161-454: Sir Robert Alexander Watson-Watt KCB FRS FRAeS (13 April 1892 – 5 December 1973) was a Scottish radio engineer and pioneer of radio direction finding and radar technology. Watt began his career in radio physics with a job at the Met Office , where he began looking for accurate ways to track thunderstorms using the radio waves given off by lightning . This led to
322-572: A lightning storm , is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere , known as thunder . Relatively weak thunderstorms are sometimes called thundershowers . Thunderstorms occur in a type of cloud known as a cumulonimbus . They are usually accompanied by strong winds and often produce heavy rain and sometimes snow , sleet , or hail , but some thunderstorms produce little precipitation or no precipitation at all. Thunderstorms may line up in
483-524: A 'command and control air defence reporting system' with several layers of reporting that were eventually sent to a single large room for mapping. Observers watching the maps would then tell the fighters what to do via direct communications. By 1937, the first three stations were ready, and the associated system was put to the test. The results were encouraging, and the government immediately commissioned construction of 17 additional stations. This became Chain Home ,
644-628: A BBC short-wave transmitter were bounced off a Handley Page Heyford aircraft. Watt led the development of a practical version of this device, which entered service in 1938 under the code name Chain Home . This system provided the vital advance information that helped the Royal Air Force in the Battle of Britain . After the success of his invention, Watson Watt was sent to the U.S. in 1941 to advise on air defence after Japan's attack on Pearl Harbor . He returned and continued to lead radar development for
805-651: A T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes. Doppler radar data, photogrammetry , and ground swirl patterns (cycloidal marks) may also be analyzed to determine intensity and award a rating. Waterspouts have similar characteristics as tornadoes, characterized by a spiraling funnel-shaped wind current that form over bodies of water, connecting to large cumulonimbus clouds. Waterspouts are generally classified as forms of tornadoes, or more specifically, non- supercelled tornadoes that develop over large bodies of water. These spiralling columns of air frequently develop within tropical areas close to
966-518: A candidate to receive his knighthood , of which ritual bathing (as a symbol of purification ) was an element. While not all knights went through such an elaborate ceremony, knights so created were known as "knights of the Bath". George I constituted the Knights of the Bath as a regular military order . He did not revive the order, which did not previously exist, in the sense of a body of knights governed by
1127-510: A clear return signal from a Handley Page Heyford bomber flown around the site. Prime Minister Stanley Baldwin was kept quietly informed of radar progress. On 2 April 1935, Watson-Watt received a patent on a radio device for detecting and locating an aircraft. In mid-May 1935, Wilkins left the Radio Research Station with a small party, including Edward George Bowen , to start further research at Orford Ness , an isolated peninsula on
1288-528: A death-ray, the concept clearly had potential, but the Air Ministry, before giving funding, asked for a demonstration proving that radio waves could be reflected by an aircraft. This was ready by 26 February and consisted of two receiving antennae located about 6 miles (10 km) away from one of the BBC 's shortwave broadcast stations at Daventry . The two antennae were phased such that signals travelling directly from
1449-481: A deviation in their course at a right angle to the wind shear direction. Thunderstorms result from the rapid upward movement of warm, moist air, sometimes along a front . However, some kind of cloud forcing , whether it is a front, shortwave trough, or another system is needed for the air to rapidly accelerate upward. As the warm, moist air moves upward, it cools, condenses , and forms a cumulonimbus cloud that can reach heights of over 20 kilometres (12 mi). As
1610-548: A fixed radar radio tower system, attempting to detect an incoming bomber by radio signals for interception by a fighter. The tests were a complete failure, with the fighter only seeing the bomber after it had passed its target. The problem was not the radar but the flow of information from trackers from the Observer Corps to the fighters, which took many steps and was very slow. Henry Tizard , Patrick Blackett , and Hugh Dowding immediately set to work on this problem, designing
1771-404: A high frequency for cloud-to-ground lightning, like Florida, lightning causes several fatalities per year, most commonly to people working outside. Acid rain is also a frequent risk produced by lightning. Distilled water has a neutral pH of 7. "Clean" or unpolluted rain has a slightly acidic pH of about 5.2, because carbon dioxide and water in the air react together to form carbonic acid ,
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#17328449359191932-500: A local thunderstorm. During a thunderstorm, pollen grains can absorb moisture and then burst into much smaller fragments with these fragments being easily dispersed by wind. While larger pollen grains are usually filtered by hairs in the nose, the smaller pollen fragments are able to pass through and enter the lungs, triggering the asthma attack. Most thunderstorms come and go fairly uneventfully; however, any thunderstorm can become severe , and all thunderstorms, by definition, present
2093-547: A mystery challenger on the American television programme To Tell The Truth . In 1956, Watson-Watt reportedly was pulled over for speeding in Canada by a radar gun -toting policeman. His remark was, "Had I known what you were going to do with it I would never have invented it!". He wrote an ironic poem ("A Rough Justice") afterwards, Pity Sir Robert Watson-Watt, strange target of this radar plot And thus, with others I can mention,
2254-399: A part of Prospect , the "union for professionals". The union speculates that at this time he was involved in campaigning for an improvement in pay for Air Ministry staff. In his English History 1914–1945 , the historian A. J. P. Taylor paid the highest of praise to Watson-Watt, Sir Henry Tizard and their associates who developed radar, crediting them with being fundamental to victory in
2415-457: A problematic business and financial life. Watson-Watt was married on 20 July 1916 in Hammersmith, London to Margaret Robertson (d.1988), the daughter of a draughtsman; they later divorced and he remarried in 1952 in Canada. His second wife was Jean Wilkinson, who died in 1964. He returned to Scotland in the 1960s. In 1966, at the age of 74, he proposed to Dame Katherine Trefusis Forbes , who
2576-505: A prominent feature and tracking it from scan to scan. A back-building thunderstorm, commonly referred to as a training thunderstorm , is a thunderstorm in which new development takes place on the upwind side (usually the west or southwest side in the Northern Hemisphere ), such that the storm seems to remain stationary or propagate in a backward direction. Though the storm often appears stationary on radar, or even moving upwind, this
2737-509: A red ring bearing the motto of the Order in gold letters. The circle is flanked by two laurel branches , and is above a scroll bearing the words Ich dien (older German for 'I serve') in gold letters. Stylised versions of this are known as Bath stars , and are used as epaulette pips to indicate British Army officer ranks and for police ranks . The star for civil Knights and Dames Grand Cross consists of an eight-pointed silver star, without
2898-451: A scroll bearing the words Ich dien in gold letters. The civil badge is a plain gold oval, bearing three crowns on the obverse side, and a rose, a thistle and a shamrock , emanating from a sceptre on the reverse side; both emblems are surrounded by a ring bearing the motto of the Order. On certain ' collar days ' designated by the Sovereign, members attending formal events may wear
3059-445: A series or become a rainband , known as a squall line . Strong or severe thunderstorms include some of the most dangerous weather phenomena, including large hail, strong winds, and tornadoes . Some of the most persistent severe thunderstorms, known as supercells , rotate as do cyclones. While most thunderstorms move with the mean wind flow through the layer of the troposphere that they occupy, vertical wind shear sometimes causes
3220-749: A set of statutes and whose numbers were replenished when vacancies occurred. The Order consists of the Sovereign of the United Kingdom (currently King Charles III ), the Great Master (currently William, Prince of Wales ), and three Classes of members: Members belong to either the Civil Division or the Military Division. Knight Companion (KB), the order's only class prior to 1815, is no longer an option. Commonwealth citizens who are not subjects of
3381-562: A storm arises quickly and unexpectedly. Preparing the home by removing dead or rotting limbs and trees, which can be blown over in high winds, can also significantly reduce the risk of property damage and personal injury. The National Weather Service (NWS) in the United States recommends several precautions that people should take if thunderstorms are likely to occur: While safety and preparedness often overlap, "thunderstorm safety" generally refers to what people should do during and after
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#17328449359193542-421: A storm. The American Red Cross recommends that people follow these precautions if a storm is imminent or in progress: The NWS stopped recommending the "lightning crouch" in 2008 as it does not provide a significant level of protection and will not significantly lower the risk of being killed or injured from a nearby lightning strike. Thunderstorms occur throughout the world, even in the polar regions, with
3703-683: A weak acid (pH 5.6 in distilled water), but unpolluted rain also contains other chemicals. Nitric oxide present during thunderstorm phenomena, caused by the oxidation of atmospheric nitrogen, can result in the production of acid rain, if nitric oxide forms compounds with the water molecules in precipitation, thus creating acid rain. Acid rain can damage infrastructures containing calcite or certain other solid chemical compounds. In ecosystems, acid rain can dissolve plant tissues of vegetations and increase acidification process in bodies of water and in soil , resulting in deaths of marine and terrestrial organisms. Any thunderstorm that produces hail that reaches
3864-412: A wide range of frequencies and could be easily detected and amplified by naval longwave sets. In fact, lightning was a major problem for communications at these common wavelengths. His early experiments were successful in detecting the signal and he quickly proved to be able to do so at ranges up to 2,500 km (1500 miles). Location was determined by rotating a loop antenna to maximise (or minimise)
4025-461: Is a polar molecule that can carry a charge, so it is capable of creating the charge separation needed to produce lightning). These electrical discharges can be up to a thousand times more powerful than lightning on the Earth. The water clouds can form thunderstorms driven by the heat rising from the interior. The clouds of Venus may also be capable of producing lightning ; some observations suggest that
4186-596: Is a complex of thunderstorms that becomes organized on a scale larger than the individual thunderstorms but smaller than extratropical cyclones , and normally persists for several hours or more. A mesoscale convective system's overall cloud and precipitation pattern may be round or linear in shape, and include weather systems such as tropical cyclones , squall lines , lake-effect snow events, polar lows , and mesoscale convective complexes (MCCs), and they generally form near weather fronts . Most mesoscale convective systems develop overnight and continue their lifespan through
4347-455: Is a gold Maltese Cross of eight points, enamelled in white. Each point of the cross is decorated by a small gold ball; each angle has a small figure of a lion. The centre of the cross bears three crowns on the obverse side, and a rose, a thistle and a shamrock , emanating from a sceptre on the reverse side. Both emblems are surrounded by a red circular ring bearing the motto of the Order, which are in turn flanked by two laurel branches, above
4508-435: Is an illusion. The storm is really a multi-cell storm with new, more vigorous cells that form on the upwind side, replacing older cells that continue to drift downwind. When this happens, catastrophic flooding is possible. In Rapid City, South Dakota , in 1972, an unusual alignment of winds at various levels of the atmosphere combined to produce a continuously training set of cells that dropped an enormous quantity of rain upon
4669-589: Is being turned to the still difficult, but less unpromising, problem of radio detection and numerical considerations on the method of detection by reflected radio waves will be submitted when required". Wilkins's idea, checked by Watt, was promptly presented by Tizard to the CSSAD on 28 January 1935. On 12 February 1935, Watson-Watt sent the secret memo of the proposed system to the Air Ministry , Detection and location of aircraft by radio methods . Although not as exciting as
4830-588: Is clear at least that he set out to make himself indispensable to the Earl Marshal , which was not hard, their political principles being congruous and their friendship already established, but also to Sir Robert Walpole and the Whig ministry, which can by no means have been easy, considering his known attachment to the Pretender and the circumstances under which he came into office. ... The main object of Anstis's next move,
4991-400: Is estimated that huff-duff was used in about a quarter of all attacks on U-boats. In 1935, Watt was asked to comment on reports of a German death ray based on radio. Watt and his assistant Arnold Frederic Wilkins quickly determined it was not possible, but Wilkins suggested using radio signals to locate aircraft at long distances. This led to a February 1935 demonstration where signals from
Robert Watson-Watt - Misplaced Pages Continue
5152-461: Is in turn larger than the Companion's badge; however, these are all suspended on a crimson ribbon. Knights and Dames Grand Cross wear the badge on a riband or sash, passing from the right shoulder to the left hip. Knights Commander and male Companions wear the badge from a ribbon worn around the neck. Dames Commander and female Companions wear the badge from a bow on the left side: The military badge
5313-474: Is issued if a thunderstorm becomes severe, or will soon turn severe. In Canada, a rainfall rate greater than 50 millimetres (2 in) in one hour, or 75 millimetres (3 in) in three hours, is also used to indicate severe thunderstorms. Severe thunderstorms can occur from any type of storm cell. However, multicell , supercell , and squall lines represent the most common forms of thunderstorms that produce severe weather. A mesoscale convective system (MCS)
5474-556: Is known, then the total energy of a thunderstorm can be calculated. In a typical thunderstorm, approximately 5×10 kg of water vapor are lifted, and the amount of energy released when this condenses is 10 joules . This is on the same order of magnitude of energy released within a tropical cyclone, and more energy than that released during the atomic bomb blast at Hiroshima, Japan in 1945 . The Fermi Gamma-ray Burst Monitor results show that gamma rays and antimatter particles ( positrons ) can be generated in powerful thunderstorms. It
5635-525: Is little wind shear , the storm will rapidly enter the dissipating stage and 'rain itself out', but, if there is sufficient change in wind speed or direction, the downdraft will be separated from the updraft, and the storm may become a supercell , where the mature stage can sustain itself for several hours. In the dissipation stage, the thunderstorm is dominated by the downdraft. If atmospheric conditions do not support super cellular development, this stage occurs rather quickly, approximately 20–30 minutes into
5796-437: Is made of black velvet ; it includes an upright plume of feathers . The collar , worn only by Knights and Dames Grand Cross, is made of gold and weighs 30 troy ounces (933 g) . It consists of depictions of nine imperial crowns and eight sets of flowers ( roses for England, thistles for Scotland, and shamrocks for Ireland), connected by seventeen silver knots. On lesser occasions, simpler insignia are used: The star
5957-422: Is mainly inflicted by downburst winds, large hailstones, and flash flooding caused by heavy precipitation . Stronger thunderstorm cells are capable of producing tornadoes and waterspouts . There are three types of thunderstorms: single-cell , multi-cell , and supercell . Supercell thunderstorms are the strongest and most severe. Mesoscale convective systems formed by favorable vertical wind shear within
6118-468: Is more of a factor with thunderstorms with heavy precipitation (HP) than with thunderstorms with low precipitation (LP). When thunderstorms merge, which is most likely when numerous thunderstorms exist in proximity to each other, the motion of the stronger thunderstorm normally dictates the future motion of the merged cell. The stronger the mean wind, the less likely other processes will be involved in storm motion. On weather radar , storms are tracked by using
6279-741: Is not falling through the updraft) with a strong, rotating updraft (a " mesocyclone "). These storms normally have such powerful updrafts that the top of the supercell storm cloud (or anvil) can break through the troposphere and reach into the lower levels of the stratosphere . Supercell storms can be 24 kilometres (15 mi) wide. Research has shown that at least 90 percent of supercells cause severe weather . These storms can produce destructive tornadoes , extremely large hailstones (10 centimetres or 4 inches diameter), straight-line winds in excess of 130 km/h (81 mph), and flash floods . In fact, research has shown that most tornadoes occur from this type of thunderstorm. Supercells are generally
6440-412: Is one of the most significant thunderstorm hazards to aircraft. When hail stones exceed 13 millimetres (0.5 in) in diameter, planes can be seriously damaged within seconds. The hailstones accumulating on the ground can also be hazardous to landing aircraft. Wheat, corn, soybeans, and tobacco are the most sensitive crops to hail damage. Hail is one of Canada's most costly hazards. Hailstorms have been
6601-411: Is suggested that the antimatter positrons are formed in terrestrial gamma-ray flashes (TGF). TGFs are brief bursts occurring inside thunderstorms and associated with lightning. The streams of positrons and electrons collide higher in the atmosphere to generate more gamma rays. About 500 TGFs may occur every day worldwide, but mostly go undetected. In more contemporary times, thunderstorms have taken on
Robert Watson-Watt - Misplaced Pages Continue
6762-584: Is the Great Master, of which there have been ten: Originally a Prince of the Blood Royal, as the Principal Knight Companion, ranked next after the sovereign. This position was joined to that of the Great Master in the statutes of 1847. The Great Master and Principal Knight is now either a descendant of George I or 'some other exalted personage'; the holder of the office has custody of the seal of
6923-586: Is the most common type of thunderstorm development. Mature thunderstorms are found near the center of the cluster, while dissipating thunderstorms exist on their downwind side. Multicell storms form as clusters of storms but may then evolve into one or more squall lines . While each cell of the cluster may only last 20 minutes, the cluster itself may persist for hours at a time. They often arise from convective updrafts in or near mountain ranges and linear weather boundaries, such as strong cold fronts or troughs of low pressure. These type of storms are stronger than
7084-426: Is used only by Knights and Dames Grand Cross and Knights and Dames Commander. Its style varies by rank and division; it is worn pinned to the left breast: The star for military Knights and Dames Grand Cross consists of a Maltese Cross on top of an eight-pointed silver star; the star for military Knights and Dames Commander is an eight-pointed silver cross pattée. Each bears in the centre three crowns surrounded by
7245-437: Is usually caused by the heavy liquid precipitation that accompanies it. Flash floods are most common in arid regions as well as densely populated urban environments, where few plants, and bodies of water are present to absorb and contain the extra water. Flash flooding can be hazardous to small infrastructure, such as bridges, and weakly constructed buildings. Plants and crops in agricultural areas can be destroyed and devastated by
7406-661: The Doppler on Wheels , vehicles with mounted automated weather stations , weather balloons , and unmanned aircraft to investigate thunderstorms expected to produce severe weather. Lightning is detected remotely using sensors that detect cloud-to-ground lightning strokes with 95 percent accuracy in detection and within 250 metres (820 ft) of their point of origin. Thunderstorms strongly influenced many early civilizations. Greeks believed that they were battles waged by Zeus , who hurled lightning bolts forged by Hephaestus . Some American Indian tribes associated thunderstorms with
7567-490: The Earth's atmosphere . In the mature stage of a thunderstorm, the warmed air continues to rise until it reaches an area of warmer air and can rise no farther. Often this 'cap' is the tropopause . The air is instead forced to spread out, giving the storm a characteristic anvil shape. The resulting cloud is called cumulonimbus incus . The water droplets coalesce into larger and heavier droplets and freeze to become ice particles. As these fall, they melt to become rain. If
7728-438: The Earth's atmosphere . Weaker thunderstorms are steered by winds closer to the Earth's surface than stronger thunderstorms, as the weaker thunderstorms are not as tall. Organized, long-lived thunderstorm cells and complexes move at a right angle to the direction of the vertical wind shear vector. If the gust front, or leading edge of the outflow boundary, races ahead of the thunderstorm, its motion will accelerate in tandem. This
7889-651: The Gulf War . A more controversial member of the Order was Robert Mugabe , whose honour was stripped by the Queen, on the advice of the Foreign Secretary , David Miliband , on 25 June 2008 "as a mark of revulsion at the abuse of human rights and abject disregard for the democratic process in Zimbabwe over which President Mugabe has presided." Honorary members do not count towards the numerical limits in each class. In addition,
8050-742: The Order of the Garter ). Foreign generals are also often given honorary appointments to the Order, for example: Marshal Ferdinand Foch and Marshal Joseph Joffre during the First World War ; Marshal Georgy Zhukov , King Abdul-Aziz of Saudi Arabia , General Dwight D. Eisenhower , General George C. Marshall , General Douglas MacArthur , and General George S. Patton Jr. during the Second World War ; and General Norman Schwarzkopf and General Colin Powell after
8211-645: The Pearl Harbor attack . He was knighted by George VI in 1942 and received the US Medal for Merit in 1946. Ten years after his knighthood, Watson-Watt was awarded £50,000 by the UK government for his contributions in the development of radar. He established a practice as a consulting engineer. In the 1950s, he moved to Canada and later he lived in the US, where he published Three Steps to Victory in 1958. Around 1958, he appeared as
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#17328449359198372-628: The Rocky Mountains as part of the North American Monsoon regime. In the Northeast , storms take on similar characteristics and patterns as the Midwest, but with less frequency and severity. During the summer, air-mass thunderstorms are an almost daily occurrence over central and southern parts of Florida. If the quantity of water that is condensed in and subsequently precipitated from a cloud
8533-463: The Second World War . In July 1938, Watson-Watt left Bawdsey Manor and took up the post of Director of Communications Development (DCD-RAE). In 1939, Sir George Lee took over the job of DCD and Watson-Watt became Scientific Advisor on Telecommunications (SAT) to the Ministry of Aircraft Production , travelling to the US in 1941 to advise them on the severe inadequacies of their air defence, illustrated by
8694-517: The Thunderbird , who they believed was a servant of the Great Spirit . The Norse considered thunderstorms to occur when Thor went to fight Jötnar , with the thunder and lightning being the effect of his strikes with the hammer Mjölnir . Hinduism recognizes Indra as the god of rain and thunderstorms. Christian doctrine accepts that fierce storms are the work of God. These ideas were still within
8855-537: The United States rainfall climatology over the Great Plains since they bring the region about half of their annual warm season rainfall. The two major ways thunderstorms move are via advection of the wind and propagation along outflow boundaries towards sources of greater heat and moisture. Many thunderstorms move with the mean wind speed through the Earth's troposphere , the lowest 8 kilometres (5.0 mi) of
9016-708: The War Office and Ministry of Supply . He was elected a Fellow of the Royal Society in 1941, was given a knighthood in 1942 and was awarded the US Medal for Merit in 1946. Watson-Watt was born in Brechin , Angus, Scotland , on 13 April 1892. He claimed to be a descendant of James Watt , the famous engineer and inventor of the practical steam engine , but no evidence of any family relationship has been found. After attending Damacre Primary School and Brechin High School , he
9177-437: The equator , but are less common within areas of high latitude . Flash flooding is the process where a landscape, most notably an urban environment, is subjected to rapid floods. These rapid floods occur more quickly and are more localized than seasonal river flooding or areal flooding and are frequently (though not always) associated with intense rainfall. Flash flooding can frequently occur in slow-moving thunderstorms and
9338-418: The lifted index can be used to assist in determining potential upward vertical development of clouds. Generally, thunderstorms require three conditions in order to form: All thunderstorms, regardless of type, go through three stages: the developing stage , the mature stage , and the dissipation stage . The average thunderstorm has a 24 km (15 mi) diameter. Depending on the conditions present in
9499-417: The spurs to the knight-elect's heels, fastened a belt around his waist, then struck him on the neck (with either a hand or a sword ), thus making him a knight. It was this accolade which was the essential act in creating a knight, and a simpler ceremony developed, conferring knighthood merely by striking or touching the knight-to-be on the shoulder with a sword, or 'dubbing' him, as is still done today. In
9660-504: The water vapor in that rising air condenses . When the moisture condenses, it releases energy known as latent heat of condensation, which allows the rising packet of air to cool less than the cooler surrounding air continuing the cloud's ascension. If enough instability is present in the atmosphere, this process will continue long enough for cumulonimbus clouds to form and produce lightning and thunder . Meteorological indices such as convective available potential energy (CAPE) and
9821-434: The 1859 revision. Women were admitted to the Order in 1971. In the 1971 New Year Honours , Jean Nunn became the first woman admitted to the order. In 1975, Princess Alice, Duchess of Gloucester , an aunt of Elizabeth II , became the first woman to reach the highest rank, Dame Grand Cross. Princess Alice (née Douglas-Montagu-Scott) was a direct descendant of the Order's first Great Master, and her husband, who had died
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#17328449359199982-475: The 18th century. Beyond the Earth's atmosphere, thunderstorms have also been observed on the planets of Jupiter , Saturn , Neptune , and, probably, Venus . Warm air has a lower density than cool air, so warmer air rises upwards and cooler air will settle at the bottom (this effect can be seen with a hot air balloon ). Clouds form as relatively warmer air, carrying moisture, rises within cooler air. The moist air rises, and, as it does so, it cools and some of
10143-451: The 1920s development of a system later known as high-frequency direction finding (HFDF or "huff-duff"). Although well publicized at the time, the system's enormous military potential was not developed until the late 1930s. Huff-duff allowed operators to determine the location of an enemy radio transmitter in seconds and it became a major part of the network of systems that helped defeat the threat of German U-boats during World War II . It
10304-587: The Air Ministry. He asked Watson-Watt about the possibility of building their version of a death-ray, specifically to be used against aircraft. Watson-Watt quickly returned a calculation carried out by his young colleague, Arnold Wilkins , showing that such a device was impossible to construct, and fears of a Nazi version soon vanished. He also mentioned in the same report a suggestion that was originally made to him by Wilkins, who had recently heard of aircraft disturbing shortwave communications , that radio waves might be capable of detecting aircraft, "Meanwhile, attention
10465-670: The British monarch and foreign nationals may be made honorary members. The Order of the Bath is the fourth most senior of the British orders of chivalry , after the Order of the Garter , the Order of the Thistle , and the (dormant) Order of St Patrick . In the Middle Ages , a knighthood was often conferred with elaborate ceremonies. These usually involved the knight-to-be taking a bath (possibly symbolic of spiritual purification ), during which he
10626-701: The British monarch and foreigners may be made honorary members. Queen Elizabeth II established the custom of appointing visiting (republican) heads of state honorary GCBs, for example Gustav Heinemann and Josip Broz Tito (in 1972), Ronald Reagan (in 1989), Lech Wałęsa (in 1991), Censu Tabone (in 1992), Fernando Henrique Cardoso , George H. W. Bush (in 1993), Nicolas Sarkozy (in 2008), and Susilo Bambang Yudhoyono (in 2012), as well as Turkish President Abdullah Gül , Slovenian President Danilo Türk , Mexican President Felipe Calderón , and South African President Jacob Zuma (royal heads of state are instead usually made Stranger Knights and Ladies Companion of
10787-481: The Earth's surface, occasionally causing strong winds that are commonly associated with thunderstorms. Thunderstorms can form and develop in any geographic location but most frequently within the mid-latitude , where warm, moist air from tropical latitudes collides with cooler air from polar latitudes. Thunderstorms are responsible for the development and formation of many severe weather phenomena, which can be potentially hazardous. Damage that results from thunderstorms
10948-675: The Garter equivalent (the Gentleman Usher of the Black Rod ) perform any duties in the House of Lords . There were originally seven officers, each of whom was to receive fees from the Knights Companion both on appointment, and annually thereafter. The office of Messenger was abolished in 1859. The office of Genealogist was abolished at the same time, but revived in 1913. The offices of Registrar and Secretary were formally merged in 1859, although
11109-460: The Genealogist, Brunswick Herald of Arms to the Gentleman Usher, and Bath King of Arms was also made Gloucester King of Arms with heraldic jurisdiction over Wales. This was the result of a move by Anstis to give the holders of these sinecures greater security; the offices of the Order of the Bath were held at the pleasure of the Great Master, while appointments to the heraldic offices were made by
11270-621: The King under the Great Seal and were for life. Members of the Order wear elaborate uniforms on important occasions (such as its quadrennial installation ceremonies and coronations ), which vary by rank: The mantle , worn only by Knights and Dames Grand Cross, is made of crimson satin lined with white taffeta . On the left side is a representation of the star (see below). The mantle is bound with two large tassels. The hat , worn only by Knights and Dames Grand Cross and Knights and Dames Commander,
11431-462: The Knights of the Bath, as well as the colour of the riband and mantle , and the ceremony for creating a knight. The rest of the statutes were mostly based on those of the Order of the Garter, of which he was an officer (as Garter King of Arms). The Order was founded by letters patent under the Great Seal dated 18 May 1725 ; 299 years ago ( 1725-05-18 ) , and the statutes issued
11592-528: The Maltese cross; the star for civil Knights and Dames Commander is an eight-pointed silver cross pattée. The design of each is the same as the design of the military stars, except that the laurel branches and the words Ich dien are excluded. The badge varies in design, size, and manner of wearing by rank and division. The Knight and Dame Grand Cross' badge is larger than the Knight and Dame Commander's badge, which
11753-604: The Military Division, to Commissariat and Medical officers serving with the Army and Navy , including those serving with the East India Company . In 1859, a further edition of the Statutes was issued; the changes related mainly to the costs associated with the Order. Prior to this date, it had been the policy that the insignia (which were provided by the Crown) were to be returned on
11914-461: The Order for members who had been appointed for the services in the recent war. The fees were abolished, and replaced with a salary of approximately the same average value. The offices of Genealogist and Messenger were abolished, and those of Registrar and Secretary combined. In 1910, after his accession to the throne, George V ordered the revival of the Installation ceremony, perhaps prompted by
12075-403: The Order of the Bath; a similar design of badge is still worn by members of the Civil Division. Their symbolism however is not entirely clear. The 'three joined in one' may be a reference to the kingdoms of England , Scotland , and either France or Ireland , which were held (or claimed in the case of France ) by English and, later, British monarchs. This would correspond to the three crowns in
12236-399: The Order of the Garter (or the Order of the Thistle for Scots), none of which were awarded in large numbers (the Garter and the Thistle are limited to twenty-four and sixteen living members respectively). The political environment was also significantly different from today: The Sovereign still exercised a power to be reckoned with in the eighteenth century. The Court remained the centre of
12397-420: The Order were increasingly made for naval , military , or diplomatic achievements. This is partly due to the conflicts Britain was engaged in over this period. The Peninsular War resulted in so many deserving candidates for the Bath, that a statute was issued allowing the appointment of Extra Knights in time of war, who were to be additional to the numerical limits imposed by the statutes, and whose number
12558-594: The Order's collar over their military uniform or evening wear. When collars are worn (either on collar days or on formal occasions such as coronations), the badge is suspended from the collar. The collars and badges of Knights and Dames Grand Cross are returned to the Central Chancery of the Orders of Knighthood upon the decease of their owners. All other insignia may be retained by their owners. Thunderstorm A thunderstorm , also known as an electrical storm or
12719-617: The Sky , aired with Eddie Izzard in the role of Watson Watt. A collection of some of the correspondence and papers of Watson-Watt is held by the National Library of Scotland . A collection of papers relating to Watson-Watt is also held by Archive Services at the University of Dundee . A briefing facility at RAF Boulmer has been named the Watson-Watt auditorium in his honour. Watson-Watt had
12880-573: The Suffolk coast of the North Sea. By June, they were detecting aircraft at a distance of 16 mi (26 km), which was enough for scientists and engineers to stop all work on competing sound-based detection systems . By the end of the year, the range was up to 60 mi (97 km), at which point, plans were made in December to set up five stations covering the approaches to London. One of these stations
13041-670: The air, but with the limited cruising time of a fighter, this would require a huge air force. An alternative solution was urgently needed and, in 1934, the Air Ministry set up a committee, the CSSAD ( Committee for the Scientific Survey of Air Defence ), chaired by Sir Henry Tizard to find ways to improve air defence in the UK. Rumours that Nazi Germany had developed a " death ray " that was capable of destroying towns, cities and people using radio waves, were given attention in January 1935 by Harry Wimperis , Director of Scientific Research at
13202-508: The array of fixed radar towers on the east and south coasts of England. By the start of World War II, 19 were ready for the Battle of Britain , and by the end of the war, over 50 had been built. The Germans were aware of the construction of Chain Home but were not sure of its purpose. They tested their theories with a flight of the Zeppelin LZ 130 but concluded the stations were a new long-range naval communications system. As early as 1936, it
13363-589: The atmosphere, each of these three stages take an average of 30 minutes. The first stage of a thunderstorm is the cumulus stage or developing stage. During this stage, masses of moisture are lifted upwards into the atmosphere. The trigger for this lift can be solar illumination , where the heating of the ground produces thermals , or where two winds converge forcing air upwards, or where winds blow over terrain of increasing elevation. The moisture carried upward cools into liquid drops of water due to lower temperatures at high altitude, which appear as cumulus clouds. As
13524-758: The back edge of the rain shield associated with mature squall lines, a wake low can form, which is a mesoscale low pressure area that forms behind the mesoscale high pressure system normally present under the rain canopy, which are sometimes associated with a heat burst . This kind of storm is also known as "Wind of the Stony Lake" ( simplified Chinese : 石湖风 ; traditional Chinese : 石湖風 ; shi2 hu2 feng1) in southern China. Supercell storms are large, usually severe , quasi-steady-state storms that form in an environment where wind speed or wind direction varies with height (" wind shear "), and they have separate downdrafts and updrafts (i.e., where its associated precipitation
13685-485: The badge. Another explanation of the motto is that it refers to the Holy Trinity . Nicolas quotes a source (although he is sceptical of it) who claims that prior to James I the motto was Tria numina juncta in uno (three powers/gods joined in one), but from the reign of James I, the word numina was dropped, and the motto understood to mean Tria [regna] juncta in uno (three kingdoms joined in one). The prime mover in
13846-402: The bulk of the occurrences from May through September. Cheyenne, Wyoming , is North America's most hail-prone city with an average of nine to ten hailstorms per season. In South America, areas prone to hail are cities like Bogotá, Colombia. Hail can cause serious damage, notably to automobiles , aircraft, skylights, glass-roofed structures, livestock, and most commonly, farmers' crops . Hail
14007-501: The cause of costly and deadly events throughout history. One of the earliest recorded incidents occurred around the 9th century in Roopkund , Uttarakhand, India. The largest hailstone in terms of maximum circumference and length ever recorded in the United States fell in 2003 in Aurora, Nebraska , United States. A tornado is a violent, rotating column of air in contact with both the surface of
14168-665: The churchyard of the Episcopal Church of the Holy Trinity at Pitlochry. Knight Commander of the Order of the Bath The Most Honourable Order of the Bath is a British order of chivalry founded by King George I on 18 May 1725. Recipients of the Order are usually senior military officers or senior civil servants , and the monarch awards it on the advice of His Majesty's Government. The name derives from an elaborate medieval ceremony for preparing
14329-521: The college's Engineering Department. In 1916, Watson-Watt wanted a job with the War Office , but nothing obvious was available in communications. Instead, he joined the Meteorological Office , which was interested in his ideas on the use of radio for the detection of thunderstorms . Lightning gives off a radio signal as it ionizes the air, and his goal was to detect this signal to warn pilots of approaching thunderstorms. The signal occurs across
14490-431: The danger of lightning . Thunderstorm preparedness and safety refers to taking steps before, during, and after a thunderstorm to minimize injury and damage. Preparedness refers to precautions that should be taken before a thunderstorm. Some preparedness takes the form of general readiness (as a thunderstorm can occur at any time of the day or year). Preparing a family emergency plan, for example, can save valuable time if
14651-461: The death of the holder; the exception had been foreigners who had been awarded honorary membership. In addition, foreigners had usually been provided with stars made of silver and diamonds, whereas ordinary members had only embroidered stars. The decision was made to award silver stars to all members, and only require the return of the Collar . The Crown had also been paying the fees due to the officers of
14812-497: The development of organized convection. This term technically applies to a single thunderstorm with one main updraft. Also known as air-mass thunderstorms , these are the typical summer thunderstorms in many temperate locales. They also occur in the cool unstable air that often follows the passage of a cold front from the sea during winter. Within a cluster of thunderstorms, the term "cell" refers to each separate principal updraft. Thunderstorm cells occasionally form in isolation, as
14973-506: The early medieval period, the difference seems to have been that the full ceremonies were used for men from more prominent families. From the coronation of Henry IV in 1399, the full ceremonies were restricted to major royal occasions, such as coronations, investitures of the Prince of Wales or royal dukes , and royal weddings, and the knights so created became known as Knights of the Bath . Knights Bachelor continued to be created with
15134-637: The earth and a cumulonimbus cloud (otherwise known as a thundercloud) or, in rare cases, the base of a cumulus cloud . Tornadoes come in many sizes but are typically in the form of a visible condensation funnel , whose narrow end touches the earth and is often encircled by a cloud of debris and dust . Most tornadoes have wind speeds between 40 and 110 mph (64 and 177 km/h), are approximately 75 metres (246 ft) across, and travel several kilometers (a few miles) before dissipating. Some attain wind speeds of more than 300 mph (480 km/h), stretch more than 1,600 metres (1 mi) across, and stay on
15295-561: The establishment of the Order of the Bath was John Anstis , Garter King of Arms , England's highest heraldic officer. Sir Anthony Wagner , a recent holder of the office of Garter King of Arms, wrote of Anstis's motivations: It was Martin Leake's opinion that the trouble and opposition Anstis met with in establishing himself as Garter so embittered him against the heralds that when at last in 1718 he succeeded, he made it his prime object to aggrandise himself and his office at their expense. It
15456-426: The fact that the Bath was represented as a military Order, only a few military officers were among the initial appointments (see List of knights companion of the Order of the Bath ). They may be broken down into categories as follows (some are classified in more than one category): The majority of the new Knights Companions were knighted by the King, and invested with their ribands and badges on 27 May 1725. Although
15617-404: The fighters that close. Bowen decided that an airborne radar should not exceed 90 kg (200 lb ) in weight or 8 ft³ (230 L ) in volume and should require no more than 500 watts of power. To reduce the drag of the antennae, the operating wavelength could not be much greater than one metre, difficult for the day's electronics. However, aircraft interception (AI) radar was perfected by 1940 and
15778-473: The first Installation ceremony of the more junior Order of St Michael and St George , held a few years earlier, and the building of a new chapel for the Order of the Thistle in 1911. The Installation ceremony took place on 22 July 1913 in the Henry VII Chapel , and Installations have been held at regular intervals since. Prior to the 1913 Installation, it was necessary to adapt the chapel to accommodate
15939-403: The following week. The Order initially consisted of the Sovereign, a Prince of the blood Royal as Principal Knight, a Great Master, and thirty-five Knights Companion. Seven officers (see below) were attached to the Order. These provided yet another opportunity for political patronage, as they were to be sinecures at the disposal of the Great Master, supported by fees from the knights. Despite
16100-429: The force exerted by downburst winds. Downburst winds are usually formed in areas when high pressure air systems of downdrafts begin to sink and displace the air masses below it, due to their higher density. When these downdrafts reach the surface, they spread out and turn into the destructive straight-horizontal winds. Thunderstorm asthma is the triggering of an asthma attack by environmental conditions directly caused by
16261-739: The force of raging water. Automobiles parked within affected areas can also be displaced. Soil erosion can occur as well, exposing risks of landslide phenomena. Downburst winds can produce numerous hazards to landscapes experiencing thunderstorms. Downburst winds are generally very powerful, and are often mistaken for wind speeds produced by tornadoes, due to the concentrated amount of force exerted by their straight-horizontal characteristic. Downburst winds can be hazardous to unstable, incomplete, or weakly constructed infrastructures and buildings. Agricultural crops, and other plants in nearby environments can be uprooted and damaged. Aircraft engaged in takeoff or landing can crash. Automobiles can be displaced by
16422-427: The form of strong straight-line winds can be expected in areas where the squall line itself is in the shape of a bow echo , within the portion of the line that bows out the most. Tornadoes can be found along waves within a line echo wave pattern , or LEWP, where mesoscale low pressure areas are present. Some bow echoes in the summer are called derechos , and move quite fast through large sections of territory. On
16583-579: The greatest frequency in tropical rainforest areas, where they may occur nearly daily. At any given time, approximately 2,000 thunderstorms are occurring on Earth. Kampala and Tororo in Uganda have each been mentioned as the most thunderous places on Earth, a claim also made for Singapore and Bogor on the Indonesian island of Java . Other cities known for frequent storm activity include Darwin , Caracas, Manila and Mumbai . Thunderstorms are associated with
16744-469: The ground for more than 100 kilometres (dozens of miles). The Fujita scale and the Enhanced Fujita Scale rate tornadoes by damage caused. An EF0 tornado, the weakest category, damages trees but does not cause significant damage to structures. An EF5 tornado, the strongest category, rips buildings off their foundations and can deform large skyscrapers. The similar TORRO scale ranges from
16905-449: The ground is known as a hailstorm. Thunderclouds that are capable of producing hailstones are often seen obtaining green coloration. Hail is more common along mountain ranges because mountains force horizontal winds upwards (known as orographic lifting ), thereby intensifying the updrafts within thunderstorms and making hail more likely. One of the more common regions for large hail is across mountainous northern India, which reported one of
17066-410: The highest hail-related death tolls on record in 1888. China also experiences significant hailstorms. Across Europe, Croatia experiences frequent occurrences of hail. In North America, hail is most common in the area where Colorado , Nebraska , and Wyoming meet, known as "Hail Alley". Hail in this region occurs between the months of March and October during the afternoon and evening hours, with
17227-514: The holder of the Chair of Physics at University College, Dundee from 1907 to 1942. It was Peddie who encouraged Watson-Watt to study radio , or "wireless telegraphy" as it was then known, and who took him through what was effectively a postgraduate class on the physics of radio frequency oscillators and wave propagation . At the start of the Great War Watson-Watt was working as an assistant in
17388-402: The instability and relative wind conditions at different layers of the atmosphere (" wind shear "). Single-cell thunderstorms form in environments of low vertical wind shear and last only 20–30 minutes. Organized thunderstorms and thunderstorm clusters/lines can have longer life cycles as they form in environments of significant vertical wind shear, normally greater than 25 knots (13 m/s) in
17549-493: The larger number of members. An appeal was made to the members of the Order, and following the Installation a surplus remained. A Committee was formed from the Officers to administer the 'Bath Chapel Fund', and over time this committee has come to consider other matters than purely financial ones. Another revision of the statutes of the Order was undertaken in 1925, to consolidate the 41 additional statutes which had been issued since
17710-532: The life of the thunderstorm. The downdraft will push down out of the thunderstorm, hit the ground and spread out. This phenomenon is known as a downburst . The cool air carried to the ground by the downdraft cuts off the inflow of the thunderstorm, the updraft disappears and the thunderstorm will dissipate. Thunderstorms in an atmosphere with virtually no vertical wind shear weaken as soon as they send out an outflow boundary in all directions, which then quickly cuts off its inflow of relatively warm, moist air, and kills
17871-609: The lowest 6 kilometres (3.7 mi) of the troposphere , which aids the development of stronger updrafts as well as various forms of severe weather. The supercell is the strongest of the thunderstorms, most commonly associated with large hail, high winds, and tornado formation. Precipitable water values of greater than 31.8 millimetres (1.25 in) favor the development of organized thunderstorm complexes. Those with heavy rainfall normally have precipitable water values greater than 36.9 millimetres (1.45 in). Upstream values of CAPE of greater than 800 J/kg are usually required for
18032-449: The mainstream as late as the 18th century. Martin Luther was out walking when a thunderstorm began, causing him to pray to God for being saved and promising to become a monk. Thunderstorms, evidenced by flashes of lightning , on Jupiter have been detected and are associated with clouds where water may exist as both a liquid and ice, suggesting a mechanism similar to that on Earth. (Water
18193-404: The marks of distinction which they have so nobly earned. The Order was now to consist of three classes: Knights Grand Cross, Knights Commander, and Companions. At the same time, the large and small Naval Gold Medals were suspended, while the bearers became Knights Commander and Companions, respectively. The existing Knights Companion (of which there were 60) became Knight Grand Cross; this class
18354-653: The most powerful thunderstorms over the United States occur in the Midwest and the Southern states . These storms can produce large hail and powerful tornadoes. Thunderstorms are relatively uncommon along much of the West Coast of the United States , but they occur with greater frequency in the inland areas, particularly the Sacramento and San Joaquin Valleys of California. In spring and summer, they occur nearly daily in certain areas of
18515-400: The new Order for Walpole was that it would provide a source of such favours to strengthen his political position. He made sure that most of the 36 new honorees were peers and MPs who would provide him with useful connections. George I having agreed to Walpole's proposal, Anstis was commissioned to draft statutes for the Order of the Bath. As noted above, he adopted the motto and badge used by
18676-530: The next day. They tend to form when the surface temperature varies by more than 5 °C (9 °F) between day and night. The type that forms during the warm season over land has been noted across North America, Europe, and Asia, with a maximum in activity noted during the late afternoon and evening hours. Forms of MCS that develop in the tropics are found in use either the Intertropical Convergence Zone or monsoon troughs , generally within
18837-526: The occurrence of one thunderstorm can develop an outflow boundary that sets up new thunderstorm development. Such storms are rarely severe and are a result of local atmospheric instability; hence the term "air mass thunderstorm". When such storms have a brief period of severe weather associated with them, it is known as a pulse severe storm. Pulse severe storms are poorly organized and occur randomly in time and space, making them difficult to forecast. Single-cell thunderstorms normally last 20–30 minutes. This
18998-476: The opportunity also taken to regularise the 1815 expansion of the Order. The 1847 statutes also abolished all the medieval ritual, but they did introduce a formal Investiture ceremony, conducted by the Sovereign wearing the Mantle and insignia of the Order, attended by the Officers and as many GCBs as possible, in their Mantles. In 1850, a special statute authorised appointments of Knight Commander and Companion, in
19159-458: The order and is responsible for enforcing the statutes. The statutes also provide for the following: Regular membership is limited to citizens of the United Kingdom and of other Commonwealth countries of which the British monarch is Sovereign. Appointees are usually officers of the armed forces or senior civil servants, such as permanent secretaries . Members appointed to the Civil Division must "by their personal services to [the] crown or by
19320-597: The performance of public duties have merited ... royal favour." Appointments to the Military Division are restricted by the minimum rank of the individual. GCBs hold the rank of admiral in the Royal Navy, general in the British Army or Royal Marines , or air chief marshal in the Royal Air Force . KCBs must at least hold the rank of vice admiral , lieutenant general in the Army or Marines, or air marshal . CBs tend be of
19481-498: The phenomena of thunderstorms and have numerous hazards towards landscapes and populations. One of the more significant hazards lightning can pose is the wildfires they are capable of igniting. Under a regime of low precipitation (LP) thunderstorms, where little precipitation is present, rainfall cannot prevent fires from starting when vegetation is dry as lightning produces a concentrated amount of extreme heat. Direct damage caused by lightning strikes occurs on occasion. In areas with
19642-522: The political world. The King was limited in that he had to choose Ministers who could command a majority in Parliament , but the choice remained his. The leader of an administration still had to command the King's personal confidence and approval. A strong following in Parliament depended on being able to supply places, pensions, and other marks of Royal favour to the government's supporters. The attraction of
19803-450: The prestige of the Order. In 1847, Queen Victoria issued new statutes eliminating all references to an exclusively military Order. As well as removing the word 'Military' from the full name of the Order, this opened up the grades of Knight Commander and Companion to civil appointments, and the Military and Civil Divisions of the Order were established. New numerical limits were imposed, and
19964-456: The previous year, had also held that office. The second Dame Grand Cross, Sally Davies , was appointed in the 2020 New Year Honours . The British Sovereign is the Sovereign of the Order of the Bath. As with all honours, except those in the Sovereign's personal gift, the Sovereign makes all appointments to the Order on the advice of the Government . The next-most senior member of the Order
20125-552: The rank of rear admiral , major general in the Army, Royal Navy or Royal Marines, or air vice marshal in the Royal Air Force, and in addition must have been Mentioned in Despatches for distinction in a command position in a combat situation, although the latter is no longer a requirement. Non-line officers (e.g. engineers , medics) may be appointed only for meritorious service in wartime. Commonwealth citizens not subjects of
20286-515: The revival or institution of the Order of the Bath was probably that which it in fact secured, of ingratiating him with the all-powerful Prime Minister Sir Robert Walpole. The use of honours in the early eighteenth century differed considerably from the modern honours system , in which hundreds, if not thousands, of people each year receive honours on the basis of deserving accomplishments. The only honours available at that time were hereditary (not life) peerages and baronetcies , knighthoods , and
20447-426: The rising air reaches its dew point temperature, water vapor condenses into water droplets or ice, reducing pressure locally within the thunderstorm cell. Any precipitation falls the long distance through the clouds towards the Earth's surface. As the droplets fall, they collide with other droplets and become larger. The falling droplets create a downdraft as it pulls cold air with it, and this cold air spreads out at
20608-489: The role of a scientific curiosity. Every spring, storm chasers head to the Great Plains of the United States and the Canadian Prairies to explore the scientific aspects of storms and tornadoes through use of videotaping. Radio pulses produced by cosmic rays are being used to study how electric charges develop within thunderstorms. More organized meteorological projects such as VORTEX2 use an array of sensors, such as
20769-503: The same area, resulting in devastating flash flooding . A similar event occurred in Boscastle , England, on 16 August 2004, and over Chennai on 1 December 2015. Each year, many people are killed or seriously injured by severe thunderstorms despite the advance warning . While severe thunderstorms are most common in the spring and summer, they can occur at just about any time of the year. Cloud-to-ground lightning frequently occurs within
20930-709: The signal, thus "pointing" to the storm. The strikes were so fleeting that it was very difficult to turn the antenna in time to positively locate one. Instead, the operator would listen to many strikes and develop a rough average location. At first, he worked at the Wireless Station of Air Ministry Meteorological Office in Aldershot , Hampshire . In 1924 when the War Department gave notice that they wished to reclaim their Aldershot site, he moved to Ditton Park near Slough , Berkshire . The National Physical Laboratory (NPL)
21091-403: The simpler form of ceremony. The last occasion on which Knights of the Bath were created was the coronation of Charles II in 1661. From at least 1625, and possibly from the reign of James I , Knights of the Bath were using the motto Tria juncta in uno ( Latin for 'Three joined in one'), and wearing as a badge three crowns within a plain gold oval. These were both subsequently adopted by
21252-526: The single-cell storm, yet much weaker than the supercell storm. Hazards with the multicell cluster include moderate-sized hail, flash flooding, and weak tornadoes. A squall line is an elongated line of severe thunderstorms that can form along or ahead of a cold front . In the early 20th century, the term was used as a synonym for cold front . The squall line contains heavy precipitation , hail , frequent lightning , strong straight line winds, and possibly tornadoes and waterspouts . Severe weather in
21413-711: The squegger so that the dot arrived at the far end of the display at the same time as expected signals reflected off the Heaviside layer, the altitude of the layer could be determined. This time-base circuit was key to the development of radar. After a further reorganization in 1933, Watt became Superintendent of the Radio Department of NPL in Teddington . During the First World War , the Germans had used Zeppelins as long-range bombers over Britain and defences had struggled to counter
21574-401: The station cancelled themselves out, but signals arriving from other angles were admitted, thereby deflecting the trace on a CRT indicator ( passive radar ). Such was the secrecy of this test that only three people witnessed it: Watson-Watt, his colleague Arnold Wilkins, and a single member of the committee, A. P. Rowe . The demonstration was a success: on several occasions, the receiver showed
21735-626: The statutes allow the Sovereign to exceed the limits in time of war or other exceptional circumstances. The office of Dean is held by the Dean of Westminster . The King of Arms, responsible for heraldry , is known as Bath King of Arms; he is not, however, a member of the College of Arms , like many heralds. The Order's Usher is known as the Gentleman Usher of the Scarlet Rod ; he does not, unlike his Order of
21896-405: The statutes set out the full medieval ceremony which was to be used for creating knights, this was not performed, and indeed, was possibly never intended to be, as the original statutes contained a provision allowing the Great Master to dispense Knights Companion from these requirements. The original knights were dispensed from all the medieval ceremonies with the exception of the Installation, which
22057-443: The strongest type of thunderstorm. In the United States, a thunderstorm is classed as severe if winds reach at least 93 kilometres per hour (58 mph), hail is 25 millimetres (1 in) in diameter or larger, or if funnel clouds or tornadoes are reported. Although a funnel cloud or tornado indicates a severe thunderstorm, a tornado warning is issued in place of a severe thunderstorm warning . A severe thunderstorm warning
22218-632: The threat. Since that time, aircraft capabilities had improved considerably and the prospect of widespread aerial bombardment of civilian areas was causing the government anxiety. Heavy bombers were now able to approach at altitudes that anti-aircraft guns of the day were unable to reach. With enemy airfields across the English Channel potentially only 20 minutes' flying-time away, bombers would have dropped their bombs and be returning to base before any intercepting fighters could get to altitude. The only answer seemed to be to have standing patrols of fighters in
22379-592: The thunderstorm's further growth. The downdraft hitting the ground creates an outflow boundary . This can cause downbursts, a potential hazardous condition for aircraft to fly through, as a substantial change in wind speed and direction occurs, resulting in a decrease of airspeed and the subsequent reduction in lift for the aircraft. The stronger the outflow boundary is, the stronger the resultant vertical wind shear becomes. There are four main types of thunderstorms: single-cell, multi-cell, squall line (also called multi-cell line) and supercell. Which type forms depends on
22540-453: The tropics and subtropics can be responsible for the development of hurricanes . Dry thunderstorms , with no precipitation, can cause the outbreak of wildfires from the heat generated from the cloud-to-ground lightning that accompanies them. Several means are used to study thunderstorms: weather radar , weather stations , and video photography. Past civilizations held various myths concerning thunderstorms and their development as late as
22701-515: The two positions had been held concurrently for the previous century. An Officer of Arms and a Secretary for the Knights Commander and Companions were established in 1815, but abolished in 1847. The office of Deputy Secretary was created in 1925. Under the Hanoverian kings, certain of the officers also held heraldic office. The office of Blanc Coursier Herald of Arms was attached to that of
22862-552: The updraft is strong enough, the droplets are held aloft long enough to become so large that they do not melt completely but fall as hail . While updrafts are still present, the falling rain drags the surrounding air with it, creating downdrafts as well. The simultaneous presence of both an updraft and a downdraft marks the mature stage of the storm and produces cumulonimbus clouds. During this stage, considerable internal turbulence can occur, which manifests as strong winds, severe lightning, and even tornadoes . Typically, if there
23023-453: The upper atmosphere. This was the first direct indication of the reality of the Heaviside layer , proposed earlier, but at this time largely dismissed by engineers. To determine the altitude of the layer, Watt, Appleton and others developed the ' squegger ' to develop a ' time base ' display, which would cause the oscilloscope's dot to move smoothly across the display at very high speed. By timing
23184-464: The various monsoon seasons around the globe, and they populate the rainbands of tropical cyclones . In temperate regions, they are most frequent in spring and summer, although they can occur along or ahead of cold fronts at any time of year. They may also occur within a cooler air mass following the passage of a cold front over a relatively warmer body of water. Thunderstorms are rare in polar regions because of cold surface temperatures. Some of
23345-509: The victim of his own invention. His magical all-seeing eye enabled cloud-bound planes to fly but now by some ironic twist it spots the speeding motorist and bites, no doubt with legal wit, the hand that once created it. ... On 3 September 2014, a statue of Sir Robert Watson-Watt was unveiled in Brechin by the Princess Royal . One day later, the BBC Two drama Castles in
23506-539: The warm season between spring and fall. More intense systems form over land than over water. One exception is that of lake-effect snow bands, which form due to cold air moving across relatively warm bodies of water, and occurs from fall through spring. Polar lows are a second special class of MCS. They form at high latitudes during the cold season. Once the parent MCS dies, later thunderstorm development can occur in connection with its remnant mesoscale convective vortex (MCV). Mesoscale convective systems are important to
23667-454: The water vapor condenses into liquid, latent heat is released, which warms the air, causing it to become less dense than the surrounding, drier air. The air tends to rise in an updraft through the process of convection (hence the term convective precipitation ). This process creates a low-pressure zone within and beneath the forming thunderstorm. In a typical thunderstorm, approximately 500 million kilograms of water vapor are lifted into
23828-685: Was 67 years old at the time and had also played a significant role in the Battle of Britain as the founding Air Commander of the Women's Auxiliary Air Force , which supplied the radar-room operatives. They lived together in London in the winter, and at "The Observatory": Trefusis Forbes' summer home in Pitlochry , Perthshire , during the warmer months. They remained together until her death in 1971. Watson-Watt died in 1973, aged 81, in Inverness . They are buried together in
23989-488: Was a problem. This was solved by the second device, the WE-224 oscilloscope , recently acquired from Bell Labs . By feeding the signals from the two antennae into the X and Y channels of the oscilloscope, a single strike caused the appearance of a line on the display, indicating the direction of the strike. The scope's relatively "slow" phosphor only allowed the signal to be read long after the strike had occurred. Watt's new system
24150-507: Was accepted at University College, Dundee (then part of the University of St Andrews and which became Queen's College, Dundee in 1954 and then the University of Dundee in 1967). Watson-Watt had a successful time as a student, winning the Carnelley Prize for Chemistry and a class medal for Ordinary Natural Philosophy in 1910. He graduated with a BSc in engineering in 1912, and was offered an assistantship by Professor William Peddie ,
24311-413: Was already using this site and had two main devices that would prove pivotal to his work. The first was an Adcock antenna , an arrangement of four masts that allowed the direction of a signal to be detected through phase differences. Using pairs of these antennas positioned at right angles, one could make a simultaneous measurement of the lightning's direction on two axes. Displaying the fleeting signals
24472-582: Was also to appoint eight officers for this body. However, the statute was never invoked. In January 1815, after the end of the Peninsular War , the Prince Regent (later George IV ) expanded the Order of the Bath to the end that those Officers who have had the opportunities of signalising themselves by eminent services during the late war may share in the honours of the said Order, and that their names may be delivered down to remote posterity, accompanied by
24633-480: Was being used in 1926 and was the topic of an extensive paper by Watson-Watt and Herd. The Met and NPL radio teams were amalgamated in 1927 to form the Radio Research Station with Watson-Watt as director. Continuing research throughout, the teams had become interested in the causes of "static" radio signals and found that much could be explained by distant signals located over the horizon being reflected off
24794-400: Was instructed in the duties of knighthood by more senior knights. He was then put to bed to dry. Clothed in a special robe, he was led with music to the chapel where he spent the night in a vigil . At dawn, he made confession and attended Mass , then retired to his bed to sleep until it was fully daylight. He was then brought before the King, who after instructing two senior knights to buckle
24955-456: Was instrumental in eventually ending The Blitz of 1941. Watson-Watt justified his choice of a non-optimal frequency for his radar, with his oft-quoted "cult of the imperfect" , which he stated as "Give them the third-best to go on with; the second-best comes too late; the best never comes". Between 1934 and 1936, Watson-Watt was president of the Institution of Professional Civil Servants , now
25116-456: Was limited to 72 members, of which twelve could be appointed for civil or diplomatic services. The military members had to be of the rank of at least major-general or rear admiral . The Knights Commander were limited to 180, exclusive of foreign nationals holding British commissions, up to ten of whom could be appointed as honorary Knights Commander. They had to be of the rank of lieutenant-colonel or post-captain . The number of Companions
25277-517: Was not specified, but they had to have received a medal or been mentioned in despatches since the start of the war in 1803. A list of about 500 names was subsequently published. Two further officers were appointed, an 'Officer of arms attendant on the Knights Commanders and Companions', and a 'Secretary appertaining to the Knights Commanders and Companions'. The large increase in numbers caused some complaints that such an expansion would reduce
25438-427: Was not subject to any restrictions. Another statute, this one issued some 80 years earlier, had also added a military note to the Order. Each knight was required, under certain circumstances, to supply and support four men-at-arms for a period not exceeding 42 days in any year, to serve in any part of Great Britain. This company was to be captained by the Great Master, who had to supply four trumpeters , and
25599-464: Was performed in the Order's Chapel, the Henry VII Chapel in Westminster Abbey , on 17 June. This precedent was followed until 1812, after which the Installation was also dispensed with, until its revival in the twentieth century. The ceremonies however remained part of the Statutes until 1847. Although the initial appointments to the Order were largely political, from the 1770s, appointments to
25760-458: Was realized that the Luftwaffe would turn to night bombing if the day campaign did not go well. Watson-Watt had put another of the staff from the Radio Research Station, Edward Bowen, in charge of developing a radar that could be carried by a fighter. Night-time visual detection of a bomber was good to about 300 m and the existing Chain Home systems simply did not have the accuracy needed to get
25921-515: Was to be located on the coast near Orford Ness , and Bawdsey Manor was selected to become the main centre for all radar research. To put a radar defence in place as quickly as possible, Watson-Watt and his team created devices using existing components, rather than creating new components for the project, and the team did not take additional time to refine and improve the devices. So long as the prototype radars were in workable condition, they were put into production. They conducted "full scale" tests of
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