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111-848: As of 2014 Matienzo is one of 13 research bases in Antarctica operated by Argentina. From 1961 to 1985 it served as a permanent base; since then it is open during the summer season only. Matienzo was founded as Lieutenant Matienzo Joint Base ( Spanish : Base Conjunta Teniente Matienzo ) on 15 March 1961 as a joint effort between the Argentine Army and the Argentine Air Force . Under the command of then Captain Ignacio Carro , several aircraft and tracked vehicles were employed to transport more than 240 t (240 long tons; 260 short tons) of cargo from Esperanza . At

222-746: A paramedic . Periodically a Twin Otter aircraft deals with the transfer of personnel and cargo, as well as waste evacuation. The base actively manages preservation and restoration of the surrounding environment; garbage and waste is removed, concentrated, classified, packaged and compacted for later disposal in the Argentine mainland. Scientists at Matienzo carry out meteorological, ionospheric , oceanographic and snow science observations; they perform aerial photographic surveys and studies on geology and geophysics involving high precision gravity and magnetism measurements. Scientific and technical staff of

333-675: A spark-gap transmitter to produce a signal with a frequency of approximately 500  kHz and a power of 100 times more than any radio signal previously produced. The message received was three dits, the Morse code for the letter S . To reach Newfoundland the signal would have to bounce off the ionosphere twice. Dr. Jack Belrose has contested this, however, based on theoretical and experimental work. However, Marconi did achieve transatlantic wireless communications in Glace Bay, Nova Scotia , one year later. In 1902, Oliver Heaviside proposed

444-631: A Spanish-based creole language called Chavacano developed in the southern Philippines. However, it is not mutually intelligible with Spanish. The number of Chavacano-speakers was estimated at 1.2 million in 1996. The local languages of the Philippines also retain significant Spanish influence, with many words derived from Mexican Spanish , owing to the administration of the islands by Spain through New Spain until 1821, until direct governance from Madrid afterwards to 1898. Ionosphere The ionosphere ( / aɪ ˈ ɒ n ə ˌ s f ɪər / )

555-411: A bit to absorption on frequencies above. However, during intense sporadic E events, the E s layer can reflect frequencies up to 50 MHz and higher. The vertical structure of the E layer is primarily determined by the competing effects of ionization and recombination. At night the E layer weakens because the primary source of ionization is no longer present. After sunset an increase in the height of

666-603: A considerable number of words from Arabic , as well as a minor influence from the Germanic Gothic language through the period of Visigoth rule in Iberia. In addition, many more words were borrowed from Latin through the influence of written language and the liturgical language of the Church. The loanwords were taken from both Classical Latin and Renaissance Latin , the form of Latin in use at that time. According to

777-522: A dramatic change in the pronunciation of its sibilant consonants , known in Spanish as the reajuste de las sibilantes , which resulted in the distinctive velar [x] pronunciation of the letter ⟨j⟩ and—in a large part of Spain—the characteristic interdental [θ] ("th-sound") for the letter ⟨z⟩ (and for ⟨c⟩ before ⟨e⟩ or ⟨i⟩ ). See History of Spanish (Modern development of

888-482: A first language by Spaniards and educated Filipinos ( Ilustrados ). Despite a public education system set up by the colonial government, by the end of Spanish rule in 1898, only about 10% of the population had knowledge of Spanish, mostly those of Spanish descent or elite standing. Spanish continued to be official and used in Philippine literature and press during the early years of American administration after

999-706: A geomagnetic storm the F₂ layer will become unstable, fragment, and may even disappear completely. In the Northern and Southern polar regions of the Earth aurorae will be observable in the night sky. Lightning can cause ionospheric perturbations in the D-region in one of two ways. The first is through VLF (very low frequency) radio waves launched into the magnetosphere . These so-called "whistler" mode waves can interact with radiation belt particles and cause them to precipitate onto

1110-487: A high frequency (3–30 MHz) radio blackout that can persist for many hours after strong flares. During this time very low frequency (3–30 kHz) signals will be reflected by the D layer instead of the E layer, where the increased atmospheric density will usually increase the absorption of the wave and thus dampen it. As soon as the X-rays end, the sudden ionospheric disturbance (SID) or radio black-out steadily declines as

1221-478: A long history in the territory of the current-day United States dating back to the 16th century. In the wake of the 1848 Guadalupe Hidalgo Treaty , hundreds of thousands of Spanish speakers became a minoritized community in the United States. The 20th century saw further massive growth of Spanish speakers in areas where they had been hitherto scarce. According to the 2020 census, over 60 million people of

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1332-508: A primarily Hassaniya Arabic -speaking territory, Spanish was officially spoken as the language of the colonial administration during the late 19th and 20th centuries. Today, Spanish is present in the partially-recognized Sahrawi Arab Democratic Republic as its secondary official language, and in the Sahrawi refugee camps in Tindouf ( Algeria ), where the Spanish language is still taught as

1443-417: A radio wave reaches the ionosphere, the electric field in the wave forces the electrons in the ionosphere into oscillation at the same frequency as the radio wave. Some of the radio-frequency energy is given up to this resonant oscillation. The oscillating electrons will then either be lost to recombination or will re-radiate the original wave energy. Total refraction can occur when the collision frequency of

1554-479: A result of lightning activity. Their subsequent research has focused on the mechanism by which this process can occur. Due to the ability of ionized atmospheric gases to refract high frequency (HF, or shortwave ) radio waves, the ionosphere can reflect radio waves directed into the sky back toward the Earth. Radio waves directed at an angle into the sky can return to Earth beyond the horizon. This technique, called "skip" or " skywave " propagation, has been used since

1665-617: A second language features characteristics involving the variability of the vowel system. While far from its heyday during the Spanish protectorate in Morocco , the Spanish language has some presence in northern Morocco , stemming for example from the availability of certain Spanish-language media. According to a 2012 survey by Morocco's Royal Institute for Strategic Studies (IRES), penetration of Spanish in Morocco reaches 4.6% of

1776-531: A second language, largely by Cuban educators. The number of Spanish speakers is unknown. Spanish is also an official language of the African Union . Spanish was an official language of the Philippines from the beginning of Spanish administration in 1565 to a constitutional change in 1973. During Spanish colonization , it was the language of government, trade, and education, and was spoken as

1887-447: A warehouse and several deposits. The 1,500 m (4,900 ft) long airstrip is located over a nearby glacier 2 km (1.2 mi) away, and is usable by all kind of ski-mounting aircraft. The snow-covered helipad is 1,500 m (4,900 ft) south from the base; several Bell 212 helicopters are used for deployment and supply of scientific personnel. Matienzo also has a basic 15 m (160 sq ft) infirmary attended by

1998-416: Is cognate to the root word of satisfacer ("to satisfy"), and hecho ("made") is similarly cognate to the root word of satisfecho ("satisfied"). Compare the examples in the following table: Some consonant clusters of Latin also produced characteristically different results in these languages, as shown in the examples in the following table: In the 15th and 16th centuries, Spanish underwent

2109-666: Is a Romance language of the Indo-European language family that evolved from the Vulgar Latin spoken on the Iberian Peninsula of Europe . Today, it is a global language with about 500 million native speakers, mainly in the Americas and Spain , and about 600 million when including second language speakers. Spanish is the official language of 20 countries , as well as one of the six official languages of

2220-404: Is actually lower in the local summer months. This effect is known as the winter anomaly. The anomaly is always present in the northern hemisphere, but is usually absent in the southern hemisphere during periods of low solar activity. Within approximately ± 20 degrees of the magnetic equator , is the equatorial anomaly. It is the occurrence of a trough in the ionization in the F 2 layer at

2331-460: Is also common, sometimes to distances of 15,000 km (9,300 mi) or more. The F layer or region, also known as the Appleton–Barnett layer, extends from about 150 km (93 mi) to more than 500 km (310 mi) above the surface of Earth. It is the layer with the highest electron density, which implies signals penetrating this layer will escape into space. Electron production

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2442-677: Is currently used to compensate for ionospheric effects in GPS . This model was developed at the US Air Force Geophysical Research Laboratory circa 1974 by John (Jack) Klobuchar . The Galileo navigation system uses the NeQuick model . GALILEO broadcasts 3 coefficients to compute the effective ionization level, which is then used by the NeQuick model to compute a range delay along the line-of-sight. The open system electrodynamic tether , which uses

2553-448: Is dominated by extreme ultraviolet (UV, 10–100 nm) radiation ionizing atomic oxygen. The F layer consists of one layer (F 2 ) at night, but during the day, a secondary peak (labelled F 1 ) often forms in the electron density profile. Because the F 2 layer remains by day and night, it is responsible for most skywave propagation of radio waves and long distance high frequency (HF, or shortwave ) radio communications. Above

2664-508: Is enough to absorb most (if not all) transpolar HF radio signal transmissions. Such events typically last less than 24 to 48 hours. The E layer is the middle layer, 90 to 150 km (56 to 93 mi) above the surface of the Earth. Ionization is due to soft X-ray (1–10 nm) and far ultraviolet (UV) solar radiation ionization of molecular oxygen (O 2 ). Normally, at oblique incidence, this layer can only reflect radio waves having frequencies lower than about 10 MHz and may contribute

2775-454: Is estimated that about 486 million people speak Spanish as a native language , making it the second most spoken language by number of native speakers . An additional 75 million speak Spanish as a second or foreign language , making it the fourth most spoken language in the world overall after English, Mandarin Chinese, and Hindi with a total number of 538 million speakers. Spanish is also

2886-761: Is heavily influenced by Venezuelan Spanish. In addition to sharing most of its borders with Spanish-speaking countries, the creation of Mercosur in the early 1990s induced a favorable situation for the promotion of Spanish language teaching in Brazil . In 2005, the National Congress of Brazil approved a bill, signed into law by the President , making it mandatory for schools to offer Spanish as an alternative foreign language course in both public and private secondary schools in Brazil. In September 2016 this law

2997-537: Is higher than the plasma frequency of the ionosphere, then the electrons cannot respond fast enough, and they are not able to re-radiate the signal. It is calculated as shown below: where N = electron density per m and f critical is in Hz. The Maximum Usable Frequency (MUF) is defined as the upper frequency limit that can be used for transmission between two points at a specified time. where α {\displaystyle \alpha } = angle of arrival ,

3108-732: Is related to Castile ( Castilla or archaically Castiella ), the kingdom where the language was originally spoken. The name Castile , in turn, is usually assumed to be derived from castillo ('castle'). In the Middle Ages , the language spoken in Castile was generically referred to as Romance and later also as Lengua vulgar . Later in the period, it gained geographical specification as Romance castellano ( romanz castellano , romanz de Castiella ), lenguaje de Castiella , and ultimately simply as castellano (noun). Different etymologies have been suggested for

3219-844: Is spoken by very small communities in Angola due to Cuban influence from the Cold War and in South Sudan among South Sudanese natives that relocated to Cuba during the Sudanese wars and returned for their country's independence. Spanish is also spoken in the integral territories of Spain in Africa, namely the cities of Ceuta and Melilla and the Canary Islands , located in the Atlantic Ocean some 100 km (62 mi) off

3330-411: Is sufficient to affect radio propagation . This portion of the atmosphere is partially ionized and contains a plasma which is referred to as the ionosphere. Ultraviolet (UV), X-ray and shorter wavelengths of solar radiation are ionizing, since photons at these frequencies contain sufficient energy to dislodge an electron from a neutral gas atom or molecule upon absorption. In this process

3441-591: Is the ionized part of the upper atmosphere of Earth , from about 48 km (30 mi) to 965 km (600 mi) above sea level , a region that includes the thermosphere and parts of the mesosphere and exosphere . The ionosphere is ionized by solar radiation . It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere . It has practical importance because, among other functions, it influences radio propagation to distant places on Earth . It also affects GPS signals that travel through this layer. As early as 1839,

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3552-813: Is the de facto national language of the country, Spanish is often used in public services and notices at the federal and state levels. Spanish is also used in administration in the state of New Mexico . The language has a strong influence in major metropolitan areas such as those of Los Angeles , Miami , San Antonio , New York , San Francisco , Dallas , Tucson and Phoenix of the Arizona Sun Corridor , as well as more recently, Chicago , Las Vegas , Boston , Denver , Houston , Indianapolis , Philadelphia , Cleveland , Salt Lake City , Atlanta , Nashville , Orlando , Tampa , Raleigh and Baltimore-Washington, D.C. due to 20th- and 21st-century immigration. Although Spanish has no official recognition in

3663-405: Is the main reason for absorption of HF radio waves , particularly at 10 MHz and below, with progressively less absorption at higher frequencies. This effect peaks around noon and is reduced at night due to a decrease in the D layer's thickness; only a small part remains due to cosmic rays . A common example of the D layer in action is the disappearance of distant AM broadcast band stations in

3774-502: Is useful in crossing international boundaries and covering large areas at low cost. Automated services still use shortwave radio frequencies, as do radio amateur hobbyists for private recreational contacts and to assist with emergency communications during natural disasters. Armed forces use shortwave so as to be independent of vulnerable infrastructure, including satellites, and the low latency of shortwave communications make it attractive to stock traders, where milliseconds count. When

3885-729: The Argentine Antarctic Institute uses part of its facilities for winter–spring activities. The base is the launching point for expeditions to the Larsen Ice Shelf and Jason Peninsula . Staff of the National Meteorological Service commissioned at Matienzo keeps track of the masses of ice, solar radiation and atmospheric parameters. Retreat and collapse of the Larsen Ice Shelf is constantly monitored by analyzing satellite imagery, GPS positioning and terrain data to investigate

3996-601: The Committee on Space Research (COSPAR) and the International Union of Radio Science (URSI). The major data sources are the worldwide network of ionosondes , the powerful incoherent scatter radars (Jicamarca, Arecibo , Millstone Hill, Malvern, St Santin), the ISIS and Alouette topside sounders , and in situ instruments on several satellites and rockets. IRI is updated yearly. IRI is more accurate in describing

4107-568: The Spanish as a First Foreign Language (SAFFL) initiative in March 2005. Spanish has historically had a significant presence on the Dutch Caribbean islands of Aruba , Bonaire and Curaçao ( ABC Islands ) throughout the centuries and in present times. The majority of the populations of each island (especially Aruba) speaking Spanish at varying although often high degrees of fluency. The local language Papiamentu (Papiamento on Aruba)

4218-508: The Spanish–American War but was eventually replaced by English as the primary language of administration and education by the 1920s. Nevertheless, despite a significant decrease in influence and speakers, Spanish remained an official language of the Philippines upon independence in 1946, alongside English and Filipino , a standardized version of Tagalog . Spanish was briefly removed from official status in 1973 but reimplemented under

4329-548: The United Nations . Spanish is the world's second-most spoken native language after Mandarin Chinese ; the world's fourth-most spoken language overall after English , Mandarin Chinese, and Hindustani ( Hindi - Urdu ); and the world's most widely spoken Romance language. The country with the largest population of native speakers is Mexico . Spanish is part of the Ibero-Romance language group , in which

4440-674: The University of Tucumán and the Instituto de Investigaciones Aeronáuticas y Espaciales . That year the base name was changed to the present one. On 29 July 1968 a Beaver P-05 took off from Matienzo with the mission of assisting a critically ill medical patient in the British Base "F" on the Argentine Islands . Amidst very bad weather, the aircraft crashed without casualties and the evacuation had to be delayed until

4551-577: The icebreaker ARA General San Martín could finally take over and succeed with the mission. Matienzo stayed closed through the 1972–1973 campaign, and was reopened on 8 September 1974; it was closed again for the 1984–1985 campaign and reopened once again, although it has been a summer-only base ever since. As of 2008 Matienzo is composed of 6 buildings and includes facilities such as: main and emergency houses, airstrip, helipad , fuel platform, central power station with two Antarctic gas oil generators, waste treatment plant, laboratory, freezing chamber,

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4662-448: The troposphere , extends from the surface to about 10 km (6 mi). Above that is the stratosphere , followed by the mesosphere. In the stratosphere incoming solar radiation creates the ozone layer . At heights of above 80 km (50 mi), in the thermosphere , the atmosphere is so thin that free electrons can exist for short periods of time before they are captured by a nearby positive ion . The number of these free electrons

4773-480: The 13th century. Spanish colonialism in the early modern period spurred the introduction of the language to overseas locations, most notably to the Americas. As a Romance language, Spanish is a descendant of Latin. Around 75% of modern Spanish vocabulary is Latin in origin, including Latin borrowings from Ancient Greek. Alongside English and French , it is also one of the most taught foreign languages throughout

4884-399: The 1920s to communicate at international or intercontinental distances. The returning radio waves can reflect off the Earth's surface into the sky again, allowing greater ranges to be achieved with multiple hops . This communication method is variable and unreliable, with reception over a given path depending on time of day or night, the seasons, weather, and the 11-year sunspot cycle . During

4995-404: The 2021–2022 school year alone. The local business process outsourcing industry has also helped boost the language's economic prospects. Today, while the actual number of proficient Spanish speakers is around 400,000, or under 0.5% of the population, a new generation of Spanish speakers in the Philippines has likewise emerged, though speaker estimates vary widely. Aside from standard Spanish,

5106-595: The 20th century, Spanish was introduced to Equatorial Guinea and the Western Sahara , and to areas of the United States that had not been part of the Spanish Empire, such as Spanish Harlem in New York City . For details on borrowed words and other external influences upon Spanish, see Influences on the Spanish language . Spanish is the primary language in 20 countries worldwide. As of 2023, it

5217-443: The D layer, so there are many more neutral air molecules than ions. Medium frequency (MF) and lower high frequency (HF) radio waves are significantly attenuated within the D layer, as the passing radio waves cause electrons to move, which then collide with the neutral molecules, giving up their energy. Lower frequencies experience greater absorption because they move the electrons farther, leading to greater chance of collisions. This

5328-706: The E layer maximum increases the range to which radio waves can travel by reflection from the layer. This region is also known as the Kennelly–Heaviside layer or simply the Heaviside layer. Its existence was predicted in 1902 independently and almost simultaneously by the American electrical engineer Arthur Edwin Kennelly (1861–1939) and the British physicist Oliver Heaviside (1850–1925). In 1924 its existence

5439-654: The Equatoguinean education system and is the primary language used in government and business. Whereas it is not the mother tongue of virtually any of its speakers, the vast majority of the population is proficient in Spanish. The Instituto Cervantes estimates that 87.7% of the population is fluent in Spanish. The proportion of proficient Spanish speakers in Equatorial Guinea exceeds the proportion of proficient speakers in other West and Central African nations of their respective colonial languages. Spanish

5550-532: The F 1 layer. The F 2 layer persists by day and night and is the main region responsible for the refraction and reflection of radio waves. The D layer is the innermost layer, 48 to 90 km (30 to 56 mi) above the surface of the Earth. Ionization here is due to Lyman series -alpha hydrogen radiation at a wavelength of 121.6 nanometre (nm) ionizing nitric oxide (NO). In addition, solar flares can generate hard X-rays (wavelength < 1 nm ) that ionize N 2 and O 2 . Recombination rates are high in

5661-458: The F 2 layer daytime ion production is higher in the summer, as expected, since the Sun shines more directly on the Earth. However, there are seasonal changes in the molecular-to-atomic ratio of the neutral atmosphere that cause the summer ion loss rate to be even higher. The result is that the increase in the summertime loss overwhelms the increase in summertime production, and total F 2 ionization

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5772-488: The F layer, the number of oxygen ions decreases and lighter ions such as hydrogen and helium become dominant. This region above the F layer peak and below the plasmasphere is called the topside ionosphere. From 1972 to 1975 NASA launched the AEROS and AEROS B satellites to study the F region. An ionospheric model is a mathematical description of the ionosphere as a function of location, altitude, day of year, phase of

5883-682: The German mathematician and physicist Carl Friedrich Gauss postulated that an electrically conducting region of the atmosphere could account for observed variations of Earth's magnetic field. Sixty years later, Guglielmo Marconi received the first trans-Atlantic radio signal on December 12, 1901, in St. John's, Newfoundland (now in Canada ) using a 152.4 m (500 ft) kite-supported antenna for reception. The transmitting station in Poldhu , Cornwall, used

5994-705: The Iberian Peninsula. These languages included Proto-Basque , Iberian , Lusitanian , Celtiberian and Gallaecian . The first documents to show traces of what is today regarded as the precursor of modern Spanish are from the 9th century. Throughout the Middle Ages and into the modern era , the most important influences on the Spanish lexicon came from neighboring Romance languages — Mozarabic ( Andalusi Romance ), Navarro-Aragonese , Leonese , Catalan/Valencian , Portuguese , Galician , Occitan , and later, French and Italian . Spanish also borrowed

6105-689: The Matienzo–Esperanza route and the coastal channel route between the Robertson Island and the 72° 30' S position. Also, topographic and aerial photographic surveys of the Larsen Ice Shelf were made. In 1965 two Gamma Centauro sounding rockets developed by the Argentine Air Force and two high altitude balloons carrying instruments for x-ray measurements where launched from the base, under collaboration with

6216-540: The Old Spanish sibilants) for details. The Gramática de la lengua castellana , written in Salamanca in 1492 by Elio Antonio de Nebrija , was the first grammar written for a modern European language. According to a popular anecdote, when Nebrija presented it to Queen Isabella I , she asked him what was the use of such a work, and he answered that language is the instrument of empire. In his introduction to

6327-597: The Spanish-speaking world, Spanish is called not only español but also castellano (Castilian), the language from the Kingdom of Castile , contrasting it with other languages spoken in Spain such as Galician , Basque , Asturian , Catalan/Valencian , Aragonese , Occitan and other minor languages. The Spanish Constitution of 1978 uses the term castellano to define the official language of

6438-453: The Sun at any one time. Sunspot active regions are the source of increased coronal heating and accompanying increases in EUV and X-ray irradiance, particularly during episodic magnetic eruptions that include solar flares that increase ionization on the sunlit side of the Earth and solar energetic particle events that can increase ionization in the polar regions. Thus the degree of ionization in

6549-502: The U.S. population were of Hispanic or Hispanic American by origin. In turn, 41.8 million people in the United States aged five or older speak Spanish at home, or about 13% of the population. Spanish predominates in the unincorporated territory of Puerto Rico , where it is also an official language along with English. Spanish is by far the most common second language in the country, with over 50 million total speakers if non-native or second-language speakers are included. While English

6660-457: The administration of Ferdinand Marcos two months later. It remained an official language until the ratification of the present constitution in 1987, in which it was re-designated as a voluntary and optional auxiliary language. Additionally, the constitution, in its Article XIV, stipulates that the Government shall provide the people of the Philippines with a Spanish-language translation of

6771-441: The angle of the wave relative to the horizon , and sin is the sine function. The cutoff frequency is the frequency below which a radio wave fails to penetrate a layer of the ionosphere at the incidence angle required for transmission between two specified points by refraction from the layer. There are a number of models used to understand the effects of the ionosphere on global navigation satellite systems. The Klobuchar model

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6882-449: The atmosphere near the magnetic poles increasing the ionization of the D and E layers. PCA's typically last anywhere from about an hour to several days, with an average of around 24 to 36 hours. Coronal mass ejections can also release energetic protons that enhance D-region absorption in the polar regions. Geomagnetic storms and ionospheric storms are temporary and intense disturbances of the Earth's magnetosphere and ionosphere. During

6993-463: The base was transferred under exclusive command of the Air Force, and renamed as Destacamento Aeronáutico Teniente Matienzo ("Lieutenant Matienzo Aeronautical Detachment"), The Air Force kept a number of planes for exclusive service of the base. During 1964 an extensive program of meteorological and climatological observations was fulfilled: it included studying the glaciological profile across

7104-684: The classic hispanus or hispanicus took the suffix -one from Vulgar Latin , as happened with other words such as bretón (Breton) or sajón (Saxon). Like the other Romance languages , the Spanish language evolved from Vulgar Latin , which was brought to the Iberian Peninsula by the Romans during the Second Punic War , beginning in 210 BC. Several pre-Roman languages (also called Paleohispanic languages )—some distantly related to Latin as Indo-European languages , and some that are not related at all—were previously spoken in

7215-500: The consonant written b (a bilabial with plosive and fricative allophones). In modern Spanish, there is no difference between the pronunciation of orthographic b and v . Typical of Spanish (as also of neighboring Gascon extending as far north as the Gironde estuary , and found in a small area of Calabria ), attributed by some scholars to a Basque substratum was the mutation of Latin initial f into h- whenever it

7326-404: The country's constitution. In recent years changing attitudes among non-Spanish speaking Filipinos have helped spur a revival of the language, and starting in 2009 Spanish was reintroduced as part of the basic education curriculum in a number of public high schools, becoming the largest foreign language program offered by the public school system, with over 7,000 students studying the language in

7437-412: The daytime. During solar proton events , ionization can reach unusually high levels in the D-region over high and polar latitudes. Such very rare events are known as Polar Cap Absorption (or PCA) events, because the increased ionization significantly enhances the absorption of radio signals passing through the region. In fact, absorption levels can increase by many tens of dB during intense events, which

7548-483: The discovery of HF radio propagation via the ionosphere in 1923. In 1925, observations during a solar eclipse in New York by Dr. Alfred N. Goldsmith and his team demonstrated the influence of sunlight on radio wave propagation, revealing that short waves became weak or inaudible while long waves steadied during the eclipse, thus contributing to the understanding of the ionosphere's role in radio transmission. In 1926, Scottish physicist Robert Watson-Watt introduced

7659-423: The electrons in the D-region recombine rapidly and propagation gradually returns to pre-flare conditions over minutes to hours depending on the solar flare strength and frequency. Associated with solar flares is a release of high-energy protons. These particles can hit the Earth within 15 minutes to 2 hours of the solar flare. The protons spiral around and down the magnetic field lines of the Earth and penetrate into

7770-453: The end of 1962 Matienzo was the launch site for the first major Air Force operation in the Antarctic. In what was called Operación Sur ("Operation South"), a Douglas C-47 (TA-33) commanded by then Captain Mario Luis Olezza took off from the base trying to reach the South Pole and then land on McMurdo Station . This first attempt failed due to a fire in the airplane's engines. The plan could only materialize in 1965. On 15 November 1963

7881-431: The equator and crests at about 17 degrees in magnetic latitude. The Earth's magnetic field lines are horizontal at the magnetic equator. Solar heating and tidal oscillations in the lower ionosphere move plasma up and across the magnetic field lines. This sets up a sheet of electric current in the E region which, with the horizontal magnetic field, forces ionization up into the F layer, concentrating at ± 20 degrees from

7992-609: The existence of the Kennelly–Heaviside layer of the ionosphere which bears his name. Heaviside's proposal included means by which radio signals are transmitted around the Earth's curvature. Also in 1902, Arthur Edwin Kennelly discovered some of the ionosphere's radio-electrical properties. In 1912, the U.S. Congress imposed the Radio Act of 1912 on amateur radio operators , limiting their operations to frequencies above 1.5 MHz (wavelength 200 meters or smaller). The government thought those frequencies were useless. This led to

8103-415: The first half of the 20th century it was widely used for transoceanic telephone and telegraph service, and business and diplomatic communication. Due to its relative unreliability, shortwave radio communication has been mostly abandoned by the telecommunications industry, though it remains important for high-latitude communication where satellite-based radio communication is not possible. Shortwave broadcasting

8214-457: The first radio modification of the ionosphere; HAARP ran a series of experiments in 2017 using the eponymous Luxembourg Effect . Edward V. Appleton was awarded a Nobel Prize in 1947 for his confirmation in 1927 of the existence of the ionosphere. Lloyd Berkner first measured the height and density of the ionosphere. This permitted the first complete theory of short-wave radio propagation. Maurice V. Wilkes and J. A. Ratcliffe researched

8325-683: The following table: Spanish is marked by palatalization of the Latin double consonants ( geminates ) nn and ll (thus Latin annum > Spanish año , and Latin anellum > Spanish anillo ). The consonant written u or v in Latin and pronounced [w] in Classical Latin had probably " fortified " to a bilabial fricative /β/ in Vulgar Latin. In early Spanish (but not in Catalan or Portuguese) it merged with

8436-466: The former British colony of Belize (known until 1973 as British Honduras ) where English is the sole official language, according to the 2022 census, 54% of the total population are able to speak the language. Due to its proximity to Spanish-speaking countries and small existing native Spanish speaking minority, Trinidad and Tobago has implemented Spanish language teaching into its education system. The Trinidadian and Tobagonian government launched

8547-604: The grammar, dated 18 August 1492, Nebrija wrote that "... language was always the companion of empire." From the 16th century onwards, the language was taken to the Spanish-discovered America and the Spanish East Indies via Spanish colonization of America . Miguel de Cervantes , author of Don Quixote , is such a well-known reference in the world that Spanish is often called la lengua de Cervantes ("the language of Cervantes"). In

8658-444: The ice-climate interactions in critical areas under climate change conditions. The median annual temperature at the base is −11.6 °C (11.1 °F); the highest temperature ever recorded was 13.1 °C (55.6 °F) on 16 March 1965, and the lowest, −44.4 °C (−47.9 °F) on 5 August 1964. Spanish language This is an accepted version of this page Spanish ( español ) or Castilian ( castellano )

8769-508: The interactions of the ions and electrons with the neutral atmosphere and sunlight, or it may be a statistical description based on a large number of observations or a combination of physics and observations. One of the most widely used models is the International Reference Ionosphere (IRI), which is based on data and specifies the four parameters just mentioned. The IRI is an international project sponsored by

8880-465: The ionosphere and decrease the ionization. Sydney Chapman proposed that the region below the ionosphere be called neutrosphere (the neutral atmosphere ). At night the F layer is the only layer of significant ionization present, while the ionization in the E and D layers is extremely low. During the day, the D and E layers become much more heavily ionized, as does the F layer, which develops an additional, weaker region of ionisation known as

8991-421: The ionosphere follows both a diurnal (time of day) cycle and the 11-year solar cycle . There is also a seasonal dependence in ionization degree since the local winter hemisphere is tipped away from the Sun, thus there is less received solar radiation. Radiation received also varies with geographical location (polar, auroral zones, mid-latitudes , and equatorial regions). There are also mechanisms that disturb

9102-404: The ionosphere is less than the radio frequency, and if the electron density in the ionosphere is great enough. A qualitative understanding of how an electromagnetic wave propagates through the ionosphere can be obtained by recalling geometric optics . Since the ionosphere is a plasma, it can be shown that the refractive index is less than unity. Hence, the electromagnetic "ray" is bent away from

9213-444: The ionosphere, adding ionization to the D-region. These disturbances are called "lightning-induced electron precipitation " (LEP) events. Additional ionization can also occur from direct heating/ionization as a result of huge motions of charge in lightning strikes. These events are called early/fast. In 1925, C. T. R. Wilson proposed a mechanism by which electrical discharge from lightning storms could propagate upwards from clouds to

9324-474: The ionosphere. On July 26, 1963, the first operational geosynchronous satellite Syncom 2 was launched. On board radio beacons on this satellite (and its successors) enabled – for the first time – the measurement of total electron content (TEC) variation along a radio beam from geostationary orbit to an earth receiver. (The rotation of the plane of polarization directly measures TEC along the path.) Australian geophysicist Elizabeth Essex-Cohen from 1969 onwards

9435-678: The ionosphere. Around the same time, Robert Watson-Watt, working at the Radio Research Station in Slough, UK, suggested that the ionospheric sporadic E layer (E s ) appeared to be enhanced as a result of lightning but that more work was needed. In 2005, C. Davis and C. Johnson, working at the Rutherford Appleton Laboratory in Oxfordshire, UK, demonstrated that the E s layer was indeed enhanced as

9546-445: The ionosphere. At the magnetic dip equator, where the geomagnetic field is horizontal, this electric field results in an enhanced eastward current flow within ± 3 degrees of the magnetic equator, known as the equatorial electrojet . When the Sun is active, strong solar flares can occur that hit the sunlit side of Earth with hard X-rays. The X-rays penetrate to the D-region, releasing electrons that rapidly increase absorption, causing

9657-540: The language is also known as Castilian ( castellano ). The group evolved from several dialects of Vulgar Latin in Iberia after the collapse of the Western Roman Empire in the 5th century. The oldest Latin texts with traces of Spanish come from mid-northern Iberia in the 9th century, and the first systematic written use of the language happened in Toledo , a prominent city of the Kingdom of Castile , in

9768-549: The language's hegemony in an intensely centralising Spanish state were established from the 18th century onward. Other European territories in which it is also widely spoken include Gibraltar and Andorra . Spanish is also spoken by immigrant communities in other European countries, such as the United Kingdom , France , Italy , and Germany . Spanish is an official language of the European Union . Today,

9879-462: The light electron obtains a high velocity so that the temperature of the created electronic gas is much higher (of the order of thousand K) than the one of ions and neutrals. The reverse process to ionization is recombination , in which a free electron is "captured" by a positive ion. Recombination occurs spontaneously, and causes the emission of a photon carrying away the energy produced upon recombination. As gas density increases at lower altitudes,

9990-400: The magnetic equator. This phenomenon is known as the equatorial fountain . The worldwide solar-driven wind results in the so-called Sq (solar quiet) current system in the E region of the Earth's ionosphere ( ionospheric dynamo region ) (100–130 km (60–80 mi) altitude). Resulting from this current is an electrostatic field directed west–east (dawn–dusk) in the equatorial day side of

10101-694: The majority of the Spanish speakers live in Hispanic America . Nationally, Spanish is the official language—either de facto or de jure —of Argentina , Bolivia (co-official with 36 indigenous languages), Chile , Colombia , Costa Rica , Cuba , Dominican Republic , Ecuador , El Salvador , Guatemala , Honduras , Mexico (co-official with 63 indigenous languages), Nicaragua , Panama , Paraguay (co-official with Guaraní ), Peru (co-official with Quechua , Aymara , and "the other indigenous languages"), Puerto Rico (co-official with English), Uruguay , and Venezuela . Spanish language has

10212-424: The normal rather than toward the normal as would be indicated when the refractive index is greater than unity. It can also be shown that the refractive index of a plasma, and hence the ionosphere, is frequency-dependent, see Dispersion (optics) . The critical frequency is the limiting frequency at or below which a radio wave is reflected by an ionospheric layer at vertical incidence . If the transmitted frequency

10323-734: The northwest of the African mainland. The Spanish spoken in the Canary Islands traces its origins back to the Castilian conquest in the 15th century , and, in addition to a resemblance to Western Andalusian speech patterns, it also features strong influence from the Spanish varieties spoken in the Americas, which in turn have also been influenced historically by Canarian Spanish. The Spanish spoken in North Africa by native bilingual speakers of Arabic or Berber who also speak Spanish as

10434-654: The other hand, currently uses the term español in its publications. However, from 1713 to 1923, it called the language castellano . The Diccionario panhispánico de dudas (a language guide published by the Royal Spanish Academy) states that, although the Royal Spanish Academy prefers to use the term español in its publications when referring to the Spanish language, both terms— español and castellano —are regarded as synonymous and equally valid. The term castellano

10545-533: The population. Many northern Moroccans have rudimentary knowledge of Spanish, with Spanish being particularly significant in areas adjacent to Ceuta and Melilla. Spanish also has a presence in the education system of the country (through either selected education centers implementing Spain's education system, primarily located in the North, or the availability of Spanish as foreign language subject in secondary education). In Western Sahara , formerly Spanish Sahara ,

10656-406: The recombination process prevails, since the gas molecules and ions are closer together. The balance between these two processes determines the quantity of ionization present. Ionization depends primarily on the Sun and its Extreme Ultraviolet (EUV) and X-ray irradiance which varies strongly with solar activity . The more magnetically active the Sun is, the more sunspot active regions there are on

10767-407: The sunspot cycle and geomagnetic activity. Geophysically, the state of the ionospheric plasma may be described by four parameters: electron density, electron and ion temperature and, since several species of ions are present, ionic composition . Radio propagation depends uniquely on electron density. Models are usually expressed as computer programs. The model may be based on basic physics of

10878-537: The term español (Spanish). According to the Royal Spanish Academy, español derives from the Occitan word espaignol and that, in turn, derives from the Vulgar Latin * hispaniolus ('of Hispania'). Hispania was the Roman name for the entire Iberian Peninsula . There are other hypotheses apart from the one suggested by the Royal Spanish Academy. Spanish philologist Ramón Menéndez Pidal suggested that

10989-537: The term ionosphere in a letter published only in 1969 in Nature : We have in quite recent years seen the universal adoption of the term 'stratosphere'..and..the companion term 'troposphere'... The term 'ionosphere', for the region in which the main characteristic is large scale ionisation with considerable mean free paths, appears appropriate as an addition to this series. In the early 1930s, test transmissions of Radio Luxembourg inadvertently provided evidence of

11100-444: The theories of Ramón Menéndez Pidal , local sociolects of Vulgar Latin evolved into Spanish, in the north of Iberia, in an area centered in the city of Burgos , and this dialect was later brought to the city of Toledo , where the written standard of Spanish was first developed, in the 13th century. In this formative stage, Spanish developed a strongly differing variant from its close cousin, Leonese , and, according to some authors,

11211-640: The third most used language on the Internet , after English and Chinese. Spanish is the official language of Spain . Upon the emergence of the Castilian Crown as the dominant power in the Iberian Peninsula by the end of the Middle Ages, the Romance vernacular associated with this polity became increasingly used in instances of prestige and influence, and the distinction between "Castilian" and "Spanish" started to become blurred. Hard policies imposing

11322-483: The topic of radio propagation of very long radio waves in the ionosphere. Vitaly Ginzburg has developed a theory of electromagnetic wave propagation in plasmas such as the ionosphere. In 1962, the Canadian satellite Alouette 1 was launched to study the ionosphere. Following its success were Alouette 2 in 1965 and the two ISIS satellites in 1969 and 1971, further AEROS-A and -B in 1972 and 1975, all for measuring

11433-537: The variation of the electron density from bottom of the ionosphere to the altitude of maximum density than in describing the total electron content (TEC). Since 1999 this model is "International Standard" for the terrestrial ionosphere (standard TS16457). Ionograms allow deducing, via computation, the true shape of the different layers. Nonhomogeneous structure of the electron / ion - plasma produces rough echo traces, seen predominantly at night and at higher latitudes, and during disturbed conditions. At mid-latitudes,

11544-585: The whole of Spain, in contrast to las demás lenguas españolas (lit. "the other Spanish languages "). Article III reads as follows: El castellano es la lengua española oficial del Estado. ... Las demás lenguas españolas serán también oficiales en las respectivas Comunidades Autónomas... Castilian is the official Spanish language of the State. ... The other Spanish languages shall also be official in their respective Autonomous Communities... The Royal Spanish Academy ( Real Academia Española ), on

11655-582: The world. Spanish is well represented in the humanities and social sciences . Spanish is also the third most used language on the internet by number of users after English and Chinese and the second most used language by number of websites after English. Spanish is used as an official language by many international organizations , including the United Nations , European Union , Organization of American States , Union of South American Nations , Community of Latin American and Caribbean States , African Union , among others. In Spain and some other parts of

11766-960: Was detected by Edward V. Appleton and Miles Barnett . The E s layer ( sporadic E-layer) is characterized by small, thin clouds of intense ionization, which can support reflection of radio waves, frequently up to 50 MHz and rarely up to 450 MHz. Sporadic-E events may last for just a few minutes to many hours. Sporadic E propagation makes VHF-operating by radio amateurs very exciting when long-distance propagation paths that are generally unreachable "open up" to two-way communication. There are multiple causes of sporadic-E that are still being pursued by researchers. This propagation occurs every day during June and July in northern hemisphere mid-latitudes when high signal levels are often reached. The skip distances are generally around 1,640 km (1,020 mi). Distances for one hop propagation can be anywhere from 900 to 2,500 km (560 to 1,550 mi). Multi-hop propagation over 3,500 km (2,200 mi)

11877-634: Was developed in the cities of Toledo , in the 13th to 16th centuries, and Madrid , from the 1570s. The development of the Spanish sound system from that of Vulgar Latin exhibits most of the changes that are typical of Western Romance languages , including lenition of intervocalic consonants (thus Latin vīta > Spanish vida ). The diphthongization of Latin stressed short e and o —which occurred in open syllables in French and Italian, but not at all in Catalan or Portuguese—is found in both open and closed syllables in Spanish, as shown in

11988-622: Was distinguished by a heavy Basque influence (see Iberian Romance languages ). This distinctive dialect spread to southern Spain with the advance of the Reconquista , and meanwhile gathered a sizable lexical influence from the Arabic of Al-Andalus , much of it indirectly, through the Romance Mozarabic dialects (some 4,000 Arabic -derived words, make up around 8% of the language today). The written standard for this new language

12099-713: Was followed by a vowel that did not diphthongize. The h- , still preserved in spelling, is now silent in most varieties of the language, although in some Andalusian and Caribbean dialects, it is still aspirated in some words. Because of borrowings from Latin and neighboring Romance languages, there are many f -/ h - doublets in modern Spanish: Fernando and Hernando (both Spanish for "Ferdinand"), ferrero and herrero (both Spanish for "smith"), fierro and hierro (both Spanish for "iron"), and fondo and hondo (both words pertaining to depth in Spanish, though fondo means "bottom", while hondo means "deep"); additionally, hacer ("to make")

12210-462: Was revoked by Michel Temer after the impeachment of Dilma Rousseff . In many border towns and villages along Paraguay and Uruguay, a mixed language known as Portuñol is spoken. Equatorial Guinea is the only Spanish-speaking country located entirely in Africa, with the language introduced during the Spanish colonial period . Enshrined in the constitution as an official language (alongside French and Portuguese), Spanish features prominently in

12321-515: Was using this technique to monitor the atmosphere above Australia and Antarctica. The ionosphere is a shell of electrons and electrically charged atoms and molecules that surrounds the Earth, stretching from a height of about 50 km (30 mi) to more than 1,000 km (600 mi). It exists primarily due to ultraviolet radiation from the Sun . The lowest part of the Earth's atmosphere ,

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