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The fetch, also called the fetch length, is the length of water over which a given wind has blown. Fetch is used in geography and meteorology and its effects are usually associated with sea state and when it reaches shore it is the main factor that creates storm surge which leads to coastal erosion and flooding. It also plays a large part in longshore drift as well.
Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the Sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space. Winds are commonly classified by their spatial scale, their speed, the types of forces that cause them, the regions in which they occur, and their effect. The strongest observed winds on a planet in the Solar System occur on Neptune and Saturn. Winds have various aspects, an important one being its velocity ; another the density of the gas involved; another its energy content or wind energy. Wind is also a great source of transportation for seeds and small birds; with time things can travel thousands of miles in the wind.
Geography is a field of science devoted to the study of the lands, features, inhabitants, and phenomena of the Earth and planets. The first person to use the word γεωγραφία was Eratosthenes. Geography is an all-encompassing discipline that seeks an understanding of Earth and its human and natural complexities—not merely where objects are, but also how they have changed and come to be.
Meteorology is a branch of the atmospheric sciences which includes atmospheric chemistry and atmospheric physics, with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw modest progress in the field after weather observation networks were formed across broad regions. Prior attempts at prediction of weather depended on historical data. It was not until after the elucidation of the laws of physics and more particularly, the development of the computer, allowing for the automated solution of a great many equations that model the weather, in the latter half of the 20th century that significant breakthroughs in weather forecasting were achieved. An important domain of weather forecasting is marine weather forecasting as it relates to maritime and coastal safety, in which weather effects also include atmospheric interactions with large bodies of water.
Fetch length, along with the wind speed (wind strength), determines the size (sea state) of waves produced. The wind direction is considered constant. The longer the fetch and the faster the wind speed, the more wind energy is imparted to the water surface and the larger the resulting sea state will be.
In oceanography, sea state is the general condition of the free surface on a large body of water—with respect to wind waves and swell—at a certain location and moment. A sea state is characterized by statistics, including the wave height, period, and power spectrum. The sea state varies with time, as the wind conditions or swell conditions change. The sea state can either be assessed by an experienced observer, like a trained mariner, or through instruments like weather buoys, wave radar or remote sensing satellites.
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Surfing is a surface water sport in which the wave rider, referred to as a surfer, rides on the forward or face of a moving wave, which usually carries the surfer towards the shore. Waves suitable for surfing are primarily found in the ocean, but can also be found in lakes or rivers in the form of a standing wave or tidal bore. However, surfers can also utilize artificial waves such as those from boat wakes and the waves created in artificial wave pools.
A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles. The particles can also be biological in origin, such as mollusc shells or coralline algae.
Lake-effect snow is produced during cooler atmospheric conditions when a cold air mass moves across long expanses of warmer lake water. The lower layer of air, heated up by the lake water, picks up water vapor from the lake and rises up through the colder air above; the vapor then freezes and is deposited on the leeward (downwind) shores.
A storm is any disturbed state of an environment or in an astronomical body's atmosphere especially affecting its surface, and strongly implying severe weather. It may be marked by significant disruptions to normal conditions such as strong wind, tornadoes, hail, thunder and lightning, heavy precipitation, heavy freezing rain, strong winds, or wind transporting some substance through the atmosphere as in a dust storm, blizzard, sandstorm, etc.
Wind shear, sometimes referred to as wind gradient, is a difference in wind speed or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizontal wind shear. Vertical wind shear is a change in wind speed or direction with change in altitude. Horizontal wind shear is a change in wind speed with change in lateral position for a given altitude.
A hypercane is a hypothetical class of extreme tropical cyclone that could form if ocean temperatures reached 50 °C (122 °F), which is 15 °C (27 °F) warmer than the warmest ocean temperature ever recorded. Such an increase could be caused by a large asteroid or comet impact, a large supervolcanic eruption, a large submarine flood basalt, or extensive global warming. There is some speculation that a series of hypercanes resulting from an impact by a large asteroid or comet contributed to the demise of the non-avian dinosaurs. The hypothesis was created by Kerry Emanuel of MIT, who also coined the term.
A seiche is a standing wave in an enclosed or partially enclosed body of water. Seiches and seiche-related phenomena have been observed on lakes, reservoirs, swimming pools, bays, harbours and seas. The key requirement for formation of a seiche is that the body of water be at least partially bounded, allowing the formation of the standing wave.
The 1938 New England Hurricane was one of the deadliest and most destructive tropical cyclones to strike Long Island, New York, and New England. The storm formed near the coast of Africa on September 9, becoming a Category 5 hurricane on the Saffir-Simpson Hurricane Scale, before making landfall as a Category 3 hurricane on Long Island on September 21. It is estimated that the hurricane killed 682 people, damaged or destroyed more than 57,000 homes, and caused property losses estimated at $306 million. Damaged trees and buildings were still seen in the affected areas as late as 1951. It remains the most powerful and deadliest hurricane in recorded New England history, perhaps eclipsed in landfall intensity only by the Great Colonial Hurricane of 1635.
A storm surge, storm flood, tidal surge or storm tide is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low pressure weather systems, the severity of which is affected by the shallowness and orientation of the water body relative to storm path, as well as the timing of tides. Most casualties during tropical cyclones occur as the result of storm surges. It is a measure of the rise of water beyond what would be expected by the normal movement related to tides.
In fluid dynamics, wind waves, or wind-generated waves, are surface waves that occur on the free surface of bodies of water. They result from the wind blowing over an area of fluid surface. Waves in the oceans can travel thousands of miles before reaching land. Wind waves on Earth range in size from small ripples, to waves over 100 ft (30 m) high.
Hurricane Katrina's winds and storm surge reached the Mississippi coastline on the morning of August 29, 2005. beginning a two-day path of destruction through central Mississippi; by 10 a.m. CDT on August 29, 2005, the eye of Katrina began traveling up the entire state, only slowing from hurricane-force winds at Meridian near 7 p.m. and entering Tennessee as a tropical storm. Many coastal towns of Mississippi had already been obliterated, in a single night. Hurricane-force winds reached coastal Mississippi by 2 a.m. and lasted over 17 hours, spawning 11 tornadoes and a 28-foot storm surge flooding 6–12 miles (10–19 km) inland. Many, unable to evacuate, survived by climbing to attics or rooftops, or swimming to higher buildings and trees. The worst property damage from Katrina occurred in coastal Mississippi, where all towns flooded over 90% in hours, and waves destroyed many historic buildings, with others gutted to the 3rd story. Afterward, 238 people died in Mississippi, and all counties in Mississippi were declared disaster areas, 49 for full federal assistance. Regulations were changed later for emergency centers and casinos. The emergency command centers were moved higher because all 3 coastal centers flooded at 30 ft (9 m) above sea level. Casinos were allowed on land rather than limited to floating casino barges as in 2005.
A 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 and thus are often referred to as surface gravity waves. These series of surface gravity waves are not wind waves, which are generated by the immediate local wind, but instead are generated by distant weather systems, where wind blows for a duration of time over a fetch of water. More generally, a swell consists of wind-generated waves that are not—or are hardly—affected by the local wind at that time. Swell waves often have a long wavelength, 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. Swell wavelength also varies from event to event. Occasionally, swells which are longer than 700 m occur as a result of the most severe storms. Swells have a narrower range of frequencies and directions than locally generated wind waves, because swell waves have dispersed from their generation area, have dissipated and therefore lost an amount of randomness, taking on a more defined shape and direction. Swell direction is the direction from which the swell is coming. It is measured in degrees, and often referred to in general directions, such as a NNW or SW swell.
Typhoon Vera, also known as the Isewan Typhoon, was an exceptionally intense tropical cyclone that struck Japan in September 1959, becoming the strongest and deadliest typhoon on record to make landfall on the country. The storm's intensity resulted in damage of unparalleled severity and extent, and was a major setback to the Japanese economy, which was still recovering from World War II. In the aftermath of Vera, Japan's disaster management and relief systems were significantly reformed, and the typhoon's effects would set a benchmark for future storms striking the country.
Hurricane Katrina was an extremely destructive Category 5 hurricane that affected the majority of the Gulf Coast. Its damaging trek began on August 23, 2005 when it originated as Tropical Depression Twelve near the Bahamas. The next day, the tropical depression strengthened to a tropical storm, and was named Katrina; it proceeded to make landfall on the southern tip of the U.S. state of Florida as a minimal hurricane.
In fluid dynamics, a breaking wave is a wave whose amplitude reaches a critical level at which some process can suddenly start to occur that causes large amounts of wave energy to be transformed into turbulent kinetic energy. At this point, simple physical models that describe wave dynamics often become invalid, particularly those that assume linear behaviour.
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. Depending on its location and strength, a tropical cyclone is referred to by different names, including hurricane, typhoon, tropical storm, cyclonic storm, tropical depression, and simply cyclone. A hurricane is a tropical cyclone that occurs in the Atlantic Ocean and northeastern Pacific Ocean, and a typhoon occurs in the northwestern Pacific Ocean; in the south Pacific or Indian Ocean, comparable storms are referred to simply as "tropical cyclones" or "severe cyclonic storms".
Infragravity waves are surface gravity waves with frequencies lower than the wind waves – consisting of both wind sea and swell – thus corresponding with the part of the wave spectrum lower than the frequencies directly generated by forcing through the wind.
Coastal flooding occurs when normally dry, low-lying land is flooded by seawater. The extent of coastal flooding is a function of the elevation inland flood waters penetrate which is controlled by the topography of the coastal land exposed to flooding. The seawater can flood the land via from several different paths:
This glossary of meteorology is a list of terms and concepts relevant to meteorology and the atmospheric sciences, their sub-disciplines, and related fields.