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121-417: Mean sea level ( MSL , often shortened to sea level ) is an average surface level of one or more among Earth 's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datum  – a standardised geodetic datum  – that is used, for example, as a chart datum in cartography and marine navigation , or, in aviation, as

242-425: A color wheel —there is no mean to the set of all colors. In these situations, you must decide which mean is most useful. You can do this by adjusting the values before averaging, or by using a specialized approach for the mean of circular quantities . The Fréchet mean gives a manner for determining the "center" of a mass distribution on a surface or, more generally, Riemannian manifold . Unlike many other means,

363-574: A communist-led revolution in Afghanistan, Soviet forces invaded the country, ultimately starting the Soviet–Afghan War . In May 1988, the Soviets started to withdraw from Afghanistan , due to international opposition, persistent anti-Soviet guerrilla warfare, and a lack of support by Soviet citizens. From 1985 onwards, the last Soviet leader Mikhail Gorbachev , who sought to enact liberal reforms in

484-489: A datum . For example, hourly measurements may be averaged over a full Metonic 19-year lunar cycle to determine the mean sea level at an official tide gauge . Still-water level or still-water sea level (SWL) is the level of the sea with motions such as wind waves averaged out. Then MSL implies the SWL further averaged over a period of time such that changes due to, e.g., the tides , also have zero mean. Global MSL refers to

605-479: A random variable having that distribution. If the random variable is denoted by X {\displaystyle X} , then the mean is also known as the expected value of X {\displaystyle X} (denoted E ( X ) {\displaystyle E(X)} ). For a discrete probability distribution , the mean is given by ∑ x P ( x ) {\displaystyle \textstyle \sum xP(x)} , where

726-491: A topographic map variations in elevation are shown by contour lines . A mountain's highest point or summit is typically illustrated with the AMSL height in metres, feet or both. In unusual cases where a land location is below sea level, such as Death Valley, California , the elevation AMSL is negative. It is often necessary to compare the local height of the mean sea surface with a "level" reference surface, or geodetic datum, called

847-626: A troika was designated to take charge. Eventually Joseph Stalin , the General Secretary of the Communist Party , managed to suppress all opposition factions and consolidate power in his hands to become the country's dictator by the 1930s. Leon Trotsky , the main proponent of world revolution , was exiled from the Soviet Union in 1929, and Stalin's idea of Socialism in One Country became

968-400: A truncated mean . It involves discarding given parts of the data at the top or the bottom end, typically an equal amount at each end and then taking the arithmetic mean of the remaining data. The number of values removed is indicated as a percentage of the total number of values. The interquartile mean is a specific example of a truncated mean. It is simply the arithmetic mean after removing

1089-439: A "mean sea level" is difficult because of the many factors that affect sea level. Instantaneous sea level varies substantially on several scales of time and space. This is because the sea is in constant motion, affected by the tides, wind , atmospheric pressure, local gravitational differences, temperature, salinity , and so forth. The mean sea level at a particular location may be calculated over an extended time period and used as

1210-595: A Varangian from the Rus' people , named Rurik , was elected ruler of Novgorod in 862. In 882, his successor Oleg ventured south and conquered Kiev , which had been previously paying tribute to the Khazars . Rurik's son Igor and Igor's son Sviatoslav subsequently subdued all local East Slavic tribes to Kievan rule, destroyed the Khazar Khaganate, and launched several military expeditions to Byzantium and Persia . In

1331-501: A crisis. By 1991, economic and political turmoil began to boil over as the Baltic states chose to secede from the Soviet Union. On 17 March, a referendum was held, in which the vast majority of participating citizens voted in favour of changing the Soviet Union into a renewed federation . In June 1991, Boris Yeltsin became the first directly elected President in Russian history when he

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1452-409: A defined barometric pressure . Generally, the pressure used to set the altimeter is the barometric pressure that would exist at MSL in the region being flown over. This pressure is referred to as either QNH or "altimeter" and is transmitted to the pilot by radio from air traffic control (ATC) or an automatic terminal information service (ATIS). Since the terrain elevation is also referenced to MSL,

1573-427: A few metres, in timeframes ranging from minutes to months: Between 1901 and 2018, the average sea level rose by 15–25 cm (6–10 in), with an increase of 2.3 mm (0.091 in) per year since the 1970s. This was faster than the sea level had ever risen over at least the past 3,000 years. The rate accelerated to 4.62 mm (0.182 in)/yr for the decade 2013–2022. Climate change due to human activities

1694-417: A function f ( x ) {\displaystyle f(x)} . Intuitively, a mean of a function can be thought of as calculating the area under a section of a curve, and then dividing by the length of that section. This can be done crudely by counting squares on graph paper, or more precisely by integration . The integration formula is written as: In this case, care must be taken to make sure that

1815-639: A global superpower. After World War II, according to the Potsdam Conference , the Red Army occupied parts of Eastern and Central Europe, including East Germany and the eastern regions of Austria . Dependent communist governments were installed in the Eastern Bloc satellite states. After becoming the world's second nuclear power , the Soviet Union established the Warsaw Pact alliance, and entered into

1936-778: A large confederacy, which was subsequently taken over by the Cumans and the Kipchaks . The ancestors of Russians are among the Slavic tribes that separated from the Proto-Indo-Europeans, who appeared in the northeastern part of Europe c.  1500  years ago. The East Slavs gradually settled western Russia (approximately between modern Moscow and Saint-Petersburg ) in two waves: one moving from Kiev towards present-day Suzdal and Murom and another from Polotsk towards Novgorod and Rostov . Prior to Slavic migration, that territory

2057-430: A sample x 1 , x 2 , … , x n {\displaystyle x_{1},x_{2},\ldots ,x_{n}} , usually denoted by x ¯ {\displaystyle {\bar {x}}} , is the sum of the sampled values divided by the number of items in the sample. For example, the arithmetic mean of five values: 4, 36, 45, 50, 75 is: The geometric mean

2178-618: A secret protocol within the Molotov–Ribbentrop Pact with Nazi Germany . The Soviet Union later invaded Finland , and occupied and annexed the Baltic states , as well as parts of Romania . On 22 June 1941, Germany invaded the Soviet Union , opening the Eastern Front , the largest theater of World War II. Eventually, some 5 million Red Army troops were captured by the Nazis;

2299-460: A sharp reduction in greenhouse gas emissions, this may increase to hundreds of millions in the latter decades of the century. Local factors like tidal range or land subsidence will greatly affect the severity of impacts. For instance, sea level rise in the United States is likely to be two to three times greater than the global average by the end of the century. Yet, of the 20 countries with

2420-482: A spatial average over the entire ocean area, typically using large sets of tide gauges and/or satellite measurements. One often measures the values of MSL with respect to the land; hence a change in relative MSL or ( relative sea level ) can result from a real change in sea level, or from a change in the height of the land on which the tide gauge operates, or both. In the UK, the ordnance datum (the 0 metres height on UK maps)

2541-508: A struggle for global dominance, known as the Cold War , with the rivalling United States and NATO . After Stalin's death in 1953 and a short period of collective rule , the new leader Nikita Khrushchev denounced Stalin and launched the policy of de-Stalinization , releasing many political prisoners from the Gulag labour camps. The general easement of repressive policies became known later as

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2662-564: Is Moscow . Saint Petersburg is Russia's second-largest city and its cultural capital . The East Slavs emerged as a recognised group in Europe between the 3rd and 8th centuries CE. The first East Slavic state, Kievan Rus' , arose in the 9th century, and in 988, it adopted Orthodox Christianity from the Byzantine Empire . Kievan Rus' ultimately disintegrated; the Grand Duchy of Moscow led

2783-401: Is an average that is useful for sets of positive numbers, that are interpreted according to their product (as is the case with rates of growth) and not their sum (as is the case with the arithmetic mean): For example, the geometric mean of five values: 4, 36, 45, 50, 75 is: The harmonic mean is an average which is useful for sets of numbers which are defined in relation to some unit , as in

2904-422: Is below and half is above. The mode income is the most likely income and favors the larger number of people with lower incomes. While the median and mode are often more intuitive measures for such skewed data, many skewed distributions are in fact best described by their mean, including the exponential and Poisson distributions. The mean of a probability distribution is the long-run arithmetic average value of

3025-584: Is calibrated to the Amsterdam Peil elevation, which dates back to the 1690s. Satellite altimeters have been making precise measurements of sea level since the launch of TOPEX/Poseidon in 1992. A joint mission of NASA and CNES , TOPEX/Poseidon was followed by Jason-1 in 2001 and the Ocean Surface Topography Mission on the Jason-2 satellite in 2008. Height above mean sea level ( AMSL )

3146-425: Is due to change in either the volume of water in the world's oceans or the volume of the oceanic basins . Two major mechanisms are currently causing eustatic sea level rise. First, shrinking land ice, such as mountain glaciers and polar ice sheets, is releasing water into the oceans. Second, as ocean temperatures rise, the warmer water expands. Many factors can produce short-term changes in sea level, typically within

3267-450: Is mainly caused by human-induced climate change . When temperatures rise, mountain glaciers and polar ice sheets melt, increasing the amount of water in the oceans, while the existing seawater also expands with heat. Because most of human settlement and infrastructure was built in response to a more-normalized sea level with limited expected change, populations affected by sea level rise will need to invest in climate adaptation to mitigate

3388-487: Is the probability density function . In all cases, including those in which the distribution is neither discrete nor continuous, the mean is the Lebesgue integral of the random variable with respect to its probability measure . The mean need not exist or be finite; for some probability distributions the mean is infinite ( +∞ or −∞ ), while for others the mean is undefined . The generalized mean , also known as

3509-413: Is the arithmetic average of the values; however, for skewed distributions , the mean is not necessarily the same as the middle value (median), or the most likely value (mode). For example, mean income is typically skewed upwards by a small number of people with very large incomes, so that the majority have an income lower than the mean. By contrast, the median income is the level at which half the population

3630-411: Is the elevation (on the ground) or altitude (in the air) of an object, relative to a reference datum for mean sea level (MSL). It is also used in aviation, where some heights are recorded and reported with respect to mean sea level (contrast with flight level ), and in the atmospheric sciences , and in land surveying . An alternative is to base height measurements on a reference ellipsoid approximating

3751-718: Is the main cause. Between 1993 and 2018, melting ice sheets and glaciers accounted for 44% of sea level rise , with another 42% resulting from thermal expansion of water . Sea level rise lags behind changes in the Earth 's temperature by many decades, and sea level rise will therefore continue to accelerate between now and 2050 in response to warming that has already happened. What happens after that depends on human greenhouse gas emissions . If there are very deep cuts in emissions, sea level rise would slow between 2050 and 2100. It could then reach by 2100 slightly over 30 cm (1 ft) from now and approximately 60 cm (2 ft) from

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3872-739: Is the mean sea level measured at Newlyn in Cornwall between 1915 and 1921. Before 1921, the vertical datum was MSL at the Victoria Dock, Liverpool . Since the times of the Russian Empire , in Russia and its other former parts, now independent states, the sea level is measured from the zero level of Kronstadt Sea-Gauge. In Hong Kong, "mPD" is a surveying term meaning "metres above Principal Datum" and refers to height of 0.146 m (5.7 in) above chart datum and 1.304 m (4 ft 3.3 in) below

3993-480: Is the sum of the values divided by the number of values. The arithmetic mean of a set of numbers x 1 , x 2 , ..., x n is typically denoted using an overhead bar , x ¯ {\displaystyle {\bar {x}}} . If the numbers are from observing a sample of a larger group , the arithmetic mean is termed the sample mean ( x ¯ {\displaystyle {\bar {x}}} ) to distinguish it from

4114-543: The Battle of Kursk in the summer of 1943. Another German failure was the Siege of Leningrad , in which the city was fully blockaded on land between 1941 and 1944 by German and Finnish forces, and suffered starvation and more than a million deaths, but never surrendered. Soviet forces steamrolled through Eastern and Central Europe in 1944–1945 and captured Berlin in May 1945. In August 1945,

4235-731: The Brusilov Offensive of the Imperial Russian Army almost completely destroyed the Austro-Hungarian Army . However, the already-existing public distrust of the regime was deepened by the rising costs of war, high casualties , and rumors of corruption and treason. All this formed the climate for the Russian Revolution of 1917, carried out in two major acts. In early 1917, Nicholas II was forced to abdicate ; he and his family were imprisoned and later executed during

4356-470: The Congress of Vienna , which defined the map of post-Napoleonic Europe. The officers who pursued Napoleon into Western Europe brought ideas of liberalism back to Russia, and attempted to curtail the tsar's powers during the abortive Decembrist revolt of 1825. At the end of the conservative reign of Nicholas I (1825–1855), a zenith period of Russia's power and influence in Europe, was disrupted by defeat in

4477-677: The Crimean War . Nicholas's successor Alexander II (1855–1881) enacted significant changes throughout the country, including the emancipation reform of 1861 . These reforms spurred industrialisation, and modernised the Imperial Russian Army, which liberated much of the Balkans from Ottoman rule in the aftermath of the 1877–1878 Russo-Turkish War . During most of the 19th and early 20th century, Russia and Britain colluded over Afghanistan and its neighbouring territories in Central and South Asia;

4598-521: The Eastern Front . With the onset of the Cold War , it competed with the United States for ideological dominance and international influence . The Soviet era of the 20th century saw some of the most significant Russian technological achievements , including the first human-made satellite and the first human expedition into outer space . In 1991, the Russian SFSR emerged from the dissolution of

4719-600: The Great Northern War (1700–1721), securing Russia's access to the sea and sea trade. In 1703, on the Baltic Sea, Peter founded Saint Petersburg as Russia's new capital. Throughout his rule, sweeping reforms were made , which brought significant Western European cultural influences to Russia. He was succeeded by Catherine I (1725–1727), followed by Peter II (1727–1730), and Anna . The reign of Peter I's daughter Elizabeth in 1741–1762 saw Russia's participation in

4840-672: The Khrushchev Thaw . At the same time, Cold War tensions reached its peak when the two rivals clashed over the deployment of the United States Jupiter missiles in Turkey and Soviet missiles in Cuba . In 1957, the Soviet Union launched the world's first artificial satellite , Sputnik 1 , thus starting the Space Age . Russian cosmonaut Yuri Gagarin became the first human to orbit

4961-681: The Oldowan period in the early Lower Paleolithic . About 2 million years ago, representatives of Homo erectus migrated to the Taman Peninsula in southern Russia. Flint tools, some 1.5 million years old, have been discovered in the North Caucasus . Radiocarbon dated specimens from Denisova Cave in the Altai Mountains estimate the oldest Denisovan specimen lived 195–122,700 years ago. Fossils of Denny , an archaic human hybrid that

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5082-556: The Rurik dynasty that ruled Kievan Rus' collectively. Kiev's dominance waned, to the benefit of Vladimir-Suzdal in the north-east, the Novgorod Republic in the north, and Galicia-Volhynia in the south-west. By the 12th century, Kiev lost its pre-eminence and Kievan Rus' had fragmented into different principalities. Prince Andrey Bogolyubsky sacked Kiev in 1169 and made Vladimir his base, leading to political power being shifted to

5203-786: The Russian Civil War . The monarchy was replaced by a shaky coalition of political parties that declared itself the Provisional Government , and proclaimed the Russian Republic . On 19 January [ O.S. 6 January], 1918, the Russian Constituent Assembly declared Russia a democratic federal republic (thus ratifying the Provisional Government's decision). The next day the Constituent Assembly

5324-501: The Russian Federation , is a country spanning Eastern Europe and North Asia . It is the largest country in the world by area , extending across eleven time zones and sharing land borders with fourteen countries . It is the world's ninth-most populous country and Europe's most populous country . Russia is a highly urbanised country including 16 population centres with over a million inhabitants. Its capital and largest city

5445-667: The Russian SFSR —the world's first constitutionally socialist state . Following the Russian Civil War , the Russian SFSR established the Soviet Union with three other Soviet republics , within which it was the largest and principal constituent. At the expense of millions of lives , the Soviet Union underwent rapid industrialisation in the 1930s and later played a decisive role for the Allies in World War II by leading large-scale efforts on

5566-611: The Seven Years' War (1756–1763). During the conflict, Russian troops overran East Prussia , reaching Berlin. However, upon Elizabeth's death, all these conquests were returned to the Kingdom of Prussia by pro-Prussian Peter III of Russia . Catherine II ("the Great"), who ruled in 1762–1796, presided over the Russian Age of Enlightenment . She extended Russian political control over

5687-810: The Siberian River Routes , and by the mid-17th century, there were Russian settlements in eastern Siberia, on the Chukchi Peninsula , along the Amur River , and on the coast of the Pacific Ocean. In 1648, Semyon Dezhnyov became the first European to navigate through the Bering Strait . Under Peter the Great , Russia was proclaimed an empire in 1721, and established itself as one of the European great powers. Ruling from 1682 to 1725, Peter defeated Sweden in

5808-466: The Soviet Union , by joining the Russian SFSR into a single state with the Byelorussian , Transcaucasian , and Ukrainian republics. Eventually internal border changes and annexations during World War II created a union of 15 republics ; the largest in size and population being the Russian SFSR, which dominated the union politically, culturally, and economically. Following Lenin's death in 1924,

5929-400: The arithmetic mean (AM), the geometric mean (GM), and the harmonic mean (HM). These means were studied with proportions by Pythagoreans and later generations of Greek mathematicians because of their importance in geometry and music. The arithmetic mean (or simply mean or average ) of a list of numbers, is the sum of all of the numbers divided by their count. Similarly, the mean of

6050-643: The geoid . In the absence of external forces, the local mean sea level would coincide with this geoid surface, being an equipotential surface of the Earth's gravitational field which, in itself, does not conform to a simple sphere or ellipsoid and exhibits gravity anomalies such as those measured by NASA's GRACE satellites . In reality, the geoid surface is not directly observed, even as a long-term average, due to ocean currents, air pressure variations, temperature and salinity variations, etc. The location-dependent but time-persistent separation between local mean sea level and

6171-441: The group mean (or expected value ) of the underlying distribution, denoted μ {\displaystyle \mu } or μ x {\displaystyle \mu _{x}} . Outside probability and statistics, a wide range of other notions of mean are often used in geometry and mathematical analysis ; examples are given below. In mathematics, the three classical Pythagorean means are

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6292-414: The largest stockpile of nuclear weapons and has the third-highest military expenditure . Russia is generally considered a great power and is a regional power . Internationally, Russia ranks very low in measurements of democracy , human rights and freedom of the press ; the country also has high levels of perceived corruption . As of 2024, Russia has a high-income economy which ranks eleventh in

6413-430: The standard sea level at which atmospheric pressure is measured to calibrate altitude and, consequently, aircraft flight levels . A common and relatively straightforward mean sea-level standard is instead a long-term average of tide gauge readings at a particular reference location. Sea levels can be affected by many factors and are known to have varied greatly over geological time scales . Current sea level rise

6534-649: The 10th to 11th centuries, Kievan Rus' became one of the largest and most prosperous states in Europe. The reigns of Vladimir the Great (980–1015) and his son Yaroslav the Wise (1019–1054) constitute the Golden Age of Kiev, which saw the acceptance of Orthodox Christianity from Byzantium , and the creation of the first East Slavic written legal code , the Russkaya Pravda . The age of feudalism and decentralisation had come, marked by constant in-fighting between members of

6655-574: The 11th century and frequently in 12th-century British sources, in turn derived from Russi , 'the Russians'; and the suffix -ia . In modern historiography, this state is usually denoted as Kievan Rus' after its capital city. Another Medieval Latin name for Rus' was Ruthenia . In Russian, the current name of the country, Россия ( Rossiya ), comes from the Byzantine Greek name for Rus', Ρωσία ( Rosía ). A new form of

6776-554: The 16th century, Russia expanded east of the Ural Mountains . However, the Tsardom was weakened by the long and unsuccessful Livonian War against the coalition of the Kingdom of Poland and the Grand Duchy of Lithuania (later the united Polish–Lithuanian Commonwealth ), the Kingdom of Sweden , and Denmark–Norway for access to the Baltic coast and sea trade. In 1572, an invading army of Crimean Tatars were thoroughly defeated in

6897-965: The 19th century. With high emissions it would instead accelerate further, and could rise by 1.0 m ( 3 + 1 ⁄ 3  ft) or even 1.6 m ( 5 + 1 ⁄ 3  ft) by 2100. In the long run, sea level rise would amount to 2–3 m (7–10 ft) over the next 2000 years if warming stays to its current 1.5 °C (2.7 °F) over the pre-industrial past. It would be 19–22 metres (62–72 ft) if warming peaks at 5 °C (9.0 °F). Rising seas affect every coastal and island population on Earth. This can be through flooding, higher storm surges , king tides , and tsunamis . There are many knock-on effects. They lead to loss of coastal ecosystems like mangroves . Crop yields may reduce because of increasing salt levels in irrigation water. Damage to ports disrupts sea trade. The sea level rise projected by 2050 will expose places currently inhabited by tens of millions of people to annual flooding. Without

7018-583: The Byzantine double-headed eagle his own, and eventually Russia's, coat-of-arms. Vasili III united all of Russia by annexing the last few independent Russian states in the early 16th century. In development of the Third Rome ideas, the grand duke Ivan IV ("the Terrible") was officially crowned the first tsar of Russia in 1547. The tsar promulgated a new code of laws ( Sudebnik of 1550 ), established

7139-406: The Earth, aboard the Vostok 1 crewed spacecraft on 12 April 1961 . Following the ousting of Khrushchev in 1964, another period of collective rule ensued, until Leonid Brezhnev became the leader. The era of the 1970s and the early 1980s was later designated as the Era of Stagnation . The 1965 Kosygin reform aimed for partial decentralisation of the Soviet economy . In 1979, after

7260-402: The Fréchet mean is defined on a space whose elements cannot necessarily be added together or multiplied by scalars. It is sometimes also known as the Karcher mean (named after Hermann Karcher). In geometry, there are thousands of different definitions for the center of a triangle that can all be interpreted as the mean of a triangular set of points in the plane. This is an approximation to

7381-572: The Great changed the name of the state from Tsardom of Russia ( Russian : Русское царство , romanized :  Russkoye tsarstvo ) or Tsardom of Muscovy ( Russian : Московское царство , romanized :  Moskovskoye tsarstvo ) to Russian Empire ( Rossiiskaia imperiia ). There are several words in Russian which translate to "Russians" in English. The noun and adjective русский , russkiy refers to ethnic Russians . The adjective российский , rossiiskiy denotes Russian citizens regardless of ethnicity. The same applies to

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7502-415: The Polish–Lithuanian Commonwealth and annexed most of its territories into Russia , making it the most populous country in Europe. In the south, after the successful Russo-Turkish Wars against the Ottoman Empire , Catherine advanced Russia's boundary to the Black Sea, by dissolving the Crimean Khanate , and annexing Crimea . As a result of victories over Qajar Iran through the Russo-Persian Wars , by

7623-692: The Provisional Government and gave full governing power to the soviets, leading to the creation of the world's first socialist state . The Russian Civil War broke out between the anti-communist White movement and the Bolsheviks with its Red Army . In the aftermath of signing the Treaty of Brest-Litovsk that concluded hostilities with the Central Powers of World War I ; Bolshevist Russia surrendered most of its western territories, which hosted 34% of its population, 54% of its industries, 32% of its agricultural land, and roughly 90% of its coal mines. The Allied powers launched an unsuccessful military intervention in support of anti-communist forces. In

7744-406: The Red Army invaded Manchuria and ousted the Japanese from Northeast Asia, contributing to the Allied victory over Japan. The 1941–1945 period of World War II is known in Russia as the Great Patriotic War . The Soviet Union, along with the United States, the United Kingdom and China were considered the Big Four of Allied powers in World War II, and later became the Four Policemen , which

7865-403: The Russian autocratic state. The destruction of Kievan Rus' saw the eventual rise of the Grand Duchy of Moscow , initially a part of Vladimir-Suzdal . While still under the domain of the Mongol - Tatars and with their connivance, Moscow began to assert its influence in the region in the early 14th century, gradually becoming the leading force in the "gathering of the Russian lands". When

7986-476: The Russian parliament culminated in a constitutional crisis which ended violently through military force. During the crisis, Yeltsin was backed by Western governments, and over 100 people were killed. In December, a referendum was held and approved, which introduced a new constitution, giving the president enormous powers. The 1990s were plagued by armed conflicts in the North Caucasus , both local ethnic skirmishes and separatist Islamist insurrections. From

8107-554: The Soviet Union as the Russian Federation. A new constitution was adopted, which established a federal semi-presidential system . Since the turn of the century, Russia's political system has been dominated by Vladimir Putin , under whom the country has experienced democratic backsliding and become an authoritarian dictatorship . Russia has been militarily involved in a number of conflicts in former Soviet states and other countries , including its war with Georgia in 2008 and its war with Ukraine since 2014, which has involved

8228-408: The Soviet Union led Russia into a deep and prolonged depression. During and after the disintegration of the Soviet Union, wide-ranging reforms including privatisation and market and trade liberalisation were undertaken, including radical changes along the lines of " shock therapy ". The privatisation largely shifted control of enterprises from state agencies to individuals with inside connections in

8349-523: The Soviet Union. The transitional disorganisation of the country's agriculture, combined with the harsh state policies and a drought, led to the Soviet famine of 1932–1933 ; which killed 5.7 to 8.7 million, 3.3 million of them in the Russian SFSR. The Soviet Union, ultimately, made the costly transformation from a largely agrarian economy to a major industrial powerhouse within a short span of time. The Soviet Union entered World War II on 17 September 1939 with its invasion of Poland , in accordance with

8470-406: The Soviet system, introduced the policies of glasnost (openness) and perestroika (restructuring) in an attempt to end the period of economic stagnation and to democratise the government . This, however, led to the rise of strong nationalist and separatist movements across the country. Prior to 1991, the Soviet economy was the world's second-largest, but during its final years, it went into

8591-493: The Ukrainian leader, Bohdan Khmelnytsky , offered to place Ukraine under the protection of the Russian tsar, Alexis ; whose acceptance of this offer led to another Russo-Polish War . Ultimately, Ukraine was split along the Dnieper , leaving the eastern part, ( Left-bank Ukraine and Kiev ) under Russian rule. In the east, the rapid Russian exploration and colonisation of vast Siberia continued, hunting for valuable furs and ivory. Russian explorers pushed eastward primarily along

8712-801: The Volga-Dnieper region of southern Russia and Ukraine as the urheimat of the Proto-Indo-Europeans . Early Indo-European migrations from the Pontic–Caspian steppe of Ukraine and Russia spread Yamnaya ancestry and Indo-European languages across large parts of Eurasia. Nomadic pastoralism developed in the Pontic–Caspian steppe beginning in the Chalcolithic . Remnants of these steppe civilizations were discovered in places such as Ipatovo , Sintashta , Arkaim , and Pazyryk , which bear

8833-580: The average sea level. In France, the Marégraphe in Marseilles measures continuously the sea level since 1883 and offers the longest collated data about the sea level. It is used for a part of continental Europe and the main part of Africa as the official sea level. Spain uses the reference to measure heights below or above sea level at Alicante , while the European Vertical Reference System

8954-576: The capital Moscow. In 1612, the Poles were forced to retreat by the Russian volunteer corps, led by merchant Kuzma Minin and prince Dmitry Pozharsky . The Romanov dynasty acceded to the throne in 1613 by the decision of the Zemsky Sobor, and the country started its gradual recovery from the crisis. Russia continued its territorial growth through the 17th century, which was the age of the Cossacks . In 1654,

9075-440: The case of speed (i.e., distance per unit of time): For example, the harmonic mean of the five values: 4, 36, 45, 50, 75 is If we have five pumps that can empty a tank of a certain size in respectively 4, 36, 45, 50, and 75 minutes, then the harmonic mean of 15 {\displaystyle 15} tells us that these five different pumps working together will pump at the same rate as much as five pumps that can each empty

9196-530: The control of the Golden Horde and consolidated the whole of northern Rus' under Moscow's dominion, and was the first Russian ruler to take the title "Grand Duke of all Rus'". After the fall of Constantinople in 1453, Moscow claimed succession to the legacy of the Eastern Roman Empire . Ivan III married Sophia Palaiologina , the niece of the last Byzantine emperor Constantine XI , and made

9317-446: The crucial Battle of Molodi . The death of Ivan's sons marked the end of the ancient Rurik dynasty in 1598, and in combination with the disastrous famine of 1601–1603 , led to a civil war, the rule of pretenders, and foreign intervention during the Time of Troubles in the early 17th century. The Polish–Lithuanian Commonwealth , taking advantage, occupied parts of Russia, extending into

9438-559: The earliest known traces of horses in warfare . The genetic makeup of speakers of the Uralic language family in northern Europe was shaped by migration from Siberia that began at least 3,500 years ago. In the 3rd to 4th centuries CE, the Gothic kingdom of Oium existed in southern Russia, which was later overrun by Huns . Between the 3rd and 6th centuries CE, the Bosporan Kingdom , which

9559-483: The entire Earth, which is what systems such as GPS do. In aviation, the reference ellipsoid known as WGS84 is increasingly used to define heights; however, differences up to 100 metres (328 feet) exist between this ellipsoid height and local mean sea level. Another alternative is to use a geoid -based vertical datum such as NAVD88 and the global EGM96 (part of WGS84). Details vary in different countries. When referring to geographic features such as mountains, on

9680-474: The first Europeans to reach and colonise Alaska . In 1803–1806, the first Russian circumnavigation was made. In 1820, a Russian expedition discovered the continent of Antarctica . During the Napoleonic Wars , Russia joined alliances with various European powers, and fought against France. The French invasion of Russia at the height of Napoleon's power in 1812 reached Moscow, but eventually failed as

9801-549: The first Russian feudal representative body (the Zemsky Sobor ), revamped the military, curbed the influence of the clergy, and reorganised local government. During his long reign, Ivan nearly doubled the already large Russian territory by annexing the three Tatar khanates: Kazan and Astrakhan along the Volga , and the Khanate of Sibir in southwestern Siberia. Ultimately, by the end of

9922-571: The first half of the 19th century, Russia also conquered the Caucasus . Catherine's successor, her son Paul , was unstable and focused predominantly on domestic issues . Following his short reign, Catherine's strategy was continued with Alexander I's (1801–1825) wresting of Finland from the weakened Sweden in 1809, and of Bessarabia from the Ottomans in 1812. In North America, the Russians became

10043-481: The geoid is referred to as (mean) ocean surface topography . It varies globally in a typical range of ±1 m (3 ft). Several terms are used to describe the changing relationships between sea level and dry land. The melting of glaciers at the end of ice ages results in isostatic post-glacial rebound , when land rises after the weight of ice is removed. Conversely, older volcanic islands experience relative sea level rise, due to isostatic subsidence from

10164-485: The government, which led to the rise of Russian oligarchs . Many of the newly rich moved billions in cash and assets outside of the country in an enormous capital flight . The depression of the economy led to the collapse of social services—the birth rate plummeted while the death rate skyrocketed, and millions plunged into poverty; while extreme corruption, as well as criminal gangs and organised crime rose significantly. In late 1993, tensions between Yeltsin and

10285-621: The greatest exposure to sea level rise, twelve are in Asia , including Indonesia , Bangladesh and the Philippines. The resilience and adaptive capacity of ecosystems and countries also varies, which will result in more or less pronounced impacts. The greatest impact on human populations in the near term will occur in the low-lying Caribbean and Pacific islands . Sea level rise will make many of them uninhabitable later this century. Pilots can estimate height above sea level with an altimeter set to

10406-551: The height of planetary features. Local mean sea level (LMSL) is defined as the height of the sea with respect to a land benchmark, averaged over a period of time long enough that fluctuations caused by waves and tides are smoothed out, typically a year or more. One must adjust perceived changes in LMSL to account for vertical movements of the land, which can occur at rates similar to sea level changes (millimetres per year). Some land movements occur because of isostatic adjustment to

10527-443: The integral converges. But the mean may be finite even if the function itself tends to infinity at some points. Angles , times of day, and other cyclical quantities require modular arithmetic to add and otherwise combine numbers. In all these situations, there will not be a unique mean. For example, the times an hour before and after midnight are equidistant to both midnight and noon. It is also possible that no mean exists. Consider

10648-533: The internationally unrecognised annexations of Ukrainian territory including Crimea in 2014 and four other regions in 2022 during an ongoing invasion . Russia is a permanent member of the United Nations Security Council ; a member state of the G20 , SCO , BRICS , APEC , OSCE , and WTO ; and the leading member state of post-Soviet organisations such as CIS , CSTO , and EAEU/EEU . It possesses

10769-525: The latter deliberately starved to death or otherwise killed 3.3 million Soviet POWs , and a vast number of civilians, as the " Hunger Plan " sought to fulfil Generalplan Ost . Although the Wehrmacht had considerable early success, their attack was halted in the Battle of Moscow . Subsequently, the Germans were dealt major defeats first at the Battle of Stalingrad in the winter of 1942–1943, and then in

10890-411: The lowest and the highest quarter of values. assuming the values have been ordered, so is simply a specific example of a weighted mean for a specific set of weights. In some circumstances, mathematicians may calculate a mean of an infinite (or even an uncountable ) set of values. This can happen when calculating the mean value y avg {\displaystyle y_{\text{avg}}} of

11011-422: The mean and size of sample i {\displaystyle i} respectively. In other applications, they represent a measure for the reliability of the influence upon the mean by the respective values. Sometimes, a set of numbers might contain outliers (i.e., data values which are much lower or much higher than the others). Often, outliers are erroneous data caused by artifacts . In this case, one can use

11132-415: The mean for a moderately skewed distribution. It is used in hydrocarbon exploration and is defined as: where P 10 {\textstyle P_{10}} , P 50 {\textstyle P_{50}} and P 90 {\textstyle P_{90}} are the 10th, 50th and 90th percentiles of the distribution, respectively. Russia Russia , or

11253-669: The meantime, both the Bolsheviks and White movement carried out campaigns of deportations and executions against each other, known respectively as the Red Terror and White Terror . By the end of the violent civil war, Russia's economy and infrastructure were heavily damaged, and as many as 10 million perished during the war, mostly civilians. Millions became White émigrés , and the Russian famine of 1921–1922 claimed up to five million victims. On 30 December 1922, Lenin and his aides formed

11374-481: The melting of ice sheets at the end of the last ice age . The weight of the ice sheet depresses the underlying land, and when the ice melts away the land slowly rebounds . Changes in ground-based ice volume also affect local and regional sea levels by the readjustment of the geoid and true polar wander . Atmospheric pressure , ocean currents and local ocean temperature changes can affect LMSL as well. Eustatic sea level change (global as opposed to local change)

11495-596: The more recently coined noun россиянин , rossiianyn , "Russian" in the sense of citizen of the Russian state. According to the Primary Chronicle , the word Rus' is derived from the Rus' people , who were a Swedish tribe, and where the three original members of the Rurikid dynasty came from. The Finnish word for Swedes, ruotsi , has the same origin. Later archeological studies mostly confirmed this theory. The first human settlement on Russia dates back to

11616-533: The name Rus ' , Росия ( Rosiya ), was borrowed from the Greek term and first attested in 1387. The name Rossiia appeared in Russian sources in the late 15th century, but until the end of the 17th century the country was more often referred to by its inhabitants as Rus ' , the Russian land ( Russkaia zemlia ), or the Muscovite state ( Moskovskoe gosudarstvo ), among other variations. In 1721, Peter

11737-625: The north-east. Led by Prince Alexander Nevsky , Novgorodians repelled the invading Swedes in the Battle of the Neva in 1240, as well as the Germanic crusaders in the Battle on the Ice in 1242. Kievan Rus' finally fell to the Mongol invasion of 1237–1240, which resulted in the sacking of Kiev and other cities, as well as the death of a major part of the population. The invaders, later known as Tatars , formed

11858-601: The obstinate resistance in combination with the bitterly cold Russian winter led to a disastrous defeat of invaders, in which the pan-European Grande Armée faced utter destruction. Led by Mikhail Kutuzov and Michael Andreas Barclay de Tolly , the Imperial Russian Army ousted Napoleon and drove throughout Europe in the War of the Sixth Coalition , ultimately entering Paris. Alexander I controlled Russia's delegation at

11979-643: The official line. The continued internal struggle in the Bolshevik party culminated in the Great Purge . Under Stalin's leadership, the government launched a command economy , industrialisation of the largely rural country , and collectivisation of its agriculture . During this period of rapid economic and social change, millions of people were sent to penal labour camps , including many political convicts for their suspected or real opposition to Stalin's rule; and millions were deported and exiled to remote areas of

12100-517: The parameter m , the following types of means are obtained: This can be generalized further as the generalized f -mean and again a suitable choice of an invertible f will give The weighted arithmetic mean (or weighted average) is used if one wants to combine average values from different sized samples of the same population: Where x i ¯ {\displaystyle {\bar {x_{i}}}} and w i {\displaystyle w_{i}} are

12221-459: The pilot can estimate height above ground by subtracting the terrain altitude from the altimeter reading. Aviation charts are divided into boxes and the maximum terrain altitude from MSL in each box is clearly indicated. Once above the transition altitude, the altimeter is set to the international standard atmosphere (ISA) pressure at MSL which is 1013.25 hPa or 29.92 inHg. Mean The arithmetic mean , also known as "arithmetic average",

12342-532: The poles and 6,371.001 km (3,958.756 mi) on average. This flattened spheroid , combined with local gravity anomalies , defines the geoid of the Earth, which approximates the local mean sea level for locations in the open ocean. The geoid includes a significant depression in the Indian Ocean , whose surface dips as much as 106 m (348 ft) below the global mean sea level (excluding minor effects such as tides and currents). Precise determination of

12463-511: The power mean or Hölder mean, is an abstraction of the quadratic , arithmetic, geometric, and harmonic means. It is defined for a set of n positive numbers x i by x ¯ ( m ) = ( 1 n ∑ i = 1 n x i m ) 1 m {\displaystyle {\bar {x}}(m)=\left({\frac {1}{n}}\sum _{i=1}^{n}x_{i}^{m}\right)^{\frac {1}{m}}} By choosing different values for

12584-573: The rivalry between the two major European empires came to be known as the Great Game . The late 19th century saw the rise of various socialist movements in Russia. Alexander II was assassinated in 1881 by revolutionary terrorists. The reign of his son Alexander III (1881–1894) was less liberal but more peaceful. Under last Russian emperor, Nicholas II (1894–1917), the Revolution of 1905

12705-845: The seat of the Metropolitan of the Russian Orthodox Church moved to Moscow in 1325, its influence increased. Moscow's last rival, the Novgorod Republic , prospered as the chief fur trade centre and the easternmost port of the Hanseatic League . Led by Prince Dmitry Donskoy of Moscow, the united army of Russian principalities inflicted a milestone defeat on the Mongol-Tatars in the Battle of Kulikovo in 1380. Moscow gradually absorbed its parent duchy and surrounding principalities, including formerly strong rivals such as Tver and Novgorod . Ivan III ("the Great") threw off

12826-575: The state of the Golden Horde , which ruled over Russia for the next two centuries. Only the Novgorod Republic escaped foreign occupation after it agreed to pay tribute to the Mongols. Galicia-Volhynia would later be absorbed by Lithuania and Poland , while the Novgorod Republic continued to prosper in the north. In the northeast, the Byzantine-Slavic traditions of Kievan Rus' were adapted to form

12947-467: The sum is taken over all possible values of the random variable and P ( x ) {\displaystyle P(x)} is the probability mass function . For a continuous distribution , the mean is ∫ − ∞ ∞ x f ( x ) d x {\displaystyle \textstyle \int _{-\infty }^{\infty }xf(x)\,dx} , where f ( x ) {\displaystyle f(x)}

13068-419: The tank in 15 {\displaystyle 15} minutes. AM, GM, and HM satisfy these inequalities: Equality holds if all the elements of the given sample are equal. In descriptive statistics , the mean may be confused with the median , mode or mid-range , as any of these may incorrectly be called an "average" (more formally, a measure of central tendency ). The mean of a set of observations

13189-523: The time Chechen separatists declared independence in the early 1990s, an intermittent guerrilla war was fought between the rebel groups and Russian forces. Terrorist attacks against civilians were carried out by Chechen separatists, claiming the lives of thousands of Russian civilians. After the dissolution of the Soviet Union, Russia assumed responsibility for settling the latter's external debts. In 1992, most consumer price controls were eliminated, causing extreme inflation and significantly devaluing

13310-476: The unification of Russian lands, leading to the proclamation of the Tsardom of Russia in 1547. By the early 18th century, Russia had vastly expanded through conquest, annexation, and the efforts of Russian explorers , developing into the Russian Empire , which remains the third-largest empire in history . However, with the Russian Revolution in 1917, Russia's monarchic rule was abolished and eventually replaced by

13431-411: The weight of cooling volcanos. The subsidence of land due to the withdrawal of groundwater is another isostatic cause of relative sea level rise. On planets that lack a liquid ocean, planetologists can calculate a "mean altitude" by averaging the heights of all points on the surface. This altitude, sometimes referred to as a "sea level" or zero-level elevation , serves equivalently as a reference for

13552-528: The world by nominal GDP and fourth at purchasing power parity , relying on its vast mineral and energy resources ; the world's second-largest for oil production and natural gas production . Russia is home to 32 UNESCO World Heritage Sites . According to the Oxford English Dictionary , the English name Russia first appeared in the 14th century, borrowed from Medieval Latin : Russia , used in

13673-418: The worst effects or, when populations are at extreme risk, a process of managed retreat . The term above sea level generally refers to the height above mean sea level (AMSL). The term APSL means above present sea level, comparing sea levels in the past with the level today. Earth's radius at sea level is 6,378.137 km (3,963.191 mi) at the equator. It is 6,356.752 km (3,949.903 mi) at

13794-449: Was elected President of the Russian SFSR. In August 1991, a coup d'état attempt by members of Gorbachev's government, directed against Gorbachev and aimed at preserving the Soviet Union, instead led to the end of the Communist Party of the Soviet Union. On 25 December 1991, following the dissolution of the Soviet Union , along with contemporary Russia, fourteen other post-Soviet states emerged. The economic and political collapse of

13915-613: Was a Hellenistic polity that succeeded the Greek colonies, was also overwhelmed by nomadic invasions led by warlike tribes such as the Huns and Eurasian Avars . The Khazars , who were of Turkic origin , ruled the steppes between the Caucasus in the south, to the east past the Volga river basin, and west as far as Kyiv on the Dnieper river until the 10th century. After them came the Pechenegs who created

14036-639: Was dissolved by the All-Russian Central Executive Committee . An alternative socialist establishment co-existed, the Petrograd Soviet , wielding power through the democratically elected councils of workers and peasants, called soviets . The rule of the new authorities only aggravated the crisis in the country instead of resolving it, and eventually, the October Revolution , led by Bolshevik leader Vladimir Lenin , overthrew

14157-507: Was found at Kostyonki–Borshchyovo , and at Sungir , dating back to 34,600 years ago—both in western Russia . Humans reached Arctic Russia at least 40,000 years ago, in Mamontovaya Kurya . Ancient North Eurasian populations from Siberia genetically similar to Mal'ta–Buret' culture and Afontova Gora were an important genetic contributor to Ancient Native Americans and Eastern Hunter-Gatherers . The Kurgan hypothesis places

14278-568: Was half Neanderthal and half Denisovan, and lived some 90,000 years ago, was also found within the latter cave. Russia was home to some of the last surviving Neanderthals, from about 45,000 years ago, found in Mezmaiskaya cave . The first trace of an early modern human in Russia dates back to 45,000 years, in Western Siberia . The discovery of high concentration cultural remains of anatomically modern humans , from at least 40,000 years ago,

14399-567: Was populated by Finno-Ugrian peoples. From the 7th century onwards, the incoming East Slavs slowly assimilated the native Finno-Ugrians. The establishment of the first East Slavic states in the 9th century coincided with the arrival of Varangians , the Vikings who ventured along the waterways extending from the eastern Baltic to the Black and Caspian Seas. According to the Primary Chronicle ,

14520-522: Was the foundation of the United Nations Security Council . During the war, Soviet civilian and military death were about 26–27 million , accounting for about half of all World War II casualties . The Soviet economy and infrastructure suffered massive devastation, which caused the Soviet famine of 1946–1947 . However, at the expense of a large sacrifice, the Soviet Union emerged as

14641-681: Was triggered by the humiliating failure of the Russo-Japanese War . The uprising was put down, but the government was forced to concede major reforms ( Russian Constitution of 1906 ), including granting freedoms of speech and assembly , the legalisation of political parties, and the creation of an elected legislative body, the State Duma . In 1914, Russia entered World War I in response to Austria-Hungary 's declaration of war on Russia's ally Serbia , and fought across multiple fronts while isolated from its Triple Entente allies. In 1916,

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