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179-448: In meteorology , a cloud is an aerosol consisting of a visible mass of miniature liquid droplets , frozen crystals , or other particles suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may compose the droplets and crystals. On Earth , clouds are formed as a result of saturation of the air when it is cooled to its dew point , or when it gains sufficient moisture (usually in
358-645: A GPS clock for data logging . Upper air data are of crucial importance for weather forecasting. The most widely used technique is launches of radiosondes . Supplementing the radiosondes a network of aircraft collection is organized by the World Meteorological Organization . Remote sensing , as used in meteorology, is the concept of collecting data from remote weather events and subsequently producing weather information. The common types of remote sensing are Radar , Lidar , and satellites (or photogrammetry ). Each collects data about
537-613: A definite article ("the"), a demonstrative adjective ("that"), and demonstrative pronoun . Other demonstratives are þēs ("this"), and ġeon ("that over there"). These words inflect for case, gender, and number. Adjectives have both strong and weak sets of endings, weak ones being used when a definite or possessive determiner is also present. Verbs conjugate for three persons : first, second, and third; two numbers: singular, plural; two tenses : present, and past; three moods : indicative , subjunctive , and imperative ; and are strong (exhibiting ablaut) or weak (exhibiting
716-616: A Problem in Mechanics and Physics that it should be possible to forecast weather from calculations based upon natural laws . It was not until later in the 20th century that advances in the understanding of atmospheric physics led to the foundation of modern numerical weather prediction . In 1922, Lewis Fry Richardson published "Weather Prediction By Numerical Process," after finding notes and derivations he worked on as an ambulance driver in World War I. He described how small terms in
895-498: A Roman geographer, formalized the climatic zone system. In 63–64 AD, Seneca wrote Naturales quaestiones . It was a compilation and synthesis of ancient Greek theories. However, theology was of foremost importance to Seneca, and he believed that phenomena such as lightning were tied to fate. The second book(chapter) of Pliny 's Natural History covers meteorology. He states that more than twenty ancient Greek authors studied meteorology. He did not make any personal contributions, and
1074-398: A back vowel ( /ɑ/ , /o/ , /u/ ) at the time of palatalization, as illustrated by the contrast between fisċ /fiʃ/ ('fish') and its plural fiscas /ˈfis.kɑs/ . But due to changes over time, a knowledge of the history of the word in question is needed to predict the pronunciation with certainty (for details, see palatalization ). In word-final position, the pronunciation of sċ
1253-429: A characteristic other than altitude. Clouds that form in the low level of the troposphere are generally of larger structure than those that form in the middle and high levels, so they can usually be identified by their forms and genus types using satellite photography alone. These clouds have low- to mid-level bases that form anywhere from near the surface to about 2,400 m (8,000 ft) and tops that can extend into
1432-604: A cloudlet of the species humilis that shows only slight vertical development. If the air becomes more unstable, the cloud tends to grow vertically into the species mediocris , then strongly convective congestus , the tallest cumulus species which is the same type that the International Civil Aviation Organization refers to as 'towering cumulus'. With highly unstable atmospheric conditions, large cumulus may continue to grow into even more strongly convective cumulonimbus calvus (essentially
1611-546: A common stratiform base. Castellanus resembles the turrets of a castle when viewed from the side, and can be found with stratocumuliform genera at any tropospheric altitude level and with limited-convective patches of high-level cirrus. Tufted clouds of the more detached floccus species are subdivisions of genus-types which may be cirriform or stratocumuliform in overall structure. They are sometimes seen with cirrus, cirrocumulus, altocumulus, and stratocumulus. A newly recognized species of stratocumulus or altocumulus has been given
1790-406: A dental suffix). Verbs have two infinitive forms: bare and bound; and two participles : present and past. The subjunctive has past and present forms. Finite verbs agree with subjects in person and number. The future tense , passive voice , and other aspects are formed with compounds. Adpositions are mostly before but are often after their object. If the object of an adposition is marked in
1969-506: A direct effect on climate change on Earth. They may reflect incoming rays from the Sun which can contribute to a cooling effect where and when these clouds occur, or trap longer wave radiation that reflects back up from the Earth's surface which can cause a warming effect. The altitude, form, and thickness of the clouds are the main factors that affect the local heating or cooling of the Earth and
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#17327647012012148-466: A farmer's potential harvest. In 1450, Leone Battista Alberti developed a swinging-plate anemometer , and was known as the first anemometer . In 1607, Galileo Galilei constructed a thermoscope . In 1611, Johannes Kepler wrote the first scientific treatise on snow crystals: "Strena Seu de Nive Sexangula (A New Year's Gift of Hexagonal Snow)." In 1643, Evangelista Torricelli invented the mercury barometer . In 1662, Sir Christopher Wren invented
2327-517: A following ⟨m⟩ or ⟨n⟩ . Modern editions of Old English manuscripts generally introduce some additional conventions. The modern forms of Latin letters are used, including ⟨g⟩ instead of insular G , ⟨s⟩ instead of insular S and long S , and others which may differ considerably from the insular script, notably ⟨e⟩ , ⟨f⟩ and ⟨r⟩ . Macrons are used to indicate long vowels, where usually no distinction
2506-467: A friction that led to the erosion of the complicated inflectional word endings. Simeon Potter notes: No less far-reaching was the influence of Scandinavian upon the inflexional endings of English in hastening that wearing away and leveling of grammatical forms which gradually spread from north to south. It was, after all, a salutary influence. The gain was greater than the loss. There was a gain in directness, in clarity, and in strength. The strength of
2685-485: A gale was expected. FitzRoy coined the term "weather forecast" and tried to separate scientific approaches from prophetic ones. Over the next 50 years, many countries established national meteorological services. The India Meteorological Department (1875) was established to follow tropical cyclone and monsoon . The Finnish Meteorological Central Office (1881) was formed from part of Magnetic Observatory of Helsinki University . Japan's Tokyo Meteorological Observatory,
2864-630: A group of meteorologists in Norway led by Vilhelm Bjerknes developed the Norwegian cyclone model that explains the generation, intensification and ultimate decay (the life cycle) of mid-latitude cyclones , and introduced the idea of fronts , that is, sharply defined boundaries between air masses . The group included Carl-Gustaf Rossby (who was the first to explain the large scale atmospheric flow in terms of fluid dynamics ), Tor Bergeron (who first determined how rain forms) and Jacob Bjerknes . In
3043-486: A legitimate branch of physics. In the 18th century, the invention of the thermometer and barometer allowed for more accurate measurements of temperature and pressure, leading to a better understanding of atmospheric processes. This century also saw the birth of the first meteorological society, the Societas Meteorologica Palatina in 1780. In the 19th century, advances in technology such as
3222-401: A major focus on weather forecasting . The study of meteorology dates back millennia , though significant progress in meteorology did not begin until the 18th century. The 19th century saw modest progress in the field after weather observation networks were formed across broad regions. Prior attempts at prediction of weather depended on historical data. It was not until after the elucidation of
3401-547: A narrower line of clouds, which are mostly stratocumuliform, cumuliform, or cumulonimbiform depending on the stability of the warm airmass just ahead of the front. A third source of lift is wind circulation forcing air over a physical barrier such as a mountain ( orographic lift ). If the air is generally stable, nothing more than lenticular cap clouds form. However, if the air becomes sufficiently moist and unstable, orographic showers or thunderstorms may appear. Clouds formed by any of these lifting agents are initially seen in
3580-473: A parcel of air containing invisible water vapor to rise and cool to its dew point, the temperature at which the air becomes saturated. The main mechanism behind this process is adiabatic cooling. As the air is cooled to its dew point and becomes saturated, water vapor normally condenses to form cloud drops. This condensation normally occurs on cloud condensation nuclei such as salt or dust particles that are small enough to be held aloft by normal circulation of
3759-530: A period of 700 years, from the Anglo-Saxon settlement of Britain in the 5th century to the late 11th century, some time after the Norman invasion . While indicating that the establishment of dates is an arbitrary process, Albert Baugh dates Old English from 450 to 1150, a period of full inflections, a synthetic language . Perhaps around 85% of Old English words are no longer in use, but those that survived are
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#17327647012013938-496: A period up to a year. His system was based on dividing the year by the setting and the rising of the Pleiad, halves into solstices and equinoxes, and the continuity of the weather for those periods. He also divided months into the new moon, fourth day, eighth day and full moon, in likelihood of a change in the weather occurring. The day was divided into sunrise, mid-morning, noon, mid-afternoon and sunset, with corresponding divisions of
4117-409: A powerful "ripple" in the atmosphere, the cloud may be "surfed" in glider aircraft. More general airmass instability in the troposphere tends to produce clouds of the more freely convective cumulus genus type, whose species are mainly indicators of degrees of atmospheric instability and resultant vertical development of the clouds. A cumulus cloud initially forms in the low level of the troposphere as
4296-950: A snapshot of a variety of weather conditions at one single location and are usually at a weather station , a ship or a weather buoy . The measurements taken at a weather station can include any number of atmospheric observables. Usually, temperature, pressure , wind measurements, and humidity are the variables that are measured by a thermometer, barometer, anemometer, and hygrometer, respectively. Professional stations may also include air quality sensors ( carbon monoxide , carbon dioxide , methane , ozone , dust , and smoke ), ceilometer (cloud ceiling), falling precipitation sensor, flood sensor , lightning sensor , microphone ( explosions , sonic booms , thunder ), pyranometer / pyrheliometer / spectroradiometer (IR/Vis/UV photodiodes ), rain gauge / snow gauge , scintillation counter ( background radiation , fallout , radon ), seismometer ( earthquakes and tremors), transmissometer (visibility), and
4475-524: A specific altitude level or form, and can therefore be common to more than one genus or species. All cloud varieties fall into one of two main groups. One group identifies the opacities of particular low and mid-level cloud structures and comprises the varieties translucidus (thin translucent), perlucidus (thick opaque with translucent or very small clear breaks), and opacus (thick opaque). These varieties are always identifiable for cloud genera and species with variable opacity. All three are associated with
4654-527: A surface-based observer (cloud fields usually being visible only from a significant altitude above the formations). These varieties are not always present with the genera and species with which they are otherwise associated, but only appear when atmospheric conditions favor their formation. Intortus and vertebratus varieties occur on occasion with cirrus fibratus. They are respectively filaments twisted into irregular shapes, and those that are arranged in fishbone patterns, usually by uneven wind currents that favor
4833-409: A very tall congestus cloud that produces thunder), then ultimately into the species capillatus when supercooled water droplets at the top of the cloud turn into ice crystals giving it a cirriform appearance. Genus and species types are further subdivided into varieties whose names can appear after the species name to provide a fuller description of a cloud. Some cloud varieties are not restricted to
5012-523: Is a feature seen with clouds producing precipitation that evaporates before reaching the ground, these being of the genera cirrocumulus, altocumulus, altostratus, nimbostratus, stratocumulus, cumulus, and cumulonimbus. When the precipitation reaches the ground without completely evaporating, it is designated as the feature praecipitatio . This normally occurs with altostratus opacus, which can produce widespread but usually light precipitation, and with thicker clouds that show significant vertical development. Of
5191-559: Is a species made of semi-merged filaments that are transitional to or from cirrus. Mid-level altostratus and multi-level nimbostratus always have a flat or diffuse appearance and are therefore not subdivided into species. Low stratus is of the species nebulosus except when broken up into ragged sheets of stratus fractus (see below). Cirriform clouds have three non-convective species that can form in stable airmass conditions. Cirrus fibratus comprise filaments that may be straight, wavy, or occasionally twisted by wind shear. The species uncinus
5370-607: Is also responsible for twilight in Opticae thesaurus ; he estimated that twilight begins when the sun is 19 degrees below the horizon , and also used a geometric determination based on this to estimate the maximum possible height of the Earth's atmosphere as 52,000 passim (about 49 miles, or 79 km). Adelard of Bath was one of the early translators of the classics. He also discussed meteorological topics in his Quaestiones naturales . He thought dense air produced propulsion in
5549-552: Is also sparse early Northumbrian evidence of a sixth case: the locative . The evidence comes from Northumbrian Runic texts (e.g., ᚩᚾ ᚱᚩᛞᛁ on rodi "on the Cross"). Adjectives agree with nouns in case, gender, and number, and can be either strong or weak. Pronouns and sometimes participles agree in case, gender, and number. First-person and second- person personal pronouns occasionally distinguish dual-number forms. The definite article sē and its inflections serve as
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5728-422: Is as follows. The sounds enclosed in parentheses in the chart above are not considered to be phonemes : The above system is largely similar to that of Modern English , except that [ç, x, ɣ, l̥, n̥, r̥] (and [ʍ] for most speakers ) have generally been lost, while the voiced affricate and fricatives (now also including /ʒ/ ) have become independent phonemes, as has /ŋ/ . The open back rounded vowel [ɒ]
5907-407: Is caused by localized downdrafts that create circular holes in the form of a honeycomb or net. It is occasionally seen with cirrocumulus and altocumulus of the species stratiformis, castellanus, and floccus, and with stratocumulus of the species stratiformis and castellanus. It is possible for some species to show combined varieties at one time, especially if one variety is opacity-based and the other
6086-621: Is evidenced by the continued variation between their successors in Middle and Modern English. In fact, what would become the standard forms of Middle English and of Modern English are descended from Mercian rather than West Saxon, while Scots developed from the Northumbrian dialect. It was once claimed that, owing to its position at the heart of the Kingdom of Wessex, the relics of Anglo-Saxon accent, idiom and vocabulary were best preserved in
6265-668: Is followed by Middle English (1150 to 1500), Early Modern English (1500 to 1650) and finally Modern English (after 1650), and in Scotland Early Scots (before 1450), Middle Scots ( c. 1450 to 1700) and Modern Scots (after 1700). Just as Modern English is not monolithic, Old English varied according to place. Despite the diversity of language of the Germanic-speaking migrants who established Old English in England and southeastern Scotland, it
6444-835: Is much freer. The oldest Old English inscriptions were written using a runic system , but from about the 8th century this was replaced by a version of the Latin alphabet . Englisċ , from which the word English is derived, means 'pertaining to the Angles '. The Angles were one of the Germanic tribes who settled in many parts of Britain in the 5th century. By the 9th century, all speakers of Old English, including those who claimed Saxon or Jutish ancestry, could be referred to as Englisċ . This name probably either derives from Proto-Germanic *anguz , which referred to narrowness, constriction or anxiety, perhaps referring to shallow waters near
6623-487: Is not mandatory to be hired by the media. Each science has its own unique sets of laboratory equipment. In the atmosphere, there are many things or qualities of the atmosphere that can be measured. Rain, which can be observed, or seen anywhere and anytime was one of the first atmospheric qualities measured historically. Also, two other accurately measured qualities are wind and humidity. Neither of these can be seen but can be felt. The devices to measure these three sprang up in
6802-552: Is now known as Middle English in England and Early Scots in Scotland. Old English developed from a set of Anglo-Frisian or Ingvaeonic dialects originally spoken by Germanic tribes traditionally known as the Angles , Saxons and Jutes . As the Germanic settlers became dominant in England, their language replaced the languages of Roman Britain : Common Brittonic , a Celtic language ; and Latin , brought to Britain by
6981-415: Is one that has spread out into a clear anvil shape as a result of rising air currents hitting the stability layer at the tropopause where the air no longer continues to get colder with increasing altitude. The mamma feature forms on the bases of clouds as downward-facing bubble-like protuberances caused by localized downdrafts within the cloud. It is also sometimes called mammatus , an earlier version of
7160-438: Is pattern-based. An example of this would be a layer of altocumulus stratiformis arranged in seemingly converging rows separated by small breaks. The full technical name of a cloud in this configuration would be altocumulus stratiformis radiatus perlucidus , which would identify respectively its genus, species, and two combined varieties. Supplementary features and accessory clouds are not further subdivisions of cloud types below
7339-864: Is possible to reconstruct proto-Old English as a fairly unitary language. For the most part, the differences between the attested regional dialects of Old English developed within England and southeastern Scotland, rather than on the Mainland of Europe. Although from the tenth century Old English writing from all regions tended to conform to a written standard based on Late West Saxon, in speech Old English continued to exhibit much local and regional variation, which remained in Middle English and to some extent Modern English dialects . The four main dialectal forms of Old English were Mercian , Northumbrian , Kentish , and West Saxon . Mercian and Northumbrian are together referred to as Anglian . In terms of geography
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7518-434: Is replaced by ⟨þ⟩ ). In contrast with Modern English orthography , Old English spelling was reasonably regular , with a mostly predictable correspondence between letters and phonemes . There were not usually any silent letters —in the word cniht , for example, both the ⟨c⟩ and ⟨h⟩ were pronounced ( /knixt ~ kniçt/ ) unlike the ⟨k⟩ and ⟨gh⟩ in
7697-425: Is similar but has upturned hooks at the ends. Cirrus spissatus appear as opaque patches that can show light gray shading. Stratocumuliform genus-types (cirrocumulus, altocumulus, and stratocumulus) that appear in mostly stable air with limited convection have two species each. The stratiformis species normally occur in extensive sheets or in smaller patches where there is only minimal convective activity. Clouds of
7876-454: The 22° and 46° halos . The ancient Greeks were the first to make theories about the weather. Many natural philosophers studied the weather. However, as meteorological instruments did not exist, the inquiry was largely qualitative, and could only be judged by more general theoretical speculations. Herodotus states that Thales predicted the solar eclipse of 585 BC. He studied Babylonian equinox tables. According to Seneca, he gave
8055-413: The Earth's magnetic field lines. In 1494, Christopher Columbus experienced a tropical cyclone, which led to the first written European account of a hurricane. In 1686, Edmund Halley presented a systematic study of the trade winds and monsoons and identified solar heating as the cause of atmospheric motions. In 1735, an ideal explanation of global circulation through study of the trade winds
8234-644: The Kitab al-Nabat (Book of Plants), in which he deals with the application of meteorology to agriculture during the Arab Agricultural Revolution . He describes the meteorological character of the sky, the planets and constellations , the sun and moon , the lunar phases indicating seasons and rain, the anwa ( heavenly bodies of rain), and atmospheric phenomena such as winds, thunder, lightning, snow, floods, valleys, rivers, lakes. In 1021, Alhazen showed that atmospheric refraction
8413-652: The Latin alphabet was introduced and adapted for the writing of Old English , replacing the earlier runic system. Nonetheless, the largest transfer of Latin-based (mainly Old French ) words into English occurred after the Norman Conquest of 1066, and thus in the Middle English rather than the Old English period. Another source of loanwords was Old Norse , which came into contact with Old English via
8592-491: The Roman conquest . Old English had four main dialects, associated with particular Anglo-Saxon kingdoms : Kentish , Mercian , Northumbrian , and West Saxon . It was West Saxon that formed the basis for the literary standard of the later Old English period, although the dominant forms of Middle and Modern English would develop mainly from Mercian, and Scots from Northumbrian. The speech of eastern and northern parts of England
8771-628: The Smithsonian Institution began to establish an observation network across the United States under the leadership of Joseph Henry . Similar observation networks were established in Europe at this time. The Reverend William Clement Ley was key in understanding of cirrus clouds and early understandings of Jet Streams . Charles Kenneth Mackinnon Douglas , known as 'CKM' Douglas read Ley's papers after his death and carried on
8950-578: The atmospheric sciences . Meteorology and hydrology compose the interdisciplinary field of hydrometeorology . The interactions between Earth's atmosphere and its oceans are part of a coupled ocean-atmosphere system. Meteorology has application in many diverse fields such as the military, energy production, transport, agriculture, and construction. The word meteorology is from the Ancient Greek μετέωρος metéōros ( meteor ) and -λογία -logia ( -(o)logy ), meaning "the study of things high in
9129-603: The dialect of Somerset . For details of the sound differences between the dialects, see Phonological history of Old English § Dialects . The language of the Anglo-Saxon settlers appears not to have been significantly affected by the native British Celtic languages which it largely displaced . The number of Celtic loanwords introduced into the language is very small, although dialect and toponymic terms are more often retained in western language contact zones (Cumbria, Devon, Welsh Marches and Borders and so on) than in
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#17327647012019308-417: The heat capacity of gases varies inversely with atomic weight . In 1824, Sadi Carnot analyzed the efficiency of steam engines using caloric theory; he developed the notion of a reversible process and, in postulating that no such thing exists in nature, laid the foundation for the second law of thermodynamics . In 1716, Edmund Halley suggested that aurorae are caused by "magnetic effluvia" moving along
9487-609: The kingdom of Northumbria . Other parts of the island continued to use Celtic languages ( Gaelic – and perhaps some Pictish – in most of Scotland, Medieval Cornish all over Cornwall and in adjacent parts of Devon , Cumbric perhaps to the 12th century in parts of Cumbria , and Welsh in Wales and possibly also on the English side of the Anglo-Welsh border ); except in the areas of Scandinavian settlements, where Old Norse
9666-405: The lenticularis species tend to have lens-like shapes tapered at the ends. They are most commonly seen as orographic mountain- wave clouds , but can occur anywhere in the troposphere where there is strong wind shear combined with sufficient airmass stability to maintain a generally flat cloud structure. These two species can be found in the high, middle, or low levels of the troposphere depending on
9845-637: The phlogiston theory . In 1777, Antoine Lavoisier discovered oxygen and developed an explanation for combustion. In 1783, in Lavoisier's essay "Reflexions sur le phlogistique," he deprecates the phlogiston theory and proposes a caloric theory . In 1804, John Leslie observed that a matte black surface radiates heat more effectively than a polished surface, suggesting the importance of black-body radiation . In 1808, John Dalton defended caloric theory in A New System of Chemistry and described how it combines with matter, especially gases; he proposed that
10024-752: The polar regions , 5,000 to 12,200 m (16,500 to 40,000 ft) in the temperate regions , and 6,100 to 18,300 m (20,000 to 60,000 ft) in the tropics . All cirriform clouds are classified as high, thus constitute a single genus cirrus (Ci). Stratocumuliform and stratiform clouds in the high altitude range carry the prefix cirro- , yielding the respective genus names cirrocumulus (Cc) and cirrostratus (Cs). If limited-resolution satellite images of high clouds are analyzed without supporting data from direct human observations, distinguishing between individual forms or genus types becomes impossible, and they are collectively identified as high-type (or informally as cirrus-type , though not all high clouds are of
10203-422: The 8th century, the runic system came to be supplanted by a (minuscule) half-uncial script of the Latin alphabet introduced by Irish Christian missionaries. This was replaced by Insular script , a cursive and pointed version of the half-uncial script. This was used until the end of the 12th century when continental Carolingian minuscule (also known as Caroline ) replaced the insular. The Latin alphabet of
10382-528: The Aristotelian method. The work of Theophrastus remained a dominant influence in weather forecasting for nearly 2,000 years. Meteorology continued to be studied and developed over the centuries, but it was not until the Renaissance in the 14th to 17th centuries that significant advancements were made in the field. Scientists such as Galileo and Descartes introduced new methods and ideas, leading to
10561-406: The English language; some of them, such as Pope Gregory I 's treatise Pastoral Care , appear to have been translated by Alfred himself. In Old English, typical of the development of literature, poetry arose before prose, but Alfred chiefly inspired the growth of prose. A later literary standard, dating from the late 10th century, arose under the influence of Bishop Æthelwold of Winchester , and
10740-520: The Great was the first to propose that each drop of falling rain had the form of a small sphere, and that this form meant that the rainbow was produced by light interacting with each raindrop. Roger Bacon was the first to calculate the angular size of the rainbow. He stated that a rainbow summit cannot appear higher than 42 degrees above the horizon. In the late 13th century and early 14th century, Kamāl al-Dīn al-Fārisī and Theodoric of Freiberg were
10919-556: The Great . From that time on, the West Saxon dialect (then in the form now known as Early West Saxon) became standardised as the language of government, and as the basis for the many works of literature and religious materials produced or translated from Latin in that period. The later literary standard known as Late West Saxon (see History , above), although centred in the same region of the country, appears not to have been directly descended from Alfred's Early West Saxon. For example,
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#173276470120111098-519: The Greek word meteoros , meaning 'high in the sky'. From that word came the modern term meteorology , the study of clouds and weather. Meteorologica was based on intuition and simple observation, but not on what is now considered the scientific method. Nevertheless, it was the first known work that attempted to treat a broad range of meteorological topics in a systematic way, especially the hydrological cycle . After centuries of speculative theories about
11277-541: The Modification of Clouds , in which he assigns cloud types Latin names. In 1806, Francis Beaufort introduced his system for classifying wind speeds . Near the end of the 19th century the first cloud atlases were published, including the International Cloud Atlas , which has remained in print ever since. The April 1960 launch of the first successful weather satellite , TIROS-1 , marked
11456-410: The Northumbrian dialect retained /i(ː)o̯/ , which had merged with /e(ː)o̯/ in West Saxon. For more on dialectal differences, see Phonological history of Old English (dialects) . Some of the principal sound changes occurring in the pre-history and history of Old English were the following: For more details of these processes, see the main article, linked above. For sound changes before and after
11635-880: The Northumbrian region lay north of the Humber River; the Mercian lay north of the Thames and south of the Humber River; West Saxon lay south and southwest of the Thames; and the smallest, Kentish region lay southeast of the Thames, a small corner of England. The Kentish region, settled by the Jutes from Jutland, has the scantest literary remains. The term West Saxon actually is represented by two different dialects: Early West Saxon and Late West Saxon. Hogg has suggested that these two dialects would be more appropriately named Alfredian Saxon and Æthelwoldian Saxon, respectively, so that
11814-467: The Old English period is also often attributed to Norse influence. The influence of Old Norse certainly helped move English from a synthetic language along the continuum to a more analytic word order , and Old Norse most likely made a greater impact on the English language than any other language. The eagerness of Vikings in the Danelaw to communicate with their Anglo-Saxon neighbours produced
11993-478: The Old English period, see Phonological history of English . Nouns decline for five cases : nominative , accusative , genitive , dative , instrumental ; three genders : masculine, feminine, neuter; and two numbers : singular, and plural; and are strong or weak. The instrumental is vestigial and only used with the masculine and neuter singular and often replaced by the dative . Only pronouns and strong adjectives retain separate instrumental forms. There
12172-526: The Scandinavian rulers and settlers in the Danelaw from the late 9th century, and during the rule of Cnut and other Danish kings in the early 11th century. Many place names in eastern and northern England are of Scandinavian origin. Norse borrowings are relatively rare in Old English literature, being mostly terms relating to government and administration. The literary standard, however,
12351-606: The Viking influence on Old English appears from the fact that the indispensable elements of the language – pronouns , modals , comparatives , pronominal adverbs (like hence and together ), conjunctions and prepositions – show the most marked Danish influence; the best evidence of Scandinavian influence appears in the extensive word borrowings because, as Jespersen indicates, no texts exist in either Scandinavia or Northern England from this time to give certain evidence of an influence on syntax. The effect of Old Norse on Old English
12530-476: The advancement in weather forecasting and satellite technology, meteorology has become an integral part of everyday life, and is used for many purposes such as aviation, agriculture, and disaster management. In 1441, King Sejong 's son, Prince Munjong of Korea, invented the first standardized rain gauge . These were sent throughout the Joseon dynasty of Korea as an official tool to assess land taxes based upon
12709-437: The air to its dew point. Conductive, radiational, and evaporative cooling require no lifting mechanism and can cause condensation at surface level resulting in the formation of fog . Several main sources of water vapor can be added to the air as a way of achieving saturation without any cooling process: evaporation from surface water or moist ground, precipitation or virga , and transpiration from plants. Classification in
12888-962: The air". Early attempts at predicting weather were often related to prophecy and divining , and were sometimes based on astrological ideas. Ancient religions believed meteorological phenomena to be under the control of the gods. The ability to predict rains and floods based on annual cycles was evidently used by humans at least from the time of agricultural settlement if not earlier. Early approaches to predicting weather were based on astrology and were practiced by priests. The Egyptians had rain-making rituals as early as 3500 BC. Ancient Indian Upanishads contain mentions of clouds and seasons . The Samaveda mentions sacrifices to be performed when certain phenomena were noticed. Varāhamihira 's classical work Brihatsamhita , written about 500 AD, provides evidence of weather observation. Cuneiform inscriptions on Babylonian tablets included associations between thunder and rain. The Chaldeans differentiated
13067-445: The air. One agent is the convective upward motion of air caused by daytime solar heating at surface level. Low level airmass instability allows for the formation of cumuliform clouds in the troposphere that can produce showers if the air is sufficiently moist. On moderately rare occasions, convective lift can be powerful enough to penetrate the tropopause and push the cloud top into the stratosphere. Frontal and cyclonic lift occur in
13246-401: The altitude at which each initially forms, and are also more informally characterized as multi-level or vertical . Most of the ten genera derived by this method of classification can be subdivided into species and further subdivided into varieties . Very low stratiform clouds that extend down to the Earth's surface are given the common names fog and mist , but have no Latin names. In
13425-471: The altitude levels. Ancient cloud studies were not made in isolation, but were observed in combination with other weather elements and even other natural sciences. Around 340 BC, Greek philosopher Aristotle wrote Meteorologica , a work which represented the sum of knowledge of the time about natural science, including weather and climate. For the first time, precipitation and the clouds from which precipitation fell were called meteors, which originate from
13604-498: The appendix Les Meteores , he applied these principles to meteorology. He discussed terrestrial bodies and vapors which arise from them, proceeding to explain the formation of clouds from drops of water, and winds, clouds then dissolving into rain, hail and snow. He also discussed the effects of light on the rainbow. Descartes hypothesized that all bodies were composed of small particles of different shapes and interwovenness. All of his theories were based on this hypothesis. He explained
13783-412: The atmosphere can be divided into distinct areas that depend on both time and spatial scales. At one extreme of this scale is climatology. In the timescales of hours to days, meteorology separates into micro-, meso-, and synoptic scale meteorology. Respectively, the geospatial size of each of these three scales relates directly with the appropriate timescale. Other subclassifications are used to describe
13962-456: The atmosphere from a remote location and, usually, stores the data where the instrument is located. Radar and Lidar are not passive because both use EM radiation to illuminate a specific portion of the atmosphere. Weather satellites along with more general-purpose Earth-observing satellites circling the earth at various altitudes have become an indispensable tool for studying a wide range of phenomena from forest fires to El Niño . The study of
14141-484: The atmosphere. Clouds that form above the troposphere are too scarce and too thin to have any influence on climate change. Clouds are the main uncertainty in climate sensitivity . The origin of the term "cloud" can be found in the Old English words clud or clod , meaning a hill or a mass of stone. Around the beginning of the 13th century, the word came to be used as a metaphor for rain clouds, because of
14320-506: The basic elements of Modern English vocabulary. Old English is a West Germanic language , and developed out of Ingvaeonic (also known as North Sea Germanic) dialects from the 5th century. It came to be spoken over most of the territory of the Anglo-Saxon kingdoms which became the Kingdom of England . This included most of present-day England, as well as part of what is now southeastern Scotland , which for several centuries belonged to
14499-671: The beginning of the age where weather information became available globally. In 1648, Blaise Pascal rediscovered that atmospheric pressure decreases with height, and deduced that there is a vacuum above the atmosphere. In 1738, Daniel Bernoulli published Hydrodynamics , initiating the Kinetic theory of gases and established the basic laws for the theory of gases. In 1761, Joseph Black discovered that ice absorbs heat without changing its temperature when melting. In 1772, Black's student Daniel Rutherford discovered nitrogen , which he called phlogisticated air , and together they developed
14678-559: The beginnings of the compound tenses of Modern English . Old English verbs include strong verbs , which form the past tense by altering the root vowel, and weak verbs , which use a suffix such as -de . As in Modern English, and peculiar to the Germanic languages, the verbs formed two great classes: weak (regular), and strong (irregular). Like today, Old English had fewer strong verbs, and many of these have over time decayed into weak forms. Then, as now, dental suffixes indicated
14857-460: The best known products of meteorologists for the public, weather presenters on radio and television are not necessarily professional meteorologists. They are most often reporters with little formal meteorological training, using unregulated titles such as weather specialist or weatherman . The American Meteorological Society and National Weather Association issue "Seals of Approval" to weather broadcasters who meet certain requirements but this
15036-494: The borrowing of individual Latin words based on which patterns of sound change they have undergone. Some Latin words had already been borrowed into the Germanic languages before the ancestral Angles and Saxons left continental Europe for Britain. More entered the language when the Anglo-Saxons were converted to Christianity and Latin-speaking priests became influential. It was also through Irish Christian missionaries that
15215-401: The calculations led to unrealistic results. Though numerical analysis later found that this was due to numerical instability . Starting in the 1950s, numerical forecasts with computers became feasible. The first weather forecasts derived this way used barotropic (single-vertical-level) models, and could successfully predict the large-scale movement of midlatitude Rossby waves , that is,
15394-444: The chaotic nature of the atmosphere. Mathematical models used to predict the long term weather of the Earth ( climate models ), have been developed that have a resolution today that are as coarse as the older weather prediction models. These climate models are used to investigate long-term climate shifts, such as what effects might be caused by human emission of greenhouse gases . Meteorologists are scientists who study and work in
15573-413: The church and princes. This was supported by scientists like Johannes Muller , Leonard Digges , and Johannes Kepler . However, there were skeptics. In the 14th century, Nicole Oresme believed that weather forecasting was possible, but that the rules for it were unknown at the time. Astrological influence in meteorology persisted until the eighteenth century. Gerolamo Cardano 's De Subilitate (1550)
15752-458: The cirrus form or genus). Nonvertical clouds in the middle level are prefixed by alto- , yielding the genus names altocumulus (Ac) for stratocumuliform types and altostratus (As) for stratiform types. These clouds can form as low as 2,000 m (6,500 ft) above surface at any latitude, but may be based as high as 4,000 m (13,000 ft) near the poles, 7,000 m (23,000 ft) at midlatitudes, and 7,600 m (25,000 ft) in
15931-616: The climate with public health. During the Age of Enlightenment meteorology tried to rationalise traditional weather lore, including astrological meteorology. But there were also attempts to establish a theoretical understanding of weather phenomena. Edmond Halley and George Hadley tried to explain trade winds . They reasoned that the rising mass of heated equator air is replaced by an inflow of cooler air from high latitudes. A flow of warm air at high altitude from equator to poles in turn established an early picture of circulation. Frustration with
16110-422: The clouds and winds extended up to 111 miles, but Posidonius thought that they reached up to five miles, after which the air is clear, liquid and luminous. He closely followed Aristotle's theories. By the end of the second century BC, the center of science shifted from Athens to Alexandria , home to the ancient Library of Alexandria . In the 2nd century AD, Ptolemy 's Almagest dealt with meteorology, because it
16289-499: The cluster ending in the palatal affricate is sometimes written ⟨nċġ⟩ (or ⟨nġċ⟩ ) by modern editors. Between vowels in the middle of a word, the pronunciation can be either a palatalized geminate /ʃː/ , as in fisċere /ˈfiʃ.ʃe.re/ ('fisherman') and wȳsċan , /ˈwyːʃ.ʃɑn 'to wish'), or an unpalatalized consonant sequence /sk/ , as in āscian /ˈɑːs.ki.ɑn/ ('to ask'). The pronunciation /sk/ occurs when ⟨sc⟩ had been followed by
16468-461: The coast, or else it may derive from a related word *angô which could refer to curve or hook shapes including fishing hooks. Concerning the second option, it has been hypothesised that the Angles acquired their name either because they lived on a curved promontory of land shaped like a fishhook , or else because they were fishermen (anglers). Old English was not static, and its usage covered
16647-421: The dative case, an adposition may conceivably be located anywhere in the sentence. Remnants of the Old English case system in Modern English are in the forms of a few pronouns (such as I/me/mine , she/her , who/whom/whose ) and in the possessive ending -'s , which derives from the masculine and neuter genitive ending -es . The modern English plural ending -(e)s derives from the Old English -as , but
16826-495: The description of what is now known as the hydrologic cycle . His work would remain an authority on meteorology for nearly 2,000 years. The book De Mundo (composed before 250 BC or between 350 and 200 BC) noted: After Aristotle, progress in meteorology stalled for a long time. Theophrastus compiled a book on weather forecasting, called the Book of Signs , as well as On Winds . He gave hundreds of signs for weather phenomena for
17005-651: The early study of weather systems. Nineteenth century researchers in meteorology were drawn from military or medical backgrounds, rather than trained as dedicated scientists. In 1854, the United Kingdom government appointed Robert FitzRoy to the new office of Meteorological Statist to the Board of Trade with the task of gathering weather observations at sea. FitzRoy's office became the United Kingdom Meteorological Office in 1854,
17184-431: The east. However, various suggestions have been made concerning possible influence that Celtic may have had on developments in English syntax in the post–Old English period, such as the regular progressive construction and analytic word order , as well as the eventual development of the periphrastic auxiliary verb do . These ideas have generally not received widespread support from linguists, particularly as many of
17363-487: The existence of a circulation cell in the mid-latitudes, and the air within deflected by the Coriolis force resulting in the prevailing westerly winds. Late in the 19th century, the motion of air masses along isobars was understood to be the result of the large-scale interaction of the pressure gradient force and the deflecting force. By 1912, this deflecting force was named the Coriolis effect. Just after World War I,
17542-471: The explanation that the cause of the Nile 's annual floods was due to northerly winds hindering its descent by the sea. Anaximander and Anaximenes thought that thunder and lightning was caused by air smashing against the cloud, thus kindling the flame. Early meteorological theories generally considered that there was a fire-like substance in the atmosphere. Anaximander defined wind as a flowing of air, but this
17721-443: The field of meteorology. The American Meteorological Society publishes and continually updates an authoritative electronic Meteorology Glossary . Meteorologists work in government agencies , private consulting and research services, industrial enterprises, utilities, radio and television stations , and in education . In the United States, meteorologists held about 10,000 jobs in 2018. Although weather forecasts and warnings are
17900-664: The first weather observing network, that consisted of meteorological stations in Florence , Cutigliano , Vallombrosa , Bologna , Parma , Milan , Innsbruck , Osnabrück , Paris and Warsaw . The collected data were sent to Florence at regular time intervals. In the 1660s Robert Hooke of the Royal Society of London sponsored networks of weather observers. Hippocrates ' treatise Airs, Waters, and Places had linked weather to disease. Thus early meteorologists attempted to correlate weather patterns with epidemic outbreaks, and
18079-400: The first time, a practical method for quickly gathering surface weather observations from a wide area. This data could be used to produce maps of the state of the atmosphere for a region near the Earth's surface and to study how these states evolved through time. To make frequent weather forecasts based on these data required a reliable network of observations, but it was not until 1849 that
18258-407: The first to give the correct explanations for the primary rainbow phenomenon. Theoderic went further and also explained the secondary rainbow. By the middle of the sixteenth century, meteorology had developed along two lines: theoretical science based on Meteorologica , and astrological weather forecasting. The pseudoscientific prediction by natural signs became popular and enjoyed protection of
18437-633: The first weather forecasts and temperature predictions. In the 20th and 21st centuries, with the advent of computer models and big data, meteorology has become increasingly dependent on numerical methods and computer simulations. This has greatly improved weather forecasting and climate predictions. Additionally, meteorology has expanded to include other areas such as air quality, atmospheric chemistry, and climatology. The advancement in observational, theoretical and computational technologies has enabled ever more accurate weather predictions and understanding of weather pattern and air pollution. In current time, with
18616-603: The forerunner of the Japan Meteorological Agency , began constructing surface weather maps in 1883. The United States Weather Bureau (1890) was established under the United States Department of Agriculture . The Australian Bureau of Meteorology (1906) was established by a Meteorology Act to unify existing state meteorological services. In 1904, Norwegian scientist Vilhelm Bjerknes first argued in his paper Weather Forecasting as
18795-456: The form of water vapor ) from an adjacent source to raise the dew point to the ambient temperature . Clouds are seen in the Earth's homosphere , which includes the troposphere , stratosphere , and mesosphere . Nephology is the science of clouds, which is undertaken in the cloud physics branch of meteorology . There are two methods of naming clouds in their respective layers of the homosphere, Latin and common name . Genus types in
18974-527: The form of wind. He explained thunder by saying that it was due to ice colliding in clouds, and in Summer it melted. In the thirteenth century, Aristotelian theories reestablished dominance in meteorology. For the next four centuries, meteorological work by and large was mostly commentary . It has been estimated over 156 commentaries on the Meteorologica were written before 1650. Experimental evidence
19153-455: The formation and behavior of clouds, the first truly scientific studies were undertaken by Luke Howard in England and Jean-Baptiste Lamarck in France. Howard was a methodical observer with a strong grounding in the Latin language, and used his background to formally classify the various tropospheric cloud types during 1802. He believed that scientific observations of the changing cloud forms in
19332-422: The formation of these varieties. The variety radiatus is associated with cloud rows of a particular type that appear to converge at the horizon. It is sometimes seen with the fibratus and uncinus species of cirrus, the stratiformis species of altocumulus and stratocumulus, the mediocris and sometimes humilis species of cumulus, and with the genus altostratus. Another variety, duplicatus (closely spaced layers of
19511-645: The former diphthong /iy/ tended to become monophthongised to /i/ in EWS, but to /y/ in LWS. Due to the centralisation of power and the destruction wrought by Viking invasions, there is relatively little written record of the non-West Saxon dialects after Alfred's unification. Some Mercian texts continued to be written, however, and the influence of Mercian is apparent in some of the translations produced under Alfred's programme, many of which were produced by Mercian scholars. Other dialects certainly continued to be spoken, as
19690-531: The futhorc. A few letter pairs were used as digraphs , representing a single sound. Also used was the Tironian note ⟨⁊⟩ (a character similar to the digit 7) for the conjunction and . A common scribal abbreviation was a thorn with a stroke ⟨ꝥ⟩ , which was used for the pronoun þæt ( that ). Macrons over vowels were originally used not to mark long vowels (as in modern editions), but to indicate stress, or as abbreviations for
19869-475: The homosphere, which includes the troposphere, stratosphere, and mesosphere. Within these layers of the atmosphere , air can become saturated as a result of being cooled to its dew point or by having moisture added from an adjacent source. In the latter case, saturation occurs when the dew point is raised to the ambient air temperature. Adiabatic cooling occurs when one or more of three possible lifting agents – convective, cyclonic/frontal, or orographic – cause
20048-603: The inscriptions on the Franks Casket ) date to the early 8th century. The Old English Latin alphabet was introduced around the 8th century. With the unification of several of the Anglo-Saxon kingdoms (outside the Danelaw ) by Alfred the Great in the later 9th century, the language of government and literature became standardised around the West Saxon dialect (Early West Saxon). Alfred advocated education in English alongside Latin, and had many works translated into
20227-413: The lack of discipline among weather observers, and the poor quality of the instruments, led the early modern nation states to organise large observation networks. Thus, by the end of the 18th century, meteorologists had access to large quantities of reliable weather data. In 1832, an electromagnetic telegraph was created by Baron Schilling . The arrival of the electrical telegraph in 1837 afforded, for
20406-510: The lakes and the Nile. Hippocrates inquired into the effect of weather on health. Eudoxus claimed that bad weather followed four-year periods, according to Pliny. These early observations would form the basis for Aristotle 's Meteorology , written in 350 BC. Aristotle is considered the founder of meteorology. One of the most impressive achievements described in the Meteorology is
20585-439: The largest of all cloud genera, has the capacity to produce very heavy showers. Low stratus clouds usually produce only light precipitation, but this always occurs as the feature praecipitatio due to the fact this cloud genus lies too close to the ground to allow for the formation of virga. Incus is the most type-specific supplementary feature, seen only with cumulonimbus of the species capillatus. A cumulonimbus incus cloud top
20764-437: The late 16th century and first half of the 17th century a range of meteorological instruments were invented – the thermometer , barometer , hydrometer , as well as wind and rain gauges. In the 1650s natural philosophers started using these instruments to systematically record weather observations. Scientific academies established weather diaries and organised observational networks. In 1654, Ferdinando II de Medici established
20943-517: The latitudinal geographical zone . Each altitude level comprises two or three genus-types differentiated mainly by physical form. The standard levels and genus-types are summarised below in approximate descending order of the altitude at which each is normally based. Multi-level clouds with significant vertical extent are separately listed and summarized in approximate ascending order of instability or convective activity. High clouds form at altitudes of 3,000 to 7,600 m (10,000 to 25,000 ft) in
21122-449: The latter applied only to "strong" masculine nouns in the nominative and accusative cases; different plural endings were used in other instances. Old English nouns had grammatical gender , while modern English has only natural gender. Pronoun usage could reflect either natural or grammatical gender when those conflicted, as in the case of ƿīf , a neuter noun referring to a female person. In Old English's verbal compound constructions are
21301-439: The latter, upward-growing cumulus mediocris produces only isolated light showers, while downward growing nimbostratus is capable of heavier, more extensive precipitation. Towering vertical clouds have the greatest ability to produce intense precipitation events, but these tend to be localized unless organized along fast-moving cold fronts. Showers of moderate to heavy intensity can fall from cumulus congestus clouds. Cumulonimbus,
21480-550: The laws of physics, and more particularly in the latter half of the 20th century, the development of the computer (allowing for the automated solution of a great many modelling equations) that significant breakthroughs in weather forecasting were achieved. An important branch of weather forecasting is marine weather forecasting as it relates to maritime and coastal safety, in which weather effects also include atmospheric interactions with large bodies of water. Meteorological phenomena are observable weather events that are explained by
21659-443: The mechanical, self-emptying, tipping bucket rain gauge. In 1714, Gabriel Fahrenheit created a reliable scale for measuring temperature with a mercury-type thermometer . In 1742, Anders Celsius , a Swedish astronomer, proposed the "centigrade" temperature scale, the predecessor of the current Celsius scale. In 1783, the first hair hygrometer was demonstrated by Horace-Bénédict de Saussure . In 1802–1803, Luke Howard wrote On
21838-448: The mid-15th century and were respectively the rain gauge , the anemometer, and the hygrometer. Many attempts had been made prior to the 15th century to construct adequate equipment to measure the many atmospheric variables. Many were faulty in some way or were simply not reliable. Even Aristotle noted this in some of his work as the difficulty to measure the air. Sets of surface measurements are important data to meteorologists. They give
22017-428: The mid-5th century, and the first Old English literary works date from the mid-7th century. After the Norman Conquest of 1066, English was replaced for several centuries by Anglo-Norman (a type of French ) as the language of the upper classes. This is regarded as marking the end of the Old English era, since during the subsequent period the English language was heavily influenced by Anglo-Norman, developing into what
22196-656: The mid-altitude range and sometimes higher in the case of nimbostratus. These very large cumuliform and cumulonimbiform types have cloud bases in the same low- to mid-level range as the multi-level and moderate vertical types, but the tops nearly always extend into the high levels. Unlike less vertically developed clouds, they are required to be identified by their standard names or abbreviations in all aviation observations (METARS) and forecasts (TAFS) to warn pilots of possible severe weather and turbulence. Genus types are commonly divided into subtypes called species that indicate specific structural details which can vary according to
22375-456: The modern knight ( /naɪt/ ). The following table lists the Old English letters and digraphs together with the phonemes they represent, using the same notation as in the Phonology section above. After /n/ , /j/ was realized as [dʒ] and /ɣ/ was realized as [ɡ] . The spellings ⟨ncg⟩ , ⟨ngc⟩ and even ⟨ncgg⟩ were occasionally used instead of
22554-505: The naive reader would not assume that they are chronologically related. Each of these four dialects was associated with an independent kingdom on the islands. Of these, Northumbria south of the Tyne , and most of Mercia , were overrun by the Vikings during the 9th century. The portion of Mercia that was successfully defended, and all of Kent , were then integrated into Wessex under Alfred
22733-435: The name pannus (see section on supplementary features). These species are subdivisions of genus types that can occur in partly unstable air with limited convection . The species castellanus appears when a mostly stable stratocumuliform or cirriform layer becomes disturbed by localized areas of airmass instability, usually in the morning or afternoon. This results in the formation of embedded cumuliform buildups arising from
22912-620: The name volutus , a roll cloud that can occur ahead of a cumulonimbus formation. There are some volutus clouds that form as a consequence of interactions with specific geographical features rather than with a parent cloud. Perhaps the strangest geographically specific cloud of this type is the Morning Glory , a rolling cylindrical cloud that appears unpredictably over the Gulf of Carpentaria in Northern Australia . Associated with
23091-553: The night, with change being likely at one of these divisions. Applying the divisions and a principle of balance in the yearly weather, he came up with forecasts like that if a lot of rain falls in the winter, the spring is usually dry. Rules based on actions of animals are also present in his work, like that if a dog rolls on the ground, it is a sign of a storm. Shooting stars and the Moon were also considered significant. However, he made no attempt to explain these phenomena, referring only to
23270-511: The opposite effect. Rene Descartes 's Discourse on the Method (1637) typifies the beginning of the scientific revolution in meteorology. His scientific method had four principles: to never accept anything unless one clearly knew it to be true; to divide every difficult problem into small problems to tackle; to proceed from the simple to the complex, always seeking relationships; to be as complete and thorough as possible with no prejudice. In
23449-512: The past tense of the weak verbs, as in work and worked . Old English syntax is similar to that of modern English . Some differences are consequences of the greater level of nominal and verbal inflection, allowing freer word order . Old English was first written in runes , using the futhorc —a rune set derived from the Germanic 24-character elder futhark , extended by five more runes used to represent Anglo-Saxon vowel sounds and sometimes by several more additional characters. From around
23628-526: The pattern of atmospheric lows and highs . In 1959, the UK Meteorological Office received its first computer, a Ferranti Mercury . In the 1960s, the chaotic nature of the atmosphere was first observed and mathematically described by Edward Lorenz , founding the field of chaos theory . These advances have led to the current use of ensemble forecasting in most major forecasting centers, to take into account uncertainty arising from
23807-399: The physical forms and genera with which each is normally associated. The forms, genera, and species are listed from left to right in approximate ascending order of instability or convective activity. Of the non-convective stratiform group, high-level cirrostratus comprises two species. Cirrostratus nebulosus has a rather diffuse appearance lacking in structural detail. Cirrostratus fibratus
23986-482: The prefix alto- while high-level variants of these same two forms carry the prefix cirro- . In the case of stratocumuliform clouds, the prefix strato- is applied to the low-level genus type but is dropped from the mid- and high-level varients to avoid double-prefixing with alto- and cirro-. Genus types with sufficient vertical extent to occupy more than one level do not carry any altitude-related prefixes. They are classified formally as low- or mid-level depending on
24165-415: The prognostic fluid dynamics equations that govern atmospheric flow could be neglected, and a numerical calculation scheme that could be devised to allow predictions. Richardson envisioned a large auditorium of thousands of people performing the calculations. However, the sheer number of calculations required was too large to complete without electronic computers, and the size of the grid and time steps used in
24344-455: The purpose of satellite analysis. They are given below in approximate ascending order of instability or convective activity. Tropospheric clouds form in any of three levels (formerly called étages ) based on altitude range above the Earth's surface. The grouping of clouds into levels is commonly done for the purposes of cloud atlases , surface weather observations , and weather maps . The base-height range for each level varies depending on
24523-526: The rain as caused by clouds becoming too large for the air to hold, and that clouds became snow if the air was not warm enough to melt them, or hail if they met colder wind. Like his predecessors, Descartes's method was deductive, as meteorological instruments were not developed and extensively used yet. He introduced the Cartesian coordinate system to meteorology and stressed the importance of mathematics in natural science. His work established meteorology as
24702-417: The same type, one above the other), is sometimes found with cirrus of both the fibratus and uncinus species, and with altocumulus and stratocumulus of the species stratiformis and lenticularis. The variety undulatus (having a wavy undulating base) can occur with any clouds of the species stratiformis or lenticularis, and with altostratus. It is only rarely observed with stratus nebulosus. The variety lacunosus
24881-475: The science of meteorology. Meteorological phenomena are described and quantified by the variables of Earth's atmosphere: temperature, air pressure, water vapour , mass flow , and the variations and interactions of these variables, and how they change over time. Different spatial scales are used to describe and predict weather on local, regional, and global levels. Meteorology, climatology , atmospheric physics , and atmospheric chemistry are sub-disciplines of
25060-442: The scientific revolution in meteorology. Speculation on the cause of the flooding of the Nile ended when Eratosthenes , according to Proclus , stated that it was known that man had gone to the sources of the Nile and observed the rains, although interest in its implications continued. During the era of Roman Greece and Europe, scientific interest in meteorology waned. In the 1st century BC, most natural philosophers claimed that
25239-440: The seasons. He believed that fire and water opposed each other in the atmosphere, and when fire gained the upper hand, the result was summer, and when water did, it was winter. Democritus also wrote about the flooding of the Nile. He said that during the summer solstice, snow in northern parts of the world melted. This would cause vapors to form clouds, which would cause storms when driven to the Nile by northerly winds, thus filling
25418-597: The second oldest national meteorological service in the world (the Central Institution for Meteorology and Geodynamics (ZAMG) in Austria was founded in 1851 and is the oldest weather service in the world). The first daily weather forecasts made by FitzRoy's Office were published in The Times newspaper in 1860. The following year a system was introduced of hoisting storm warning cones at principal ports when
25597-422: The similarity in appearance between a mass of rock and cumulus heap cloud. Over time, the metaphoric usage of the word supplanted the Old English weolcan , which had been the literal term for clouds in general. The table that follows is very broad in scope like the cloud genera template upon which it is partly based. There are some variations in styles of nomenclature between the classification scheme used for
25776-579: The sky could unlock the key to weather forecasting. Lamarck had worked independently on cloud classification the same year and had come up with a different naming scheme that failed to make an impression even in his home country of France because it used unusually descriptive and informal French names and phrases for cloud types. His system of nomenclature included 12 categories of clouds, with such names as (translated from French) hazy clouds, dappled clouds, and broom-like clouds. By contrast, Howard used universally accepted Latin, which caught on quickly after it
25955-598: The species and variety level. Rather, they are either hydrometeors or special cloud types with their own Latin names that form in association with certain cloud genera, species, and varieties. Supplementary features, whether in the form of clouds or precipitation, are directly attached to the main genus-cloud. Accessory clouds, by contrast, are generally detached from the main cloud. One group of supplementary features are not actual cloud formations, but precipitation that falls when water droplets or ice crystals that make up visible clouds have grown too heavy to remain aloft. Virga
26134-452: The stability and windshear characteristics of the atmosphere at any given time and location. Despite this hierarchy, a particular species may be a subtype of more than one genus, especially if the genera are of the same physical form and are differentiated from each other mainly by altitude or level. There are a few species, each of which can be associated with genera of more than one physical form. The species types are grouped below according to
26313-473: The stratiformis species of altocumulus and stratocumulus. However, only two varieties are seen with altostratus and stratus nebulosus whose uniform structures prevent the formation of a perlucidus variety. Opacity-based varieties are not applied to high clouds because they are always translucent, or in the case of cirrus spissatus, always opaque. A second group describes the occasional arrangements of cloud structures into particular patterns that are discernible by
26492-609: The stratocumuliform genus or genera present at any given time. The species fractus shows variable instability because it can be a subdivision of genus-types of different physical forms that have different stability characteristics. This subtype can be in the form of ragged but mostly stable stratiform sheets (stratus fractus) or small ragged cumuliform heaps with somewhat greater instability (cumulus fractus). When clouds of this species are associated with precipitating cloud systems of considerable vertical and sometimes horizontal extent, they are also classified as accessory clouds under
26671-635: The stratosphere and mesosphere, clouds have common names for their main types. They may have the appearance of stratiform veils or sheets, cirriform wisps, or stratocumuliform bands or ripples. They are seen infrequently, mostly in the polar regions of Earth. Clouds have been observed in the atmospheres of other planets and moons in the Solar System and beyond. However, due to their different temperature characteristics, they are often composed of other substances such as methane , ammonia , and sulfuric acid , as well as water. Tropospheric clouds can have
26850-427: The telegraph and photography led to the creation of weather observing networks and the ability to track storms. Additionally, scientists began to use mathematical models to make predictions about the weather. The 20th century saw the development of radar and satellite technology, which greatly improved the ability to observe and track weather systems. In addition, meteorologists and atmospheric scientists started to create
27029-535: The term used before a standardization of Latin nomenclature brought about by the World Meteorological Organization during the 20th century. The best-known is cumulonimbus with mammatus , but the mamma feature is also seen occasionally with cirrus, cirrocumulus, altocumulus, altostratus, and stratocumulus. Meteorology Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with
27208-409: The theorized Brittonicisms do not become widespread until the late Middle English and Early Modern English periods, in addition to the fact that similar forms exist in other modern Germanic languages. Old English contained a certain number of loanwords from Latin , which was the scholarly and diplomatic lingua franca of Western Europe. It is sometimes possible to give approximate dates for
27387-564: The time still lacked the letters ⟨j⟩ and ⟨w⟩ , and there was no ⟨v⟩ as distinct from ⟨u⟩ ; moreover native Old English spellings did not use ⟨k⟩ , ⟨q⟩ or ⟨z⟩ . The remaining 20 Latin letters were supplemented by four more: ⟨ æ ⟩ ( æsc , modern ash ) and ⟨ð⟩ ( ðæt , now called eth or edh), which were modified Latin letters, and thorn ⟨þ⟩ and wynn ⟨ƿ⟩ , which are borrowings from
27566-487: The tropics. As with high clouds, the main genus types are easily identified by the human eye, but distinguishing between them using satellite photography alone is not possible. When the supporting data of human observations are not available, these clouds are usually collectively identified as middle-type on satellite images. Low clouds are found from near the surface up to 2,000 m (6,500 ft). Genus types in this level either have no prefix or carry one that refers to
27745-486: The troposphere (strict Latin except for surface-based aerosols) and the higher levels of the homosphere (common terms, some informally derived from Latin). However, the schemes presented here share a cross-classification of physical forms and altitude levels to derive the 10 tropospheric genera, the fog and mist that forms at surface level, and several additional major types above the troposphere. The cumulus genus includes four species that indicate vertical size which can affect
27924-462: The troposphere during the late 19th century eventually led to the creation of separate classification schemes that reverted to the use of descriptive common names and phrases that somewhat recalled Lamarck's methods of classification. These very high clouds, although classified by these different methods, are nevertheless broadly similar to some cloud forms identified in the troposphere with Latin names. Terrestrial clouds can be found throughout most of
28103-421: The troposphere is based on a hierarchy of categories with physical forms and altitude levels at the top. These are cross-classified into a total of ten genus types, most of which can be divided into species and further subdivided into varieties which are at the bottom of the hierarchy. Clouds in the troposphere assume five physical forms based on structure and process of formation. These forms are commonly used for
28282-484: The troposphere when stable air is forced aloft at weather fronts and around centers of low pressure by a process called convergence . Warm fronts associated with extratropical cyclones tend to generate mostly cirriform and stratiform clouds over a wide area unless the approaching warm airmass is unstable, in which case cumulus congestus or cumulonimbus clouds are usually embedded in the main precipitating cloud layer. Cold fronts are usually faster moving and generate
28461-402: The troposphere where these agents are most active. However, water vapor that has been lifted to the top of troposphere can be carried even higher by gravity waves where further condensation can result in the formation of clouds in the stratosphere and mesosphere. Along with adiabatic cooling that requires a lifting agent, three major nonadiabatic mechanisms exist for lowering the temperature of
28640-668: The troposphere, the atmospheric layer closest to Earth's surface, have Latin names because of the universal adoption of Luke Howard 's nomenclature that was formally proposed in 1802. It became the basis of a modern international system that divides clouds into five physical forms which can be further divided or classified into altitude levels to derive ten basic genera . The main representative cloud types for each of these forms are stratiform , cumuliform , stratocumuliform , cumulonimbiform , and cirriform . Low-level clouds do not have any altitude-related prefixes. However mid-level stratiform and stratocumuliform types are given
28819-528: The unique, local, or broad effects within those subclasses. Old English Old English ( Englisċ or Ænglisc , pronounced [ˈeŋɡliʃ] ), or Anglo-Saxon , was the earliest recorded form of the English language , spoken in England and southern and eastern Scotland in the early Middle Ages . It developed from the languages brought to Great Britain by Anglo-Saxon settlers in
28998-404: The usual ⟨ng⟩ . The addition of ⟨c⟩ to ⟨g⟩ in spellings such as ⟨cynincg⟩ and ⟨cyningc⟩ for ⟨cyning⟩ may have been a means of showing that the word was pronounced with a stop rather than a fricative; spellings with just ⟨nc⟩ such as ⟨cyninc⟩ are also found. To disambiguate,
29177-590: The value of his work is in preserving earlier speculation, much like Seneca's work. From 400 to 1100, scientific learning in Europe was preserved by the clergy. Isidore of Seville devoted a considerable attention to meteorology in Etymologiae , De ordine creaturum and De natura rerum . Bede the Venerable was the first Englishman to write about the weather in De Natura Rerum in 703. The work
29356-423: The word was so nearly the same in the two languages that only the endings would put obstacles in the way of mutual understanding. In the mixed population which existed in the Danelaw, these endings must have led to much confusion, tending gradually to become obscured and finally lost. This blending of peoples and languages resulted in "simplifying English grammar". The inventory of Early West Saxon surface phones
29535-417: Was a summary of then extant classical sources. However, Aristotle's works were largely lost until the twelfth century, including Meteorologica . Isidore and Bede were scientifically minded, but they adhered to the letter of Scripture . Islamic civilization translated many ancient works into Arabic which were transmitted and translated in western Europe to Latin. In the 9th century, Al-Dinawari wrote
29714-443: Was an allophone of short /ɑ/ which occurred in stressed syllables before nasal consonants (/m/ and /n/). It was variously spelled either ⟨a⟩ or ⟨o⟩. The Anglian dialects also had the mid front rounded vowel /ø(ː)/ , spelled ⟨œ⟩, which had emerged from i-umlaut of /o(ː)/ . In West Saxon and Kentish, it had already merged with /e(ː)/ before the first written prose. Other dialects had different systems of diphthongs. For example,
29893-439: Was based on the West Saxon dialect , away from the main area of Scandinavian influence; the impact of Norse may have been greater in the eastern and northern dialects. Certainly in Middle English texts, which are more often based on eastern dialects, a strong Norse influence becomes apparent. Modern English contains many, often everyday, words that were borrowed from Old Norse, and the grammatical simplification that occurred after
30072-472: Was considered a subset of astronomy. He gave several astrological weather predictions. He constructed a map of the world divided into climatic zones by their illumination, in which the length of the Summer solstice increased by half an hour per zone between the equator and the Arctic. Ptolemy wrote on the atmospheric refraction of light in the context of astronomical observations. In 25 AD, Pomponius Mela ,
30251-481: Was either /ʃ/ or possibly /ʃː/ when the preceding vowel was short. Doubled consonants are geminated ; the geminate fricatives ⟨ff⟩ , ⟨ss⟩ and ⟨ðð⟩ / ⟨þþ⟩ / ⟨ðþ⟩ / ⟨þð⟩ are always voiceless [ff] , [ss] , [θθ] . The corpus of Old English literature is small but still significant, with some 400 surviving manuscripts. The pagan and Christian streams mingle in Old English, one of
30430-616: Was followed by such writers as the prolific Ælfric of Eynsham ("the Grammarian"). This form of the language is known as the " Winchester standard", or more commonly as Late West Saxon. It is considered to represent the "classical" form of Old English. It retained its position of prestige until the time of the Norman Conquest, after which English ceased for a time to be of importance as a literary language. The history of Old English can be subdivided into: The Old English period
30609-428: Was less important than appeal to the classics and authority in medieval thought. In the thirteenth century, Roger Bacon advocated experimentation and the mathematical approach. In his Opus majus , he followed Aristotle's theory on the atmosphere being composed of water, air, and fire, supplemented by optics and geometric proofs. He noted that Ptolemy's climatic zones had to be adjusted for topography . St. Albert
30788-562: Was made between long and short vowels in the originals. (In some older editions an acute accent mark was used for consistency with Old Norse conventions.) Additionally, modern editions often distinguish between velar and palatal ⟨c⟩ and ⟨g⟩ by placing dots above the palatals: ⟨ċ⟩ , ⟨ġ⟩ . The letter wynn ⟨ƿ⟩ is usually replaced with ⟨w⟩ , but ⟨æ⟩ , ⟨ð⟩ and ⟨þ⟩ are normally retained (except when ⟨ð⟩
30967-406: Was not generally accepted for centuries. A theory to explain summer hail was first proposed by Anaxagoras . He observed that air temperature decreased with increasing height and that clouds contain moisture. He also noted that heat caused objects to rise, and therefore the heat on a summer day would drive clouds to an altitude where the moisture would freeze. Empedocles theorized on the change of
31146-504: Was published in 1803. As a sign of the popularity of the naming scheme, German dramatist and poet Johann Wolfgang von Goethe composed four poems about clouds, dedicating them to Howard. An elaboration of Howard's system was eventually formally adopted by the International Meteorological Conference in 1891. This system covered only the tropospheric cloud types. However, the discovery of clouds above
31325-411: Was spoken and Danish law applied. Old English literacy developed after Christianisation in the late 7th century. The oldest surviving work of Old English literature is Cædmon's Hymn , which was composed between 658 and 680 but not written down until the early 8th century. There is a limited corpus of runic inscriptions from the 5th to 7th centuries, but the oldest coherent runic texts (notably
31504-603: Was subject to strong Old Norse influence due to Scandinavian rule and settlement beginning in the 9th century. Old English is one of the West Germanic languages , and its closest relatives are Old Frisian and Old Saxon . Like other old Germanic languages, it is very different from Modern English and Modern Scots, and largely incomprehensible for Modern English or Modern Scots speakers without study. Within Old English grammar nouns, adjectives, pronouns and verbs have many inflectional endings and forms, and word order
31683-425: Was substantive, pervasive, and of a democratic character. Old Norse and Old English resembled each other closely like cousins, and with some words in common, speakers roughly understood each other; in time the inflections melted away and the analytic pattern emerged. It is most important to recognize that in many words the English and Scandinavian language differed chiefly in their inflectional elements. The body of
31862-399: Was the first work to challenge fundamental aspects of Aristotelian theory. Cardano maintained that there were only three basic elements- earth, air, and water. He discounted fire because it needed material to spread and produced nothing. Cardano thought there were two kinds of air: free air and enclosed air. The former destroyed inanimate things and preserved animate things, while the latter had
32041-536: Was written by George Hadley . In 1743, when Benjamin Franklin was prevented from seeing a lunar eclipse by a hurricane , he decided that cyclones move in a contrary manner to the winds at their periphery. Understanding the kinematics of how exactly the rotation of the Earth affects airflow was partial at first. Gaspard-Gustave Coriolis published a paper in 1835 on the energy yield of machines with rotating parts, such as waterwheels. In 1856, William Ferrel proposed
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