Misplaced Pages

#231768

86-502: The Beaufort scale ( / ˈ b oʊ f ər t / BOH -fərt ) is an empirical measure that relates wind speed to observed conditions at sea or on land. Its full name is the Beaufort wind force scale . The scale that carries Beaufort's name had a long and complex evolution from the previous work of others (including Daniel Defoe the century before). In the 18th century, naval officers made regular weather observations, but there

172-574: A severe tropical storm . Once the system's maximum sustained winds reach wind speeds of 64 knots (74 mph; 119 km/h), the JMA will designate the tropical cyclone as a typhoon —the highest category on its scale. Since 2009 the Hong Kong Observatory has divided typhoons into three different classifications: typhoon , severe typhoon and super typhoon . A typhoon has wind speed of 64–79 knots (73–91 mph; 118–149 km/h),

258-620: A "strong wind warning" would have been referred to as a "small craft warning" by Environment Canada, similar to US terminology. (Canada and the USA have the Great Lakes in common.) Beaufort's name was also attached to the Beaufort scale for weather reporting: In this scale the weather designations could be combined, and reported, for example, as "s.c." for snow and detached cloud or "g.r.q." for dark, rain and squally. Empirical There

344-409: A bacterium is a form of experimentation while studying planetary orbits through a telescope belongs to mere observation. In these cases, the mutated DNA was actively produced by the biologist while the planetary orbits are independent of the astronomer observing them. Applied to the history of science, it is sometimes held that ancient science is mainly observational while the emphasis on experimentation

430-478: A belief. So experience may be needed to acquire the relevant concepts in the example above, but once these concepts are possessed, no further experience providing empirical evidence is needed to know that the proposition is true, which is why it is considered to be justified a priori . In its strictest sense, empiricism is the view that all knowledge is based on experience or that all epistemic justification arises from empirical evidence. This stands in contrast to

516-489: A common understanding of measurement. In the scientific context, the term semi-empirical is used for qualifying theoretical methods that use, in part, basic axioms or postulated scientific laws and experimental results. Such methods are opposed to theoretical ab initio methods, which are purely deductive and based on first principles . Typical examples of both ab initio and semi-empirical methods can be found in computational chemistry . Typhoon A typhoon

602-606: A general definition of "intervention" applying to all cases, which is why it is sometimes outright rejected. Empirical evidence is required for a hypothesis to gain acceptance in the scientific community . Normally, this validation is achieved by the scientific method of forming a hypothesis, experimental design , peer review , reproduction of results , conference presentation, and journal publication . This requires rigorous communication of hypothesis (usually expressed in mathematics), experimental constraints and controls (expressed in terms of standard experimental apparatus), and

688-453: A low level feature with sufficient vorticity and convergence is required to begin tropical cyclogenesis. About 85 to 90 percent of Pacific typhoons form within the monsoon trough . Even with perfect upper-level conditions and the required atmospheric instability, the lack of a surface focus will prevent the development of organized convection and a surface low. Vertical wind shear of less than 10 m/s (20 kn, 33 ft/s) between

774-432: A posteriori knowledge or empirical knowledge , knowledge whose justification or falsification depends on experience or experiment. A priori knowledge, on the other hand, is seen either as innate or as justified by rational intuition and therefore as not dependent on empirical evidence. Rationalism fully accepts that there is knowledge a priori , which is either outright rejected by empiricism or accepted only in

860-407: A proposition, the subject has to be able to entertain this proposition, i.e. possess the relevant concepts. For example, experience is necessary to entertain the proposition "if something is red all over then it is not green all over" because the terms "red" and "green" have to be acquired this way. But the sense of dependence most relevant to empirical evidence concerns the status of justification of

946-540: A restricted way as knowledge of relations between our concepts but not as pertaining to the external world. Scientific evidence is closely related to empirical evidence but not all forms of empirical evidence meet the standards dictated by scientific methods . Sources of empirical evidence are sometimes divided into observation and experimentation , the difference being that only experimentation involves manipulation or intervention: phenomena are actively created instead of being passively observed. The concept of evidence

SECTION 10

#1732771786232

1032-513: A severe typhoon has winds of at least 80 knots (92 mph; 150 km/h), and a super typhoon has winds of at least 100 knots (120 mph; 190 km/h). The United States ' Joint Typhoon Warning Center (JTWC) unofficially classifies typhoons with wind speeds of at least 130 knots (67 m/s; 150 mph; 241 km/h)—the equivalent of a strong Category 4 storm in the Saffir-Simpson scale —as super typhoons . However,

1118-443: A that-clause, like "that something is burning". But it runs counter to the common practice of treating non-propositional sense-experiences, like bodily pains, as evidence. Its defenders sometimes combine it with the view that evidence has to be factive, i.e. that only attitudes towards true propositions constitute evidence. In this view, there is no misleading evidence. The olfactory experience of smoke would count as evidence if it

1204-780: A tropical cyclone). A set of red warning flags (daylight) and red warning lights (night time) is displayed at shore establishments which coincide with the various levels of warning. In Canada, maritime winds forecast to be in the range of 6 to 7 are designated as "strong"; 8 to 9 "gale force"; 10 to 11 "storm force"; 12 "hurricane force". Appropriate wind warnings are issued by Environment Canada's Meteorological Service of Canada: strong wind warning, gale (force wind) warning, storm (force wind) warning and hurricane-force wind warning. These designations were standardised nationally in 2008, whereas "light wind" can refer to 0 to 12 or 0 to 15 knots and "moderate wind" 12 to 19 or 16 to 19 knots, depending on regional custom, definition or practice. Prior to 2008,

1290-588: Is a tropical cyclone that develops between 180° and 100°E in the Northern Hemisphere and which produces sustained hurricane-force winds of at least 119 km/h (74 mph). This region is referred to as the Northwestern Pacific Basin , accounting for almost one third of the world's tropical cyclones. The term hurricane refers to a tropical cyclone (again with sustained winds of at least 119 km/h (74 mph)) in

1376-487: Is also widely used in the Netherlands, Germany, Greece, China, Taiwan, Hong Kong, Malta, and Macau, although with some differences between them. Taiwan uses the Beaufort scale with the extension to 17 noted above. China also switched to this extended version without prior notice on the morning of 15 May 2006, and the extended scale was immediately put to use for Typhoon Chanchu . Hong Kong and Macau retain force 12 as

1462-400: Is an important advocate of the position that theory-ladenness concerning scientific paradigms plays a central role in science. A thing is evidence for a proposition if it epistemically supports this proposition or indicates that the supported proposition is true. Evidence is empirical if it is constituted by or accessible to sensory experience. There are various competing theories about

1548-523: Is considered the minimum to maintain the special mesocyclone that is the tropical cyclone. These warm waters are needed to maintain the warm core that fuels tropical systems. A minimum distance of 500 km (300 mi) from the equator is normally needed for tropical cyclogenesis. Whether it be a depression in the Intertropical Convergence Zone (ITCZ) or monsoon trough , a broad surface front , or an outflow boundary ,

1634-677: Is either Chinese or Persian-Hindustani origin. Typhoon may trace to 風癡 (meaning "winds which long last"), first attested in 1124 in China. It was pronounced as [hɔŋ tsʰi] in Min Chinese at the time, but later evolved to [hɔŋ tʰai]. New characters 風颱 were created to match the sound, no later than 1566. The word was introduced to Mandarin Chinese in the inverted Mandarin order 颱風 [tʰaɪ fɤŋ] , later picked up by foreign sailors to appear as typhoon. The usage of 颱風

1720-604: Is general consensus that everyday objects like books or houses are observable since they are accessible via unaided perception, but disagreement starts for objects that are only accessible through aided perception. This includes using telescopes to study distant galaxies, microscopes to study bacteria or using cloud chambers to study positrons. So the question is whether distant galaxies, bacteria or positrons should be regarded as observable or merely theoretical objects. Some even hold that any measurement process of an entity should be considered an observation of this entity. In this sense,

1806-473: Is given more weight, although science done poorly is also subject to such biases, as in the example of p -hacking . In the philosophy of science, it is sometimes held that there are two sources of empirical evidence: observation and experimentation . The idea behind this distinction is that only experimentation involves manipulation or intervention: phenomena are actively created instead of being passively observed. For example, inserting viral DNA into

SECTION 20

#1732771786232

1892-737: Is in Japan , with other tropical cyclone warning centres for the northwest Pacific in Hawaii (the Joint Typhoon Warning Center ), the Philippines , and Hong Kong . Although the RSMC names each system, the main name list itself is coordinated among 18 countries that have territories threatened by typhoons each year. Within most of the northwestern Pacific, there are no official typhoon seasons as tropical cyclones form throughout

1978-482: Is legitimate in other contexts. For example, anecdotal evidence from a friend about how to treat a certain disease constitutes empirical evidence that this treatment works but would not be considered scientific evidence. Others have argued that the traditional empiricist definition of empirical evidence as perceptual evidence is too narrow for much of scientific practice, which uses evidence from various kinds of non-perceptual equipment. Central to scientific evidence

2064-492: Is no general agreement on how the terms evidence and empirical are to be defined. Often different fields work with quite different conceptions. In epistemology, evidence is what justifies beliefs or what determines whether holding a certain belief is rational . This is only possible if the evidence is possessed by the person, which has prompted various epistemologists to conceive evidence as private mental states like experiences or other beliefs. In philosophy of science , on

2150-445: Is of central importance in epistemology and in philosophy of science but plays different roles in these two fields. In epistemology, evidence is what justifies beliefs or what determines whether holding a certain doxastic attitude is rational . For example, the olfactory experience of smelling smoke justifies or makes it rational to hold the belief that something is burning. It is usually held that for justification to work,

2236-440: Is only present in modern science and responsible for the scientific revolution . This is sometimes phrased through the expression that modern science actively "puts questions to nature". This distinction also underlies the categorization of sciences into experimental sciences, like physics, and observational sciences, like astronomy. While the distinction is relatively intuitive in paradigmatic cases, it has proven difficult to give

2322-421: Is still sometimes used in weather forecasts for shipping and the severe weather warnings given to the public. Wind speed on the Beaufort scale is based on the empirical relationship : where v is the equivalent wind speed at 10 metres above the sea surface and B is Beaufort scale number. For example, B = 9.5 is related to 24.5 m/s which is equal to the lower limit of "10 Beaufort". Using this formula

2408-447: Is that it was arrived at by following scientific method in the context of some scientific theory . But people rely on various forms of empirical evidence in their everyday lives that have not been obtained this way and therefore do not qualify as scientific evidence. One problem with non-scientific evidence is that it is less reliable, for example, due to cognitive biases like the anchoring effect , in which information obtained earlier

2494-447: Is the term used for a tropical system that has wind speeds not exceeding 33 knots (38 mph; 61 km/h). A tropical depression is upgraded to a tropical storm should its sustained wind speeds exceed 34 knots (39 mph; 63 km/h). Tropical storms also receive official names from RSMC Tokyo. Should the storm intensify further and reach sustained wind speeds of 48 knots (55 mph; 89 km/h) then it will be classified as

2580-504: Is to account for the justification of knowledge pertaining to fields like mathematics and logic, for example, that 3 is a prime number or that modus ponens is a valid form of deduction. The difficulty is due to the fact that there seems to be no good candidate of empirical evidence that could justify these beliefs. Such cases have prompted empiricists to allow for certain forms of knowledge a priori, for example, concerning tautologies or relations between our concepts. These concessions preserve

2666-403: Is to hold that it is a mistake to identify the empirical with what is observable or sensible. Instead, it has been suggested that empirical evidence can include unobservable entities as long as they are detectable through suitable measurements. A problem with this approach is that it is rather far from the original meaning of "empirical", which contains the reference to experience. Knowledge or

Beaufort scale - Misplaced Pages Continue

2752-441: Is usually seen as excluding purely intellectual experiences, like rational insights or intuitions used to justify basic logical or mathematical principles. The terms empirical and observable are closely related and sometimes used as synonyms. There is an active debate in contemporary philosophy of science as to what should be regarded as observable or empirical in contrast to unobservable or merely theoretical objects. There

2838-404: Is usually understood as what is observable, in contrast to unobservable or theoretical objects. It is generally accepted that unaided perception constitutes observation, but it is disputed to what extent objects accessible only to aided perception, like bacteria seen through a microscope or positrons detected in a cloud chamber, should be regarded as observable. Empirical evidence is essential to

2924-418: Is why it is more common to hold that all kinds of mental states, including stored but currently unconscious beliefs, can act as evidence. Various of the roles played by evidence in reasoning, for example, in explanatory, probabilistic and deductive reasoning, suggest that evidence has to be propositional in nature, i.e. that it is correctly expressed by propositional attitude verbs like "believe" together with

3010-416: The justification of a belief is said to be a posteriori if it is based on empirical evidence. A posteriori refers to what depends on experience (what comes after experience), in contrast to a priori , which stands for what is independent of experience (what comes before experience). For example, the proposition that "all bachelors are unmarried" is knowable a priori since its truth only depends on

3096-427: The rationalist view, which holds that some knowledge is independent of experience, either because it is innate or because it is justified by reason or rational reflection alone. Expressed through the distinction between knowledge a priori and a posteriori from the previous section, rationalism affirms that there is knowledge a priori, which is denied by empiricism in this strict form. One difficulty for empiricists

3182-544: The 1660s and 1670s. The highest reliably-estimated maximum sustained winds on record for a typhoon was that of Typhoon Haiyan at 314 km/h (195 mph) shortly before its landfall in the central Philippines on November 8, 2013. The most intense storm based on minimum pressure was Typhoon Tip in the northwestern Pacific Ocean in 1979, which reached a minimum pressure of 870 hectopascals (26 inHg) and maximum sustained wind speeds of 165 knots (85 m/s, 190 mph, 310 km/h). The deadliest typhoon of

3268-779: The 20th century was Typhoon Nina , which killed nearly 100,000 in China in 1975 due to a flood that caused 12 reservoirs to fail. After Typhoon Morakot landed in Taiwan at midnight on August 8, 2009, almost the entire southern region of Taiwan ( Chiayi County / Chiayi City , Tainan County / Tainan City (now merged as Tainan), Kaohsiung County / Kaohsiung City (now merged as Kaohsiung), and Pingtung County ) and parts of Taitung County and Nantou County were flooded by record-breaking heavy rain. The rainfall in Pingtung County reached 2,327 millimeters (91.6 in), breaking all rainfall records of any single place in Taiwan induced by

3354-628: The Ancient Greek mythological creature Typhôn . In French typhon was attested as storm in 1504. Portuguese traveler Fernão Mendes Pinto referred to a tufão in his memoir published in 1614. The earliest form in English was "touffon" (1588), later as touffon, tuffon, tufon, tuffin, tuffoon, tayfun, tiffoon, typhawn. A tropical depression is the lowest category that the Japan Meteorological Agency uses and

3440-431: The Beaufort scale number, followed by a description, wind speed, wave height, sea conditions, land conditions, photo of the sea, and the associated warning flag. The Beaufort scale is neither an exact nor an objective scale; it was based on visual and subjective observation of a ship and of the sea. The corresponding integral wind speeds were determined later, but conversions have not been made official. The Beaufort scale

3526-460: The English word typhoon traced to the Cantonese pronunciation of 颱風 [tʰɔi fuŋ] (correspond to Mandarin [tʰaɪ fɤŋ] ), in turn the Cantonese word traced to Arabic. This claim contradicts the fact that the Cantonese term for typhoon was 風舊 [fuŋ kɐu] before the national promotion of 颱風 . 風舊 (meaning "winds which long last") was first attested in 280, being

Beaufort scale - Misplaced Pages Continue

3612-543: The Philippines, the most active season since 1945 for tropical cyclone strikes was 1993 , when nineteen tropical cyclones moved through the country. There was only one tropical cyclone that moved through the Philippines in 1958 . The 2004 Pacific typhoon season was the busiest for Okinawa since 1957. Within Guangdong in southern China, during the past thousand years, the most active decades for typhoon strikes were

3698-596: The United States who have territories directly affected by typhoons. The submitted names are arranged into a list, the names on the list will be used from up to down, from left to right. When all names on the list are used, it will start again from the left-top corner. When a typhoon causes damage in a region, the affected region can request for retiring the name in the next session of the ESCAP/WMO Typhoon Committee. A new name will be decided by

3784-586: The beginning of June through to the end of November, with an average of four to six typhoons hitting the country annually. According to the statistics of the Joint Typhoon Warning Center, from 1950 to 2022, the Northwest Pacific generated an average of 26.5 named tropical cyclones each year, of which an average of 16.6 reached typhoon standard or above as defined by the Joint Typhoon Warning Center. The etymology of typhoon

3870-459: The brunt of the landfalls, with China and Japan being less often impacted. However, some of the deadliest typhoons in history have struck China. Southern China has the longest record of typhoon impacts for the region, with a thousand-year sample via documents within their archives. Taiwan has received the wettest known typhoon on record for the northwest Pacific tropical cyclone basins . However, Vietnam recognises its typhoon season as lasting from

3956-616: The coastline, and the Irish Sea or part thereof: "Gale Warnings" are issued if winds of Beaufort force 8 are expected; "Strong Gale Warnings" are issued if winds of Beaufort force 9 or frequent gusts of at least 52 knots are expected.; "Storm Force Warnings" are issued if Beaufort force 10 or frequent gusts of at least 61 knots are expected; "Violent Storm Force Warnings" are issued if Beaufort force 11 or frequent gusts of at least 69 knots are expected; "Hurricane Force Warnings" are issued if winds of greater than 64 knots are expected. This scale

4042-480: The date line from the central Pacific retain their original name, but the designation of hurricane becomes typhoon. The most active Western Pacific typhoon season was in 1964 , when 39 storms of tropical storm strength formed. Only 15 seasons had 30 or more storms developing since reliable records began. The least activity seen in the northwest Pacific Ocean was during the 2010 Pacific typhoon season , when only 14 tropical storms and seven typhoons formed. In

4128-689: The descriptions were changed to how the sea, not the sails, behaved and extended to land observations. Anemometer rotations to scale numbers were standardised only in 1923. George Simpson , CBE (later Sir George Simpson), director of the UK Meteorological Office, was responsible for this and for the addition of the land-based descriptors. The measures were slightly altered some decades later to improve its utility for meteorologists . Nowadays, meteorologists typically express wind speed in kilometres or miles per hour or, for maritime and aviation purposes, knots , but Beaufort scale terminology

4214-484: The evidence has to be possessed by the believer. The most straightforward way to account for this type of evidence possession is to hold that evidence consists of the private mental states possessed by the believer. Some philosophers restrict evidence even further, for example, to only conscious, propositional or factive mental states. Restricting evidence to conscious mental states has the implausible consequence that many simple everyday beliefs would be unjustified. This

4300-402: The exact definition of the terms evidence and empirical . Different fields, like epistemology, the sciences or legal systems, often associate different concepts with these terms. An important distinction among theories of evidence is whether they identify evidence with private mental states or with public physical objects. Concerning the term empirical , there is a dispute about where to draw

4386-457: The existence of metaphysical knowledge, while rationalists seek justification for metaphysical claims in metaphysical intuitions. Scientific evidence is closely related to empirical evidence. Some theorists, like Carlos Santana, have argued that there is a sense in which not all empirical evidence constitutes scientific evidence. One reason for this is that the standards or criteria that scientists apply to evidence exclude certain evidence that

SECTION 50

#1732771786232

4472-402: The fact that the available evidence often provides equal support to either theory and therefore cannot arbitrate between them. Theory-ladenness refers to the idea that evidence already includes theoretical assumptions. These assumptions can hinder it from acting as neutral arbiter. It can also lead to a lack of shared evidence if different scientists do not share these assumptions. Thomas Kuhn

4558-539: The highest winds in hurricanes would be 23 in the scale. F1 tornadoes on the Fujita scale and T2 TORRO scale also begin roughly at the end of level 12 of the Beaufort scale, but are independent scales, although the TORRO scale wind values are based on the 3/2 power law relating wind velocity to Beaufort force. Wave heights in the scale are for conditions in the open ocean, not along the shore. The leftmost column gives

4644-471: The interior of the Sun is observable since neutrinos originating there can be detected. The difficulty with this debate is that there is a continuity of cases going from looking at something with the naked eye, through a window, through a pair of glasses, through a microscope, etc. Because of this continuity, drawing the line between any two adjacent cases seems to be arbitrary. One way to avoid these difficulties

4730-427: The line between observable or empirical objects in contrast to unobservable or merely theoretical objects. The traditional view proposes that evidence is empirical if it is constituted by or accessible to sensory experience. This involves experiences arising from the stimulation of the sense organs, like visual or auditory experiences, but the term is often used in a wider sense including memories and introspection. It

4816-433: The lower to middle levels of the troposphere , enough Coriolis force to develop a low pressure center, a pre-existing low level focus or disturbance, and low vertical wind shear. While these conditions are necessary for tropical cyclone formation, they do not guarantee that a tropical cyclone will form. Normally, an ocean temperature of 26.5 °C (79.7 °F) spanning through a depth of at least 50 metres (160 ft)

4902-627: The main ship of the Royal Navy , from "just sufficient to give steerage" to "that which no canvas sails could withstand". The scale was made a standard for ship's log entries on Royal Navy vessels in the late 1830s and, in 1853, the Beaufort scale was accepted as generally applicable at the First International Meteorological Conference in Brussels . In 1916, to accommodate the growth of steam power,

4988-447: The majority of storms form between June and November, a few storms may occur between December and May (although tropical cyclone formation is very rare during that time). On average, the northwestern Pacific features the most numerous and intense tropical cyclones globally. Like other basins, they are steered by the subtropical ridge towards the west or northwest, with some systems recurving near and east of Japan . The Philippines receive

5074-525: The maximum sustained wind speed measurements that the JTWC uses are based on a 1-minute averaging period, akin to the U.S.'s National Hurricane Center and Central Pacific Hurricane Center . As a result, the JTWC's wind reports are higher than JMA's measurements, as the latter is based on a 10-minute averaging interval. There are six main requirements for tropical cyclogenesis: sufficiently warm sea surface temperatures, atmospheric instability, high humidity in

5160-410: The maximum. In the United States of America, winds of force 6 or 7 result in the issuance of a small craft advisory , with force 8 or 9 winds bringing about a gale warning , force 10 or 11 a storm warning ("a tropical storm warning " being issued instead of the latter two if the winds relate to a tropical cyclone ), and force 12 a hurricane-force wind warning (or hurricane warning if related to

5246-422: The meanings of the words used in the expression. The proposition "some bachelors are happy", on the other hand, is only knowable a posteriori since it depends on experience of the world as its justifier. Immanuel Kant held that the difference between a posteriori and a priori is tantamount to the distinction between empirical and non-empirical knowledge. Two central questions for this distinction concern

SECTION 60

#1732771786232

5332-516: The most active on Earth. Pacific typhoons have formed year-round, with peak months from August to October. The peak months correspond to that of the Atlantic hurricane seasons . Along with a high storm frequency, this basin also features the most globally intense storms on record. One of the most recent busy seasons was 2013 . Tropical cyclones form in any month of the year across the northwest Pacific Ocean and concentrate around June and November in

5418-423: The north central and northeast Pacific, and the north Atlantic. In all of the preceding regions, weaker tropical cyclones are called tropical storms . For organizational purposes, the northern Pacific Ocean is divided into three regions: the eastern (North America to 140°W ), central (140°W to 180°), and western (180° to 100°E). The Regional Specialized Meteorological Center (RSMC) for tropical cyclone forecasts

5504-567: The northern Indian Ocean. The area just northeast of the Philippines is the most active place on Earth for tropical cyclones to exist. Across the Philippines themselves, activity reaches a minimum in February, before increasing steadily through June and spiking from July through October, with September being the most active month for tropical cyclones across the archipelago . Activity falls off significantly in November, although Typhoon Haiyan ,

5590-474: The ocean surface and the tropopause is required for tropical cyclone development. Typically with Pacific typhoons, there are two jets of outflow : one to the north ahead of an upper trough in the westerlies , and a second towards the equator. In general, the westerly wind increases associated with the Madden–Julian oscillation lead to increased tropical cyclogenesis in all tropical cyclone basins . As

5676-552: The oldest Chinese term for typhoon. Not one Chinese historical record links 颱風 to an Arabic or foreign origin. On the other hand, Chinese records consistently assert foreigners refer typhoon as "black wind". "Black wind" eventually enters the vocabulary of Jin Chinese as 黑老風 [xəʔ lo fəŋ] . Alternatively, some dictionaries propose that typhoon derived from (طوفان) tūfān , meaning storm in Persian and Hindustani . The root of (طوفان) tūfān possibly traces to

5762-419: The oscillation propagates from west to east, it leads to an eastward march in tropical cyclogenesis with time during that hemisphere's summer season. On average, twice per year twin tropical cyclones will form in the western Pacific Ocean, near the 5th parallel north and the 5th parallel south , along the same meridian, or line of longitude. There is an inverse relationship between tropical cyclone activity in

5848-438: The other hand, evidence is understood as that which confirms or disconfirms scientific hypotheses and arbitrates between competing theories. For this role, evidence must be public and uncontroversial, like observable physical objects or events and unlike private mental states, so that evidence may foster scientific consensus . The term empirical comes from Greek ἐμπειρία empeiría , i.e. 'experience'. In this context, it

5934-434: The region whose name was retired. Unlike tropical cyclones in other parts of the world, typhoons are not named after people. Instead, they generally refer to animals, flowers, astrological signs, and a few personal names. However, Philippines (PAGASA) retains its own naming list, which consists of both human names and other objects. Japan and some other East Asian countries also assign numbers to typhoons. Storms that cross

6020-505: The relevant sense of "experience" and of "dependence". The paradigmatic justification of knowledge a posteriori consists in sensory experience, but other mental phenomena, like memory or introspection, are also usually included in it. But purely intellectual experiences, like rational insights or intuitions used to justify basic logical or mathematical principles, are normally excluded from it. There are different senses in which knowledge may be said to depend on experience. In order to know

6106-596: The responsibility for issuing warnings for land areas about tropical cyclones affecting their country, such as the Joint Typhoon Warning Center for United States agencies, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) for interests in the island archipelago nation, and the Hong Kong Observatory for storms that come close enough to cause the issuance of warning signals . The list of names consists of entries from 14 southeast and east Asian nations and regions and

6192-498: The role of neutral arbiter between Newton's and Einstein's theory of gravitation by confirming Einstein's theory. For scientific consensus, it is central that evidence is public and uncontroversial, like observable physical objects or events and unlike private mental states. This way it can act as a shared ground for proponents of competing theories. Two issues threatening this role are the problem of underdetermination and theory-ladenness . The problem of underdetermination concerns

6278-458: The sea surface temperature and circulation features following a near-10-year frequency. Most tropical cyclones form on the side of the subtropical ridge closer to the equator, then move poleward past the ridge axis before recurving north and northeast into the main belt of the westerlies . Most typhoons form in a region in the northwest Pacific known as typhoon alley, where the planet's most powerful tropical cyclones most frequently develop. When

6364-426: The spirit of empiricism insofar as the restriction to experience still applies to knowledge about the external world. In some fields, like metaphysics or ethics , the choice between empiricism and rationalism makes a difference not just for how a given claim is justified but for whether it is justified at all. This is best exemplified in metaphysics, where empiricists tend to take a skeptical position, thereby denying

6450-572: The strongest Philippine typhoon on record, was a November typhoon. The most frequently impacted areas of the Philippines by tropical cyclones are northern and central Luzon and eastern Visayas . A ten-year average of satellite determined precipitation showed that at least 30 percent of the annual rainfall in the northern Philippines could be traced to tropical cyclones, while the southern islands receive less than 10 percent of their annual rainfall from tropical cyclones. The genesis and intensity of typhoons are also modulated by slow variation of

6536-582: The subtropical ridge position, shift westward across the western Pacific Ocean, which increases the landfall threat to China and greater intensity to Philippines . Those that form near the Marshall Islands find their way to Jeju Island , Korea. Typhoon paths follow three general directions. A rare few storms, like Hurricane John , were redesignated as typhoons as they originated in the Eastern/Central Pacific and moved into

6622-480: The subtropical ridge shifts due to El Niño , so will the preferred tropical cyclone tracks. Areas west of Japan and Korea tend to experience many fewer September–November tropical cyclone impacts during El Niño and neutral years. During El Niño years, the break in the subtropical ridge tends to lie near 130°E , which would favor the Japanese archipelago. During La Niña years, the formation of tropical cyclones, and

6708-532: The western Pacific basin and the North Atlantic basin, however. When one basin is active, the other is normally quiet, and vice versa. The main reason for this appears to be the phase of the Madden–Julian oscillation, or MJO, which is normally in opposite modes between the two basins at any given time. Nearly one-third of the world's tropical cyclones form within the western Pacific. This makes this basin

6794-469: The western Pacific. Within the Western Pacific, RSMC Tokyo-Typhoon Center , part of the Japan Meteorological Agency , has had the official warning responsibility for the whole of the Western Pacific since 1989, and the naming responsibility for systems of tropical storm strength or greater since 2000. However each National Meteorological and Hydrological Service within the western Pacific has

6880-419: The year. Like any tropical cyclone, there are several main requirements for typhoon formation and development. It must be in sufficiently warm sea surface temperatures , atmospheric instability, high humidity in the lower-to-middle levels of the troposphere , have enough Coriolis effect to develop a low pressure centre , a pre-existing low level focus or disturbance, and a low vertical wind shear . Although

6966-524: Was adopted officially. It was first used during the 1831-1836 "Darwin voyage" of HMS Beagle under Captain Robert FitzRoy , who was later to set up the first Meteorological Office in Britain giving regular weather forecasts. The initial scale of 13 classes (zero to 12) did not reference wind speed numbers, but related qualitative wind conditions to effects on the sails of a frigate , then

7052-601: Was extended in 1946 when forces 13 to 17 were added. However, forces 13 to 17 were intended to apply only to special cases, such as tropical cyclones . Nowadays, the extended scale is used in Taiwan, mainland China and Vietnam, which are often affected by typhoons . Internationally, the World Meteorological Organization Manual on Marine Meteorological Services (2012 edition) defined the Beaufort Scale only up to force 12 and there

7138-792: Was no recommendation on the use of the extended scale. The scale is used in the Shipping Forecasts broadcast on BBC Radio 4 in the United Kingdom, and in the Sea Area Forecast from Met Éireann , the Irish Meteorological Service. Met Éireann issues a "Small Craft Warning" if winds of Beaufort force 6 (mean wind speed exceeding 22 knots) are expected up to 10 nautical miles offshore. Other warnings are issued by Met Éireann for Irish coastal waters, which are regarded as extending 30 miles out from

7224-456: Was no standard scale and so they could be very subjective — one man's "stiff breeze" might be another's "soft breeze"—: Beaufort succeeded in standardising a scale. The scale was devised in 1805 by Francis Beaufort (later Rear Admiral ), a hydrographer and a Royal Navy officer, while serving on HMS  Woolwich , and refined until he was Hydrographer of the Navy in the 1830s, when it

7310-435: Was not dominant until Chu Coching , the head of meteorology of the national academy from 1929 to 1936, declared it to be the standard term. There were 29 alternative terms for typhoon recorded in a chronicle in 1762, now mostly replaced by 颱風 , although 風癡 or 風颱 continues to be used in Min Chinese - and Wu Chinese - speaking areas from Chaozhou , Guangdong to Taizhou , Zhejiang. Some English linguists proposed

7396-509: Was produced by a fire but not if it was produced by a smoke generator. This position has problems in explaining why it is still rational for the subject to believe that there is a fire even though the olfactory experience cannot be considered evidence. In philosophy of science, evidence is understood as that which confirms or disconfirms scientific hypotheses and arbitrates between competing theories. Measurements of Mercury's "anomalous" orbit, for example, constitute evidence that plays

#231768