1.
Sailing ship
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A modern sailing ship or sailship is any large wind-powered vessel. Traditionally a sailing ship is a vessel that carries three or more masts with square sails on each. Large sailing vessels that are not ship-rigged may be more referred to by their sail rig, such as schooner, barque, brig. There are many different types of sailing ships, but they all have certain basic things in common, every sailing ship has a hull, rigging and at least one mast to hold up the sails that use the wind to power the ship. The crew who sail a ship are called sailors or hands and they take turns to take the watch, the active managers of the ship and her performance for a period. Watches are traditionally four hours long, some sailing ships use traditional ships bells to tell the time and regulate the watch system, with the bell being rung once for every half hour into the watch and rung eight times at watch end. A severe storm could lead to shipwreck, and the loss of all hands, Sailing ships are limited in their maximum size compared to ships with heat engines, so economies of scale are also limited. The heaviest sailing ships never exceeded 14,000 tons displacement, there are many types of sailing ships, mostly distinguished by their rigging, hull, keel, or number and configuration of masts. There are also types of smaller sailboats not listed here. The steam power was used to drive the winches, hoists, a similar ship Kruzenshtern, a very large sailing vessel without mechanical assists, had a crew of 257 men, compared to the Preussen, which required only 48 men. In 2006, automated control had been taken to the point where sails could be operated by one using a central control unit. The DynaRig technology was first developed in the 1960s in Germany by W. Prolls as an alternative for commercial ships to prepare for a possible future energy crisis. The technology is a version of the same type of sail used by the Preussen. The main difference is that the yards do not swing around a fixed mast but are attached to a rotating mast. DynaRig along with extensive computerization was used in the proof-of-concept Maltese Falcon to enable it to be sailed with no crew aloft, as of 2013, with increasing restrictions on use of bunker fuel, attempts were underway to develop hybrid sailing ships using automated sail and alternative fuels. Tall ship Rigging Sail-plan List of large sailing vessels Cruising Shipbuilding, the History of a Ship from Her Cradle to Her Grave, With a Short Account of Modern Steamships and Torpedoes. The sailing-ship, six years of history. Media related to Sailing ships at Wikimedia Commons
2.
Portugal
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Portugal, officially the Portuguese Republic, is a country on the Iberian Peninsula in Southwestern Europe. It is the westernmost country of mainland Europe, to the west and south it is bordered by the Atlantic Ocean and to the east and north by Spain. The Portugal–Spain border is 1,214 kilometres long and considered the longest uninterrupted border within the European Union, the republic also includes the Atlantic archipelagos of the Azores and Madeira, both autonomous regions with their own regional governments. The territory of modern Portugal has been settled, invaded. The Pre-Celts, Celts, Carthaginians and the Romans were followed by the invasions of the Visigothic, in 711 the Iberian Peninsula was invaded by the Moors, making Portugal part of Muslim Al Andalus. Portugal was born as result of the Christian Reconquista, and in 1139, Afonso Henriques was proclaimed King of Portugal, in the 15th and 16th centuries, Portugal established the first global empire, becoming one of the worlds major economic, political and military powers. Portugal monopolized the trade during this time, and the Portuguese Empire expanded with military campaigns led in Asia. After the 1910 revolution deposed the monarchy, the democratic but unstable Portuguese First Republic was established, democracy was restored after the Portuguese Colonial War and the Carnation Revolution in 1974. Shortly after, independence was granted to almost all its overseas territories, Portugal has left a profound cultural and architectural influence across the globe and a legacy of over 250 million Portuguese speakers today. Portugal is a country with a high-income advanced economy and a high living standard. It is the 5th most peaceful country in the world, maintaining a unitary semi-presidential republican form of government and it has the 18th highest Social Progress in the world, putting it ahead of other Western European countries like France, Spain and Italy. Portugal is a pioneer when it comes to drug decriminalization, as the nation decriminalized the possession of all drugs for use in 2001. The early history of Portugal is shared with the rest of the Iberian Peninsula located in South Western Europe, the name of Portugal derives from the joined Romano-Celtic name Portus Cale. Other influences include some 5th-century vestiges of Alan settlements, which were found in Alenquer, Coimbra, the region of present-day Portugal was inhabited by Neanderthals and then by Homo sapiens, who roamed the border-less region of the northern Iberian peninsula. These were subsistence societies that, although they did not establish prosperous settlements, neolithic Portugal experimented with domestication of herding animals, the raising of some cereal crops and fluvial or marine fishing. Chief among these tribes were the Calaicians or Gallaeci of Northern Portugal, the Lusitanians of central Portugal, the Celtici of Alentejo, a few small, semi-permanent, commercial coastal settlements were also founded in the Algarve region by Phoenicians-Carthaginians. Romans first invaded the Iberian Peninsula in 219 BC, during the last days of Julius Caesar, almost the entire peninsula had been annexed to the Roman Republic. The Carthaginians, Romes adversary in the Punic Wars, were expelled from their coastal colonies and it suffered a severe setback in 150 BC, when a rebellion began in the north
3.
Lateen
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A lateen or latin-rig is a triangular sail set on a long yard mounted at an angle on the mast, and running in a fore-and-aft direction. Dating back to Roman navigation, the lateen became the sail of the Age of Discovery. It is common in the Mediterranean, the upper Nile River, and the parts of the Indian Ocean. The lateen is used today in a different form on small recreational boats like the Sailfish and Sunfish. The earliest fore-and-aft rig was the spritsail, appearing in the 2nd century BC in the Aegean Sea on small Greek craft, one theory is that the lateen sail originated during the early Roman empire in the Mediterranean Sea. It evolved out of the dominant square rig by setting the sails more fore-and-aft – along the line of the keel – rather than athwartship, while tailoring the luff and leech. The theory of Roman origin for lateen was begun with Lynn White, John M. H. Brindley.25 The original passage cited from Caesarus is, according to Brindley, no more than an allusion, ‘tres naves, quas Latenas vocant, majores, plenas tritico direxerunt’. The assumption is that labelling these three wheat ships ‘latines’ means that they had lateen sails, there is also reason to doubt Sottas’s interpretation of Procopius’ claim – that three ships of Justinian’s fleet in 533 deployed lateen sails. That the triangular sails refer to triangular top sails, which were standard gear on Roman square-rigged ships after 50 ad’, second, White’s claim that the lateen sail was deployed on a European ship in 880 is problematic. We know that the Persians were sailing to India and beyond via the Persian Gulf from the third, and by the mid-seventh century the Muslims were sailing the length of the Indian Ocean. But even if the Romans had invented the lateen sail, it is important to note that after 50 ce there is no evidence of refinement or further development of sails and rigging. Based on this theory, the lateen sail originated in the Near East, most likely in Persia or Arabia and these sailors were likely responsible for introducing the lateen sails and large three-masted merchant vessels to the Mediterranean. According to the Belgian maritime historian Basch, the earliest true lateen rig appears as early as the 1st century BC, in a Hellenistic wall painting found in a Hypogeum in Alexandria. The earliest archaeologically excavated lateen-rigged ship, the Yassi Ada II, dates to ca.400 AD, the Kelenderis ship mosaic and the Kellia ship graffito from the early 7th century complement the picture. By the 6th century, the lateen sail had largely replaced the square throughout the Mediterranean. It became the standard rig of the Byzantine dromon war galley and was also employed by Belisarius flagship in the 532 AD invasion of the Vandal kingdom. This is also indicated by the terminology of the lateen among Mediterranean Arabs and it has been suggested that the lateen sail was brought to the Indian Ocean by the Alexandrian merchants who sailed the Red Sea in Roman and later Byzantine and Arab times. Such theories have been superseded by unequivocal depictions of lateen-rigged Mediterranean sailing vessels which pre-date the Arab invasion, searches for lateen sails in India were inconclusive
4.
Prince Henry the Navigator
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Infante D. Henrique of Portugal, Duke of Viseu, better known as Prince Henry the Navigator, was an important figure in 15th-century Portuguese politics and in the early days of the Portuguese Empire. Through his administrative direction, he is regarded as the initiator of what would be known as the Age of Discoveries. King John I was the founder of the House of Aviz, Henry encouraged his father to conquer Ceuta, the Muslim port on the North African coast across the Straits of Gibraltar from the Iberian Peninsula. Henry is regarded as the patron of Portuguese exploration, Henry was the third surviving son of King John I and his wife Philippa, sister of King Henry IV of England. He was baptized in Porto, and may have been there, probably when the royal couple was living in the citys old mint, now called Casa do Infante. Another possibility is that he was born at the Monastery of Leça do Bailio, in Leça da Palmeira, Henry was 21 when he and his father and brothers captured the Moorish port of Ceuta in northern Morocco. Ceuta had long been a base for Barbary pirates who raided the Portuguese coast, following this success, Henry started to explore the coast of Africa, most of which was unknown to Europeans. His objectives included finding the source of the West African gold trade and the legendary Christian kingdom of Prester John, at that time the ships of the Mediterranean were too slow and too heavy to make these voyages. This made the caravel largely independent of the prevailing winds, with the caravel, Portuguese mariners explored the shallow waters and rivers as well as the open ocean with wide autonomy. In 1419, Henrys father appointed him governor of the province of the Algarve, in 1425, his second brother the Infante Peter, Duke of Coimbra, made a tour of Europe. While largely a diplomatic mission, among his goals was to seek out material for his brother Henry. Peter returned from Venice with a current world map drafted by a Venetian cartographer. In 1431 he donated houses for the Estudo Geral to reunite all the sciences — grammar, logic, rhetoric, arithmetic, music, for other subjects like medicine or philosophy, he ordered that each room should be decorated according to each subject that was being taught. When John I died in 1433, Henrys eldest brother Edward became king and he granted Henry all profits from trading within the areas he discovered as well as the sole right to authorize expeditions beyond Cape Bojador. Henry also held a monopoly on fishing in the Algarve. When Edward died eight years later, Henry supported his brother Peter for the regency during the minority of Edwards son Afonso V, Henry functioned as a primary organizer of the disastrous expedition to Tangier in 1437. Henrys younger brother Ferdinand was given as a hostage to guarantee that the Portuguese would fulfill the terms of the agreement that had been made with Çala Ben Çala. The Portuguese Cortes refused to approve the return of Ceuta in exchange for the Infante Ferdinand who remained in captivity until his death six years later, Prince Regent Peter had an important role and responsibility in the Portuguese maritime expansion in the Atlantic Ocean and Africa during his administration
5.
Vasco da Gama
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Vasco da Gama, 1st Count of Vidigueira, was a Portuguese explorer and the first European to reach India by sea. His initial voyage to India was the first to link Europe and Asia by a route, connecting the Atlantic and the Indian oceans and, in this way, the West. Da Gamas discovery of the sea route to India was significant and opened the way for an age of global imperialism, traveling the ocean route allowed the Portuguese to avoid sailing across the highly disputed Mediterranean and traversing the dangerous Arabian Peninsula. After decades of trying to reach the Indies, with thousands of lives and dozens of vessels lost in shipwrecks and attacks. Unopposed access to the Indian spice routes boosted the economy of the Portuguese Empire, the spices obtained from Southeast Asia were primarily pepper and cinnamon at first, but soon included other products, all new to Europe. Portugal maintained a monopoly of these commodities for several decades. Da Gama led two of the Portuguese armadas destined for India, the first and the fourth, the latter was the largest and departed for India four years after his return from the first one. For his contributions, Da Gama was appointed the Governor of India in 1524, under the title of Viceroy, Vasco da Gama remains a leading figure in the history of exploration. Numerous homages have been made worldwide to celebrate his explorations and accomplishments, the Portuguese national epic, Os Lusíadas, was written in his honour. His first trip to India is widely considered a milestone in world history, in March 2016, researchers announced that thousands of artifacts and vessel remains had been recovered from the ship Esmeralda, one of Da Gamas armada, found off the coast of Oman. Vasco da Gama was born in 1460 or 1469 in Sines, on the southwest coast of Portugal, Sines, one of the few seaports on the Alentejo coast, consisted of little more than a cluster of whitewashed, red-tiled cottages, occupied chiefly by fisherfolk. Vasco da Gamas father was Estêvão da Gama, who had served in the 1460s as a knight of the household of Infante Ferdinand and he rose in the ranks of the military Order of Santiago. Estêvão da Gama was appointed alcaide-mór of Sines in the 1460s, Estêvão da Gama married Isabel Sodré, a daughter of João Sodré, scion of a well-connected family of English origin. Her father and her brothers, Vicente Sodré and Brás Sodré, had links to the household of Infante Diogo, Duke of Viseu, and were prominent figures in the military Order of Christ. Vasco da Gama was the third of five sons of Estêvão da Gama and Isabel Sodré – in order of age, Paulo da Gama, João Sodré, Vasco da Gama, Pedro da Gama, Vasco also had one known sister, Teresa da Gama. Little is known of da Gamas early life, the Portuguese historian Teixeira de Aragão suggests that he studied at the inland town of Évora, which is where he may have learned mathematics and navigation. It has been claimed that he studied under Abraham Zacuto, an astrologer and astronomer, around 1480, da Gama followed his father and joined the Order of Santiago. The master of Santiago was Prince John, who ascended to the throne in 1481 as King John II of Portugal, John II doted on the Order, and the da Gamas prospects rose accordingly
6.
Christopher Columbus
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Christopher Columbus was an Italian explorer, navigator, colonizer, and citizen of the Republic of Genoa. Under the auspices of the Catholic Monarchs of Spain, he completed four voyages across the Atlantic Ocean and those voyages and his efforts to establish permanent settlements on the island of Hispaniola initiated the European colonization of the New World. Western imperialism and economic competition were emerging among European kingdoms through the establishment of routes and colonies. During his first voyage in 1492, he reached the New World instead of arriving at Japan as he had intended, landing on an island in the Bahamas archipelago that he named San Salvador. Over the course of three voyages, he visited the Greater and Lesser Antilles, as well as the Caribbean coast of Venezuela and Central America. These voyages had, therefore, an impact in the historical development of the modern Western world. He spearheaded the transatlantic trade and has been accused by several historians of initiating the genocide of the Hispaniola natives. Columbus himself saw his accomplishments primarily in the light of spreading the Christian religion, Columbus never admitted that he had reached a continent previously unknown to Europeans, rather than the East Indies for which he had set course. He called the inhabitants of the lands that he visited indios, the name Christopher Columbus is the Anglicisation of the Latin Christophorus Columbus. His name in Italian is Cristoforo Colombo and, in Spanish and he was born before 31 October 1451 in the territory of the Republic of Genoa, though the exact location remains disputed. His father was Domenico Colombo, a wool weaver who worked both in Genoa and Savona and who also owned a cheese stand at which young Christopher worked as a helper. Bartolomeo, Giovanni Pellegrino, and Giacomo were his brothers, Bartolomeo worked in a cartography workshop in Lisbon for at least part of his adulthood. He also had a sister named Bianchinetta, Columbus never wrote in his native language, which is presumed to have been a Genoese variety of Ligurian. In one of his writings, he says he went to sea at the age of 10, in 1470, the Columbus family moved to Savona, where Domenico took over a tavern. In the same year, Christopher was on a Genoese ship hired in the service of René of Anjou to support his attempt to conquer the Kingdom of Naples. Some modern historians have argued that he was not from Genoa but, instead and these competing hypotheses have generally been discounted by mainstream scholars. In 1473, Columbus began his apprenticeship as business agent for the important Centurione, Di Negro, later, he allegedly made a trip to Chios, an Aegean island then ruled by Genoa. In May 1476, he took part in a convoy sent by Genoa to carry valuable cargo to northern Europe
7.
Lagos, Portugal
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Lagos is a municipality at the mouth of Bensafrim River and along the Atlantic Ocean, in the Barlavento region of the Algarve, in southern Portugal. The population in 2011 was 31,049, in an area of 212.99 km², the main town of Lagos has a population of approximately 22,000. Typically, these numbers increase during the months, with the influx of visiting tourists. Yet, Lagos is also a centre of the Portuguese Age of Discovery, frequent home of Henry the Navigator, historical shipyard and, at one time. In 2012, travel website TripAdvisor, classified Lagos as the number 1 travel destination, on a list of 15 destinations on the rise worldwide, Lagos is an ancient maritime town with more than 2000 years of history. The name Lagos comes from a Celtic settlement, derived from the Latin Lacobriga and it became an early settlement of the Carthaginians, who recruited Celtic tribesmen in their war against the Romans. Owing to its important harbour, it was colonized by the Romans and integrated into the Roman province of Lusitania. Quintus Sertorius, a rebellious Roman general, helped by the Lusitanians of Lacobriga, with the fall of Rome, the town of Lagos was occupied in the 6th century by the Visigoths from the Kingdom of Toledo and later by the Byzantines. The Moors arrived in the 8th century from North Africa, renaming the settlement Zawaia and it became part of the much larger coastal region of al-Gharb, which eventually became known as the algarve. The Moors fortified the town with Lagos Castle and established important trade links to Northern Africa from their bases in the Iberian peninsula. In 1174, the local Wāli gave permission for the Christian peoples to construct a dedicated to São João Baptista. Even as King Afonso Henriques advanced to the south, the Christian Reconquista never made it into Algarve and Alentejo, King Sancho I, with the support of Crusader forces used Lagos as a stepping stone to attack the fortress of Alvôr. Zawaia was eventually captured by King Afonso III of Portugal in 1241, from this period on the King began self-styling himself as the King of Portugal and the Algarve, stressing the fact that the Algarve had been annexed into the dominion of the Portuguese. Lagos became an independent jurisdiction under the rule of King Peter I in 1361, King John I assembled his fleet in the harbour of Lagos, before setting sail for the siege and conquest of the city of Ceuta in 1415. This was the first step in opening the Muslim world to medieval Europe, by the 15th century, Lagos became the centre of Portuguese maritime exploration, with ships ordered south to trace the shoreline of Africa in order to find routes to India. Infante Henry the Navigator, third son of King John, lived most of the time in Lagos, from here he directed expeditions to Morocco and to the western coast of Africa with caravels, lateen-rigged ships with excellent seafaring capabilities. The act of rounding the Cape, much like the later rounding of the Cape of Good Hope, when, by 1443, Lançarote had sailed as far as Arguim and brought back 275 Africans, the Portuguese had sufficient slaves to relieve the perpetual handicap of agricultural labour. Over the following decades, news of discoveries and achievements, and ships loaded with spices and it was also the gateway for the first African slaves into post-medieval Europe
8.
Mediterranean Sea
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The sea is sometimes considered a part of the Atlantic Ocean, although it is usually identified as a separate body of water. The name Mediterranean is derived from the Latin mediterraneus, meaning inland or in the middle of land and it covers an approximate area of 2.5 million km2, but its connection to the Atlantic is only 14 km wide. The Strait of Gibraltar is a strait that connects the Atlantic Ocean to the Mediterranean Sea and separates Gibraltar. In oceanography, it is called the Eurafrican Mediterranean Sea or the European Mediterranean Sea to distinguish it from mediterranean seas elsewhere. The Mediterranean Sea has a depth of 1,500 m. The sea is bordered on the north by Europe, the east by Asia and it is located between latitudes 30° and 46° N and longitudes 6° W and 36° E. Its west-east length, from the Strait of Gibraltar to the Gulf of Iskenderun, the seas average north-south length, from Croatia’s southern shore to Libya, is approximately 800 km. The Mediterranean Sea, including the Sea of Marmara, has an area of approximately 2,510,000 square km. The sea was an important route for merchants and travelers of ancient times that allowed for trade, the history of the Mediterranean region is crucial to understanding the origins and development of many modern societies. In addition, the Gaza Strip and the British Overseas Territories of Gibraltar and Akrotiri, the term Mediterranean derives from the Latin word mediterraneus, meaning amid the earth or between land, as it is between the continents of Africa, Asia and Europe. The Ancient Greek name Mesogeios, is similarly from μέσο, between + γη, land, earth) and it can be compared with the Ancient Greek name Mesopotamia, meaning between rivers. The Mediterranean Sea has historically had several names, for example, the Carthaginians called it the Syrian Sea and latter Romans commonly called it Mare Nostrum, and occasionally Mare Internum. Another name was the Sea of the Philistines, from the people inhabiting a large portion of its shores near the Israelites, the sea is also called the Great Sea in the General Prologue by Geoffrey Chaucer. In Ottoman Turkish, it has also been called Bahr-i Sefid, in Modern Hebrew, it has been called HaYam HaTikhon, the Middle Sea, reflecting the Seas name in ancient Greek, Latin, and modern languages in both Europe and the Middle East. Similarly, in Modern Arabic, it is known as al-Baḥr al-Mutawassiṭ, in Turkish, it is known as Akdeniz, the White Sea since among Turks the white colour represents the west. Several ancient civilisations were located around the Mediterranean shores, and were influenced by their proximity to the sea. It provided routes for trade, colonisation, and war, as well as food for numerous communities throughout the ages, due to the shared climate, geology, and access to the sea, cultures centered on the Mediterranean tended to have some extent of intertwined culture and history. Two of the most notable Mediterranean civilisations in classical antiquity were the Greek city states, later, when Augustus founded the Roman Empire, the Romans referred to the Mediterranean as Mare Nostrum
9.
Sail
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A sail derives power from the wind to provide motive power for sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and sail-powered land vehicles. Sails mobilize lift and drag properties as air passes along the surface, in most cases sails are supported directly by a mast rigidly attached to the sailing craft or on a wire stay attached to the mast, however some craft employ a flexible mount for a mast. Sails also employ spars and battens to help determine their shape, as a result, sails come in a variety of shapes that include both triangular and quadrilateral configurations, usually with curved edges that promote three-dimensional curvature of the sail. Kites also power certain sailing craft, but do not employ a mast to support the airfoil and are beyond the scope of this article, sailing craft employ two types of rig, the square rig and the fore-and-aft rig. The square rig carries the primary driving sails are carried on horizontal spars and these spars are called yards and their tips, beyond the last stay, are called the yardarms. A ship mainly so rigged is called a square-rigger, the square rig is aerodynamically most efficient when running. A fore-and-aft rig consists of sails that are set along the line of the rather than perpendicular to it. Vessels so rigged are described as fore-and-aft rigged, archaeological studies of the Cucuteni-Trypillian culture ceramics show use of sailing boats from the sixth millennium onwards. Excavations of the Ubaid period in Mesopotamia provides direct evidence of sailing boats, Sails from ancient Egypt are depicted around 3200 BCE, where reed boats sailed upstream against the River Niles current. Ancient Sumerians used square rigged sailing boats at about the same time, the proto-Austronesian words for sail, lay, and other rigging parts date to about 3000 BCE when this group began their Pacific expansion. Greeks and Phoenicians began trading by ship by around 1,200 BCE, northern Europeans were resistant to adopting the fore-and-aft rig, despite having seen its use in the course of trade and during the Crusades. The lateen sail proved to have better performance for smaller vessels. Aerodynamic forces on sails depend on speed and direction and the speed. The direction that the craft is traveling with respect to the wind is called the point of sail. The speed of the craft at a point of sail contributes to the apparent wind —the wind speed. Depending on the alignment of the sail with the apparent wind, for apparent wind angles aligned with the entry point of the sail, the sail acts as an airfoil and lift is the predominant component of propulsion. For apparent wind angles behind the sail, lift diminishes and drag increases as the predominant component of propulsion, because of limitations on speed through the water, displacement sailboats generally derive power from sails generating lift on points of sail that include close-hauled through broad reach. Downwind sailing with a spinnaker Each rig is configured in a sail plan, a sail plan is a set of drawings, usually prepared by a naval architect which shows the various combinations of sail proposed for a sailing ship
10.
Wind
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Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the movement of air. Winds are commonly classified by their scale, their speed, the types of forces that cause them, the regions in which they occur. The strongest observed winds on a planet in the Solar System occur on Neptune, Winds have various aspects, an important one being its velocity, another the density of the gas involved, another its energy content or wind energy. In meteorology, winds are referred to according to their strength. Short bursts of high speed wind are termed gusts, strong winds of intermediate duration are termed squalls. Long-duration winds have various names associated with their strength, such as breeze, gale, storm. The two main causes of large-scale atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet, within the tropics, thermal low circulations over terrain and high plateaus can drive monsoon circulations. In coastal areas the sea breeze/land breeze cycle can define local winds, in areas that have variable terrain, mountain, Wind powers the voyages of sailing ships across Earths oceans. Hot air balloons use the wind to take trips, and powered flight uses it to increase lift. Areas of wind caused by various weather phenomena can lead to dangerous situations for aircraft. When winds become strong, trees and man-made structures are damaged or destroyed, Winds can shape landforms, via a variety of aeolian processes such as the formation of fertile soils, such as loess, and by erosion. Wind also affects the spread of wildfires, Winds can disperse seeds from various plants, enabling the survival and dispersal of those plant species, as well as flying insect populations. When combined with temperatures, wind has a negative impact on livestock. Wind affects animals food stores, as well as their hunting, Wind is caused by differences in the atmospheric pressure. When a difference in atmospheric pressure exists, air moves from the higher to the pressure area. On a rotating planet, air will also be deflected by the Coriolis effect, globally, the two major driving factors of large-scale wind patterns are the differential heating between the equator and the poles and the rotation of the planet. Outside the tropics and aloft from frictional effects of the surface, near the Earths surface, friction causes the wind to be slower than it would be otherwise
11.
Shoal
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Often it refers to those submerged ridges, banks, or bars that rise near enough to the surface of a body of water as to constitute a danger to navigation. Shoals are also known as sandbanks, sandbars, or gravelbars, two or more shoals that are either separated by shared troughs or interconnected by past and or present sedimentary and hydrographic processes are referred to as a shoal complex. The term shoal is also used in a number of ways that can be similar or quite different from how it is used in the geologic, geomorphic. Shoals are characteristically long and narrow ridges and they can develop where a stream, river, or ocean current promotes deposition of sediment and granular material, resulting in localized shallowing of the water. Marine shoals also develop either by the in place drowning of barrier islands as the result of sea level rise or by the erosion. Shoals can appear as a coastal landform in the sea, where they are classified as a type of bank, or as fluvial landforms in rivers, streams. A shoal–sandbar may seasonally separate a smaller body of water from the sea, such as, Marine lagoons Brackish water estuaries Freshwater seasonal stream and river mouths and deltas. They are typically composed of sand, although they could be of any matter that the moving water has access to and is capable of shifting around. Wave shoaling is the process when surface waves move towards shallow water, such as a beach, they slow down, their wave height increases and this behavior is called shoaling, and the waves are said to shoal. The waves may or may not build to the point where they break, depending on how large they were to begin with, in particular, waves shoal as they pass over submerged sandbanks or reefs. This can be treacherous for boats and ships, shoaling can also diffract waves, so the waves change direction. For example, if waves pass over a bank which is shallower at one end than the other. Thus the wave fronts will refract, changing direction like light passing through a prism, refraction also occurs as waves move towards a beach if the waves come in at an angle to the beach, or if the beach slopes more gradually at one end than the other. Sandbars, also known as a trough bars, form where the waves are breaking, sometimes this occurs seaward of a trough. Sand carried by the moving bottom current is deposited where the current reaches the wave break. Other longshore bars may lie further offshore, representing the point of even larger waves. A harbor or river bar is a sedimentary deposit formed at an entrance or river mouth by. Where beaches are suitably mobile, or the river’s suspended and/or bed loads are large enough, deposition can build up a sandbar that completely blocks a river mouth and damming the river
12.
Ocean current
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Depth contours, shoreline configurations, and interactions with other currents influence a currents direction and strength. Therefore ocean currents are primarily horizontal water movements, Ocean currents flow for great distances, and together, create the global conveyor belt which plays a dominant role in determining the climate of many of the Earth’s regions. More specifically, ocean currents influence the temperature of the regions through which they travel, for example, warm currents traveling along more temperate coasts increase the temperature of the area by warming the sea breezes that blow over them. Perhaps the most striking example is the Gulf Stream, which makes northwest Europe much more temperate than any region at the same latitude. Another example is Lima, Peru where the climate is cooler than the tropical latitudes in which the area is located, in these wind driven currents, the Ekman spiral effect results in the currents flowing at an angle to the driving winds. In addition, the areas of ocean currents move somewhat with the seasons. Deep ocean basins generally have a surface current, in that the eastern equatorward-flowing branch is broad. These western boundary currents are a consequence of the rotation of the Earth, Deep ocean currents are driven by density and temperature gradients. Thermohaline circulation is known as the oceans conveyor belt. These currents, called submarine rivers, flow under the surface of the ocean and are hidden from immediate detection, where significant vertical movement of ocean currents is observed, this is known as upwelling and downwelling. Deep ocean currents are currently being researched using a fleet of robots called Argo. The South Equatorial Currents of the Atlantic and Pacific straddle the equator, though the Coriolis effect is weak near the equator, water moving in the currents on either side of the equator is deflected slightly poleward and replaced by deeper water. Thus, equatorial upwelling occurs in these westward flowing equatorial surface currents, upwelling is an important process because this water from within and below the pycnocline is often rich in nutrients and greatly benefits the growth of marine organisms. By contrast, generally poor conditions for growth prevail in most of the tropical ocean because strong layering isolates deep. Ocean currents are measured in sverdrup, where 1 sv is equivalent to a flow rate of 1,000,000 m3 per second. Surface currents are found on the surface of an ocean, and are driven by large scale wind currents and they are directly affected by the wind—the Coriolis effect plays a role in their behaviors. Horizontal and vertical currents also exist below the pycnocline in the deeper waters. The movement of water due to differences in density as a function of water temperature, ripple marks in sediments, scour lines, and the erosion of rocky outcrops on deep-ocean floors are evidence that relatively strong, localized bottom currents exist
