Bermuda is a British Overseas Territory in the North Atlantic Ocean. It is 1,070 km east-southeast of Cape Hatteras, North Carolina; the capital city is Hamilton. Bermuda is self-governing, with its own constitution and its own government, which enacts local laws, while the United Kingdom retains responsibility for defence and foreign relations; as of July 2018, its population is the highest of the British overseas territories. Bermuda's two largest economic sectors are offshore insurance and reinsurance, tourism. Bermuda had one of the world's highest GDP per capita for most of the 20th century; the islands have a subtropical climate and lies in the hurricane belt and thus is prone to related severe weather. The first European known to have reached Bermuda was the Spanish sea captain Juan de Bermúdez in 1505, after whom the islands are named, he claimed the islands for the Spanish Empire. Unusually, Bermuda had no indigenous population at the time of its discovery, nor at the time of the initial British settlement a century later.
Bermúdez never landed on the islands, but made two visits to the archipelago, of which he created a recognisable map. Shipwrecked Portuguese mariners are now thought to have been responsible for the 1543 inscription on Portuguese Rock. Subsequent Spanish or other European parties are believed to have released pigs there, which had become feral and abundant on the island by the time European settlement began. In 1609, the English Virginia Company permanently settled Bermuda in the aftermath of a hurricane, when the crew and passengers of the Sea Venture steered the ship onto the surrounding reef to prevent its sinking landed ashore; the island was administered as an extension of Virginia by the Company until 1614. Its spin-off, the Somers Isles Company, took over in 1615 and managed the colony until 1684. At that time, the company's charter was revoked, the English Crown took over administration; the islands became a British colony following the 1707 unification of the parliaments of Scotland and England, which created the Kingdom of Great Britain.
After 1949, when Newfoundland became part of Canada, Bermuda became the oldest remaining British overseas territory. After the return of Hong Kong to China in 1997, Bermuda became the most populous remaining dependent territory, its first capital, St. George's, was established in 1612. Bermuda was discovered in 1505 by Spanish explorer Juan de Bermúdez, it is mentioned in Legatio Babylonica, published in 1511 by historian Pedro Mártir de Anglería, was included on Spanish charts of that year. Both Spanish and Portuguese ships used the islands as a replenishment spot to take on fresh meat and water. Legends arose of spirits and devils, now thought to have stemmed from the calls of raucous birds and the loud noise heard at night from wild hogs. Combined with the frequent storm-wracked conditions and the dangerous reefs, the archipelago became known as the Isle of Devils. Neither Spain nor Portugal attempted to settle it. For the next century, the island is believed to have been visited but not settled.
After the failure of the first two English colonies in Virginia, a more determined effort was initiated by King James I of England, who granted a Royal Charter to the Virginia Company. It established a colony at Jamestown, Virginia, in 1607. Two years a flotilla of seven ships left England under the Company's Admiral, Sir George Somers, the new Governor of Jamestown, Sir Thomas Gates, with several hundred settlers and supplies to relieve the colony of Jamestown. Somers had previous experience sailing with both Sir Francis Sir Walter Raleigh; the flotilla was broken up by a storm. As the flagship, Sea Venture, was taking on water, Somers drove it onto Bermuda's reef and gained the shores safely with smaller boats – all 150 passengers and a dog survived, they stayed ten months, building two small ships to sail to Jamestown. The group of islands were claimed for the English Crown, the charter of the Virginia Company was extended to include them. In 1610, all but three of the survivors of Sea Venture sailed on to Jamestown.
Among them was John Rolfe, whose wife and child died and were buried in Bermuda. In Jamestown he married Pocahontas, a daughter of the powerful Powhatan, leader of a large confederation of about 30 Algonquian-speaking tribes in coastal Virginia. In 1612, the English began intentional settlement of Bermuda with the arrival of the ship Plough. St. George's was designated as Bermuda's first capital, it is the oldest continually inhabited English town in the New World. In 1615, the colony was passed to a new company, the Somers Isles Company, named after the admiral who saved his passengers from Sea Venture. Many Virginian place names refer to the archipelago, such as Bermuda City, Bermuda Hundred; the first English coins to circulate in North America were struck in Bermuda. The archipelago's limited land area and resources led to the creation of what may be the earliest conservation laws of the New World. In 1616 and 1620 acts were passed banning the hunting of young tortoises. In 1
United States Seventh Fleet
The Seventh Fleet is a numbered fleet of the United States Navy. It is headquartered at U. S. Fleet Activities Yokosuka, in Yokosuka, Kanagawa Prefecture, Japan, it is part of the United States Pacific Fleet. At present, it is the largest of the forward-deployed U. S. fleets, with 60 to 70 ships, 300 aircraft and 40,000 Navy and Marine Corps personnel. Its principal responsibilities are to provide joint command in natural disaster or military operations and operational command of all naval forces in the region; the Seventh Fleet was formed on 15 March 1943 in Brisbane, during the World War II, under the command of Admiral Arthur S. "Chips" Carpender. It served in the South West Pacific Area under General Douglas MacArthur; the Seventh Fleet commander served as commander of Allied naval forces in the SWPA. Most of the ships of the Royal Australian Navy were part of the fleet from 1943 to 1945 as part of Task Force 74; the Seventh Fleet—under Admiral Thomas C. Kinkaid—formed a large part of the Allied forces at the Battle of Leyte Gulf, the largest naval battle in history, in October 1944.
The Seventh Fleet fought in two of the Battle Leyte Gulf′s main actions, the Battle of Surigao Strait and the Battle off Samar. After the end of the war, the 7th Fleet moved its headquarters to China; as laid out in Operation Plan 13–45 of 26 August 1945, Kinkaid established five major task forces to manage operations in the Western Pacific: Task Force 71, the North China Force with 75 ships. After the war, on 1 January 1947, the Fleet's name was changed to Naval Forces Western Pacific. In late 1948, the Fleet moved its principal base of operations to the Philippines, where the Navy, following the war, had developed new facilities at Subic Bay and an airfield at Sangley Point. Peacetime operations of the Seventh Fleet were under the control of Commander in Chief Pacific Fleet, Admiral Arthur W. Radford, but standing orders provided that, when operating in Japanese waters or in the event of an emergency, control would pass to Commander, Naval Forces Far East, a component of General Douglas MacArthur's occupation force.
On 19 August 1949 the force was designated as United States Seventh Task Fleet. On 11 February 1950, just prior to the outbreak of the Korean War, the force assumed the name United States Seventh Fleet, which it holds today. Seventh Fleet units participated in all major operations of the Vietnamese Wars; the first Navy jet aircraft used in combat was launched from a Task Force 77 aircraft carrier on 3 July 1950. The landings at Inchon, Korea were conducted by Seventh Fleet amphibious ships; the battleships Iowa, New Jersey and Wisconsin all served as flagships for Commander, U. S. Seventh Fleet during the Korean War. During the Korean War, the Seventh Fleet consisted of Task Force 70, a maritime patrol force provided by Fleet Air Wing One and Fleet Air Wing Six, Task Force 72, the Formosa Patrol, Task Force 77, Task Force 79, a service support squadron. Over the next decade the Seventh Fleet responded to numerous crisis situations including contingency operations conducted in Laos in 1959 and Thailand in 1962.
During September 1959, in the autumn of 1960, again in January 1961, the Seventh Fleet deployed multiship carrier task forces into the South China Sea. Although the Pathet Lao and North Vietnamese supporting forces withdrew in each crisis, in the spring of 1961 their offensive appeared on the verge of overwhelming the pro-American Royal Lao Army. Once again the fleet moved into Southeast Asian waters. By the end of April 1961, most of the Seventh Fleet was deployed off the Indochinese Peninsula preparing to initiate operations into Laos; the force consisted of the Coral Sea and Midway carrier battle groups, antisubmarine support carrier Kearsarge, one helicopter carrier, three groups of amphibious ships, two submarines, three Marine battalion landing teams. At the same time, shorebased air patrol squadrons and another three Marine battalion landing teams stood ready in Okinawa and the Philippines to support the afloat force. Although the administration of President John F. Kennedy had decided against American intervention to rescue the Laotian government, Communist forces halted their advance and agreed to negotiations.
The contending Laotian factions concluded a cease-fire on 8 May 1961. In June 1963 the Seventh Fleet held'Flagpole'63,' a joint naval exercise with the Republic of Korea. Seventh Fleet represented the first official entrance of the United States into the Vietnam War, with the Gulf of Tonkin incident. Between 1950 and 1970, the U. S. Seventh Fleet was known by the tongue-in-cheek nickname "Tonkin Gulf Yacht Club" since most of the fleet's operations were conducted from the Tonkin Gulf at the time. On 12 February 1965, USS Salisbury Sound became the first U. S. Navy ship to conduct operations inside Vietnam coastal waters. Salisbury Sound set up a seadrome in Da Nang Bay and conducted seaplane patrols in support of Operation Flaming Dart, the bombing of North Vietnamese army camps. Operating from Yankee Station off the north coast of Vietnam and the aptly-named Dixie Station off the south coast of Vietnam in the South China Sea,Seventh Fleet was organized into a series of task forces, often
Luzon is the largest and most populous island in the Philippines. It is ranked 15th largest in the world by land area. Located in the northern region of the archipelago, it is the economic and political center of the nation, being home to the country's capital city, Manila, as well as Quezon City, the country's most populous city. With a population of 53 million as of 2015, it is the fourth most populous island in the world containing 52.5% of the country's total population. Luzon may refer to one of the three primary island groups in the country; as such, it includes the Luzon mainland, the Batanes and Babuyan groups of islands to the north, Polillo Islands to the east, the outlying islands of Catanduanes, Masbate, Romblon and Palawan, among others, to the south. The name Luzon is thought to derive from the Tagalog word lusong, a large wooden mortar used in dehusking rice. Luzon was inhabited by Negrito people before Austronesians from Taiwan displaced them; the Austronesian groups were divided further into two types of nations.
Highland civilizations were based in the mountains and had built up plutocracies based on agriculture, such as the Igorot Society, responsible for building the Banaue Rice Terraces. Meanwhile, maritime states were split among Hindu-Buddhist kingdoms, Muslim principalities, ethnoreligious tribes, who had trading connections with Borneo, Java, India, Korea and China before the Spanish established their rule. From just before the first millennium, the Tagalog and Kapampangan peoples of south and central Luzon had established several major coastal polities, most notable among them those of Maynila and Namayan; the Laguna Copperplate Inscription, the first Philippine document written in 900AD, names places in and around Manila Bay as well as Medan in Indonesia. These kingdoms were based on leases between village rulers and landlords or Rajahs, to whom tributes and taxes were levied; these kingdoms were coastal thalassocracies based on trade with neighboring Asian political entities at that time.
There was a Sino-Buddhist country in nearby Mindoro called the country of Ma-i. According to sources at the time, the trade in large native Ruson-tsukuri clay jars used for storing green tea and rice wine with Japan flourished in the 12th century, local Tagalog and Pangasinense potters had marked each jar with Baybayin letters denoting the particular urn used and the kiln the jars were manufactured in. Certain kilns were renowned over prices depended on the reputation of the kiln. Of this flourishing trade, the Burnay jars of Ilocos are the only large clay jar manufactured in Luzon today with origins from this time. During the 1300s, the Javanese-centered Hindu empire of Majapahit ruled over Luzon as recorded in the epic poem Nagarakretagama, which stated that they had colonies in the Philippines at Saludong and Solot; the kingdoms of Luzon regained independence from Majapahit after the Battle of Manila and Sulu reestablished independence and in vengeance, assaulted the Majapahit province of Poni before a fleet from the capital drove them out.
The Yongle Emperor instituted a Chinese Governor on Luzon during Zheng He's voyages and appointed Ko Ch'a-lao to that position in 1405. China had vassals among the leaders in the archipelago. China attained ascendancy in trade with the area in Yongle's reign. Afterwards, some parts of Luzon were Islamized when the former Majapahit province of Poni broke free, converted to Islam, imported an Arab prince from Saudi Arabia, in the person of Sharif Ali, became the Sultanate of Brunei, a nation that expanded its realms from Borneo to the Philippines and set up the Kingdom of Maynila as its puppet-state as well as incorporate the newly converted Sultanate of Sulu by a royal marriage. However, other kingdoms resisted Islam, like the Wangdom of Pangasinan which had remained a tributary state to China and was a Sinified kingdom which maintained trade with Japan. In the 1500s, people from Luzon were called Lucoes and they established many overseas communities within the Indo-Pacific and were employed in trading and military campaigns across Southeast Asia.
The Portuguese were the first European explorers who recorded it in their charts as Luçonia or Luçon and inhabitants were called Luçoes. Edmund Roberts, who visited Luzon in the early 19th century, wrote that Luzon was "discovered" in 1521. Many people from Luzon had active-employment in Portuguese Malacca. Lucoes such as the Luzon spice magnate Regimo de Raja, based in Malacca, was influential and the Portuguese appointed him as Temenggong or a governor and chief general responsible for overseeing of maritime trade, at Malacca; as Temenggung, he was the head of an armada which traded and protected commerce between the Indian Ocean, the Strait of Malacca, the South China Sea, the medieval maritime principalities of the Philippines. His father and wife carried on his maritime trading business after his death. Another important Malacca trader was Curia de Raja who hailed from Luzon; the "surname" of "de Raja" or "diraja" could indicate that Regimo and Curia, their families, were of noble or royal descent as the term is an abbreviation of Sanskrit adiraja.
Pinto noted that there were a number of Lucoes in the Islamic fleets that went to battle with the Portuguese in the Philippines during the 16th century. The Sultan of Aceh gave one of them the task of holding Aru in 1540. Pinto says one was named leader of the Malays remaining in the Moluccas Islands after the
Laying the keel or laying down is the formal recognition of the start of a ship's construction. It is marked with a ceremony attended by dignitaries from the shipbuilding company and the ultimate owners of the ship. Keel laying is one of the four specially celebrated events in the life of a ship. In earlier times, the event recognized as the keel laying was the initial placement of the central timber making up the backbone of a vessel, called the keel; as steel ships replaced wooden ones, the central timber gave way to a central steel beam. Modern ships are now built in a series of pre-fabricated, complete hull sections rather than being built around a single keel; the event recognized as the keel laying is the first joining of modular components, or the lowering of the first module into place in the building dock. It is now called "keel authentication", is the ceremonial beginning of the ship's life, although some modules may have been started months before that stage of construction. Keel-related traditions from the times of wooden ships are said to bring luck to the ship during construction and to the captain and crew during her life.
They include placing a newly minted coin under the keel and constructing the ship over it, having the youngest apprentice place the coin, when the ship is finished, presenting the owners with the oak block on which the keel is laid. The tradition of the placement of coins derives from the mast stepping custom of placing coins under the mast and is believed to date back to Ancient Greece or Ancient Rome and were intended to "pay the ferryman" to convey the souls of the dead across the River Styx should the ship sink; the first milestone in the history of a ship is the simple ceremony that marks the laying of the keel. Invitations to the ceremony are issued by shipyard officials, the ceremony is conducted by them; the builder may be the president of a private company. The ship's prospective name, without the "USS", is mentioned in the invitation.
Boston is the capital and most populous city of the Commonwealth of Massachusetts in the United States. The city proper covers 48 square miles with an estimated population of 685,094 in 2017, making it the most populous city in New England. Boston is the seat of Suffolk County as well, although the county government was disbanded on July 1, 1999; the city is the economic and cultural anchor of a larger metropolitan area known as Greater Boston, a metropolitan statistical area home to a census-estimated 4.8 million people in 2016 and ranking as the tenth-largest such area in the country. As a combined statistical area, this wider commuting region is home to some 8.2 million people, making it the sixth-largest in the United States. Boston is one of the oldest cities in the United States, founded on the Shawmut Peninsula in 1630 by Puritan settlers from England, it was the scene of several key events of the American Revolution, such as the Boston Massacre, the Boston Tea Party, the Battle of Bunker Hill, the Siege of Boston.
Upon gaining U. S. independence from Great Britain, it continued to be an important port and manufacturing hub as well as a center for education and culture. The city has expanded beyond the original peninsula through land reclamation and municipal annexation, its rich history attracts many tourists, with Faneuil Hall alone drawing more than 20 million visitors per year. Boston's many firsts include the United States' first public park, first public or state school and first subway system; the Boston area's many colleges and universities make it an international center of higher education, including law, medicine and business, the city is considered to be a world leader in innovation and entrepreneurship, with nearly 2,000 startups. Boston's economic base includes finance and business services, information technology, government activities. Households in the city claim the highest average rate of philanthropy in the United States; the city has one of the highest costs of living in the United States as it has undergone gentrification, though it remains high on world livability rankings.
Boston's early European settlers had first called the area Trimountaine but renamed it Boston after Boston, England, the origin of several prominent colonists. The renaming on September 7, 1630, was by Puritan colonists from England who had moved over from Charlestown earlier that year in quest for fresh water, their settlement was limited to the Shawmut Peninsula, at that time surrounded by the Massachusetts Bay and Charles River and connected to the mainland by a narrow isthmus. The peninsula is thought to have been inhabited as early as 5000 BC. In 1629, the Massachusetts Bay Colony's first governor John Winthrop led the signing of the Cambridge Agreement, a key founding document of the city. Puritan ethics and their focus on education influenced its early history. Over the next 130 years, the city participated in four French and Indian Wars, until the British defeated the French and their Indian allies in North America. Boston was the largest town in British America until Philadelphia grew larger in the mid-18th century.
Boston's oceanfront location made it a lively port, the city engaged in shipping and fishing during its colonial days. However, Boston stagnated in the decades prior to the Revolution. By the mid-18th century, New York City and Philadelphia surpassed Boston in wealth. Boston encountered financial difficulties as other cities in New England grew rapidly. Many of the crucial events of the American Revolution occurred near Boston. Boston's penchant for mob action along with the colonists' growing distrust in Britain fostered a revolutionary spirit in the city; when the British government passed the Stamp Act in 1765, a Boston mob ravaged the homes of Andrew Oliver, the official tasked with enforcing the Act, Thomas Hutchinson the Lieutenant Governor of Massachusetts. The British sent two regiments to Boston in 1768 in an attempt to quell the angry colonists; this did not sit well with the colonists. In 1770, during the Boston Massacre, the army killed several people in response to a mob in Boston.
The colonists compelled the British to withdraw their troops. The event was publicized and fueled a revolutionary movement in America. In 1773, Britain passed the Tea Act. Many of the colonists saw the act as an attempt to force them to accept the taxes established by the Townshend Acts; the act prompted the Boston Tea Party, where a group of rebels threw an entire shipment of tea sent by the British East India Company into Boston Harbor. The Boston Tea Party was a key event leading up to the revolution, as the British government responded furiously with the Intolerable Acts, demanding compensation for the lost tea from the rebels; this led to the American Revolutionary War. The war began in the area surrounding Boston with the Battles of Concord. Boston itself was besieged for a year during the Siege of Boston, which began on April 19, 1775; the New England militia impeded the movement of the British Army. William Howe, 5th Viscount Howe the commander-in-chief of the British forces in North America, led the British army in the siege.
On June 17, the British captured the Charlestown peninsula in Boston, during the Battle of Bunker Hill. The British army outnumbered the militia stationed there, but it was a Py
New Orleans is a consolidated city-parish located along the Mississippi River in the southeastern region of the U. S. state of Louisiana. With an estimated population of 393,292 in 2017, it is the most populous city in Louisiana. A major port, New Orleans is considered an economic and commercial hub for the broader Gulf Coast region of the United States. New Orleans is world-renowned for its distinct music, Creole cuisine, unique dialect, its annual celebrations and festivals, most notably Mardi Gras; the historic heart of the city is the French Quarter, known for its French and Spanish Creole architecture and vibrant nightlife along Bourbon Street. The city has been described as the "most unique" in the United States, owing in large part to its cross-cultural and multilingual heritage. Founded in 1718 by French colonists, New Orleans was once the territorial capital of French Louisiana before being traded to the United States in the Louisiana Purchase of 1803. New Orleans in 1840 was the third-most populous city in the United States, it was the largest city in the American South from the Antebellum era until after World War II.
The city's location and flat elevation have made it vulnerable to flooding. State and federal authorities have installed a complex system of levees and drainage pumps in an effort to protect the city. New Orleans was affected by Hurricane Katrina in 2005, which resulted in flooding more than 80% of the city, thousands of deaths, so much displacement because of damaged communities and lost housing as to cause a population decline of over 50%. Since Katrina, major redevelopment efforts have led to a rebound in the city's population. Concerns about gentrification, new residents buying property in closely knit communities, displacement of longtime residents have been expressed; the city and Orleans Parish are coterminous. As of 2017, Orleans Parish is the third most-populous parish in Louisiana, behind East Baton Rouge Parish and neighboring Jefferson Parish; the city and parish are bounded by St. Tammany Parish and Lake Pontchartrain to the north, St. Bernard Parish and Lake Borgne to the east, Plaquemines Parish to the south, Jefferson Parish to the south and west.
The city anchors the larger New Orleans metropolitan area, which had an estimated population of 1,275,762 in 2017. It is the most populous metropolitan area in Louisiana and the 46th-most populated MSA in the United States; the city is named after the Duke of Orleans, who reigned as Regent for Louis XV from 1715 to 1723. It has many illustrative nicknames: Crescent City alludes to the course of the Lower Mississippi River around and through the city; the Big Easy was a reference by musicians in the early 20th century to the relative ease of finding work there. It may have originated in the Prohibition era, when the city was considered one big speakeasy due to the government's inability to control alcohol sales, in open violation of the 18th Amendment; the City that Care Forgot has been used since at least 1938, refers to the outwardly easy-going, carefree nature of the residents. La Nouvelle-Orléans was founded in the Spring of 1718 by the French Mississippi Company, under the direction of Jean-Baptiste Le Moyne de Bienville, on land inhabited by the Chitimacha.
It was named for Philippe II, Duke of Orléans, Regent of the Kingdom of France at the time. His title came from the French city of Orléans; the French colony was ceded to the Spanish Empire in the Treaty of Paris, following France's defeat by Great Britain in the Seven Years' War. During the American Revolutionary War, New Orleans was an important port for smuggling aid to the rebels, transporting military equipment and supplies up the Mississippi River. Beginning in the 1760s, Filipinos began to settle around New Orleans. Bernardo de Gálvez y Madrid, Count of Gálvez launched a southern campaign against the British from the city in 1779. Nueva Orleans remained under Spanish control until 1803, when it reverted to French rule. Nearly all of the surviving 18th-century architecture of the Vieux Carré dates from the Spanish period, notably excepting the Old Ursuline Convent. Napoleon sold Louisiana to the United States in the Louisiana Purchase in 1803. Thereafter, the city grew with influxes of Americans, French and Africans.
Immigrants were Irish, Germans and Italians. Major commodity crops of sugar and cotton were cultivated with slave labor on nearby large plantations. Thousands of refugees from the 1804 Haitian Revolution, both whites and free people of color, arrived in New Orleans. While Governor Claiborne and other officials wanted to keep out additional free black people, the French Creoles wanted to increase the French-speaking population; as more refugees were allowed into the Territory of Orleans, Haitian émigrés who had first gone to Cuba arrived. Many of the white Francophones had been deported by officials in Cuba in retaliation for Bonapartist schemes. Nearly 90 percent of these immigrants settled in New Orleans; the 1809 migration brought 2,731 whites, 3,102 free people of color, 3,226 slaves of African descent, doubling the city's population. The city became a greater proportion than Charleston, South Carolina's 53 percent. During the final campaign of the War of 1812, the British sent a force of 11,000 in a
A tropical cyclone is a rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, 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, tropical storm, cyclonic storm, tropical depression, cyclone. A hurricane is a tropical cyclone that occurs in the Atlantic Ocean and northeastern Pacific Ocean, a typhoon occurs in the northwestern Pacific Ocean. "Cyclone" refers to their winds moving in a circle, whirling round their central clear eye, with their winds blowing counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. The opposite direction of circulation is due to the Coriolis effect. Tropical cyclones form over large bodies of warm water, they derive their energy through the evaporation of water from the ocean surface, which recondenses into clouds and rain when moist air rises and cools to saturation.
This energy source differs from that of mid-latitude cyclonic storms, such as nor'easters and European windstorms, which are fueled by horizontal temperature contrasts. Tropical cyclones are between 100 and 2,000 km in diameter; the strong rotating winds of a tropical cyclone are a result of the conservation of angular momentum imparted by the Earth's rotation as air flows inwards toward the axis of rotation. As a result, they form within 5° of the equator. Tropical cyclones are unknown in the South Atlantic due to a strong wind shear and a weak Intertropical Convergence Zone; the African easterly jet and areas of atmospheric instability which give rise to cyclones in the Atlantic Ocean and Caribbean Sea, along with the Asian monsoon and Western Pacific Warm Pool, are features of the Northern Hemisphere and Australia. Coastal regions are vulnerable to the impact of a tropical cyclone, compared to inland regions; the primary energy source for these storms is warm ocean waters, therefore these forms are strongest when over or near water, weaken quite over land.
Coastal damage may be caused by strong winds and rain, high waves, storm surges, the potential of spawning tornadoes. Tropical cyclones draw in air from a large area—which can be a vast area for the most severe cyclones—and concentrate the precipitation of the water content in that air into a much smaller area; this continual replacement of moisture-bearing air by new moisture-bearing air after its moisture has fallen as rain, which may cause heavy rain and river flooding up to 40 kilometres from the coastline, far beyond the amount of water that the local atmosphere holds at any one time. Though their effects on human populations are devastating, tropical cyclones can relieve drought conditions, they carry heat energy away from the tropics and transport it toward temperate latitudes, which may play an important role in modulating regional and global climate. Tropical cyclones are areas of low pressure in the troposphere, with the largest pressure perturbations occurring at low altitudes near the surface.
On Earth, the pressures recorded at the centers of tropical cyclones are among the lowest observed at sea level. The environment near the center of tropical cyclones is warmer than the surroundings at all altitudes, thus they are characterized as "warm core" systems; the near-surface wind field of a tropical cyclone is characterized by air rotating around a center of circulation while flowing radially inwards. At the outer edge of the storm, air may be nearly calm; as air flows radially inward, it begins to rotate cyclonically in order to conserve angular momentum. At an inner radius, air begins to ascend to the top of the troposphere; this radius is coincident with the inner radius of the eyewall, has the strongest near-surface winds of the storm. Once aloft, air flows away from the storm's center; the mentioned processes result in a wind field, nearly axisymmetric: Wind speeds are low at the center, increase moving outwards to the radius of maximum winds, decay more with radius to large radii.
However, the wind field exhibits additional spatial and temporal variability due to the effects of localized processes, such as thunderstorm activity and horizontal flow instabilities. In the vertical direction, winds are strongest near the surface and decay with height within the troposphere. At the center of a mature tropical cyclone, air sinks rather than rises. For a sufficiently strong storm, air may sink over a layer deep enough to suppress cloud formation, thereby creating a clear "eye". Weather in the eye is calm and free of clouds, although the sea may be violent; the eye is circular in shape, is 30–65 km in diameter, though eyes as small as 3 km and as large as 370 km have been observed. The cloudy outer edge of the eye is called the "eyewall"; the eyewall expands outward with height, resembling an arena foo