wave is the difference between the elevations of a crest and a neighboring trough. Wave height is a term used by mariners, as well as in coastal, ocean and naval engineering.
Greg Long is an American surfer from San Clemente, California. He has won the Quiksilver Big Wave Invitational, in memory of Eddie Aikau at Waimea Bay, the Red Bull Titans of Mavericks event held at Mavericks in Northern California, and the Red Bull Big Wave Africa event held at Dungeons in Hout Bay, South Africa. Additionally, he is the most decorated surfer in the Billabong XXL Global Big Wave Awards. He is widely regarded as one of the best big wave surfers in the world.
Hurricane Fernanda was the first significant hurricane threat to Hawaii since Hurricane Iniki struck in September 1992. The sixth named storm and third major hurricane of the 1993 Pacific hurricane season, Fernanda developed on August 9 off the coast of Mexico from a tropical wave. Throughout its life, it was a large system, and the hurricane reached peak winds of 145 mph (233 km/h). After weakening slightly, Fernanda restrengthened and was expected to move across the Hawaiian Islands. Instead, the hurricane slowed its forward motion and turned away from the state, although it still produced high waves along the eastern shore of the islands. Several homes were damaged, and the surf damaged coastal roads. The storm also contributed to rainfall across the state, and minor flooding occurred in Kauai. Fernanda became extratropical on August 19, and after turning to the northeast became absorbed by a cold front.
This glossary of surfing includes some of the extensive vocabulary used to describe various aspects of the sport of surfing as described in literature on the subject.[a][b] In some cases terms have spread to a wider cultural use. These terms were originally coined by people who were directly involved in the sport of surfing.
The North Shore, in the context of geography of the Island of Oʻahu, refers to the north-facing coastal area of Oʻahu between Kaʻena Point and Kahuku. The largest settlement is Haleʻiwa.
