1.
Hurricane Paul (2006)
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Hurricane Paul was a hurricane that ultimately struck Mexico as a tropical depression in October 2006. It developed from an area of disturbed weather on October 21, Paul attained hurricane status on October 23, and later that day it reached its peak intensity of 105 mph, a strong Category 2 hurricane on the Saffir-Simpson scale. A strong trough turned the hurricane to the north and northeast into an area of vertical shear. It accelerated northeastward, and after passing a short distance south of Baja California Sur the low level circulation became decoupled from the rest of the convection. Paul weakened to a depression on October 25 a short distance off the coast of Mexico. Paul was the hurricane to threaten western Mexico in the season. Rough surf killed two people along Baja California Sur, while flooding was reported in Sinaloa, damage totaled more than $35 million. A tropical wave moved off the coast of Africa on October 4 and it moved westward across the Atlantic Ocean without development, and entered the eastern Pacific Ocean on October 18. The next day, it combined with an existing area of disturbed weather. The broad and disorganized system moved westward at 10–15 mph, on October 20, the system developed an area of low pressure, and began to show signs of organization. It continued to organize, and developed into Tropical Depression Seventeen-E on October 21 while located about 265 miles south-southwest of Manzanillo, upon forming, the depression possessed a small, tight low-level circulation beneath a well-defined mid-level circulation. Easterly wind shear initially restricted upper-level outflow as the cyclone moved to the west, the low level circulation gradually became more embedded within the convection as the cloud pattern improved. Early on October 22, wind shear began to decrease, which coincided with an increase of outflow on its eastern side, the storm temporarily degraded in appearance as it turned to the northwest. However, shear sharply abated over Paul late on October 22, resulting in the storm quickly gaining organization, an eye began to develop within the convection, and Paul intensified into a hurricane early on October 23. On October 23, while located 465 miles south-southwest of Cabo San Lucas, Paul reached its intensity of 105 mph. A large trough located off the west coast of California turned the hurricane to the north-northwest, the combination of increasing shear and dry air quickly weakened Paul to a tropical storm on October 24 as its low-level circulation became detached from the diminishing convection. The storm then turned to the northeast after passing near Socorro Island, despite increasing wind shear of over 50 mph, Paul remained a tropical storm while its circulation remained on the southwest side of its developing deep convection. Early on October 25, the storm passed about 100 miles south of the tip of Baja California
2.
Weather map
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A weather map displays various Meteorological features across a particular area at a particular point in time and has various symbols which all have specific meanings. Such maps have been in use since the century and are used for research. Maps using isotherms show temperature gradients, which can help locate weather fronts, isotach maps, analyzing lines of equal wind speed, on a constant pressure surface of 300 mb or 250 mb show where the jet stream is located. Use of constant pressure charts at the 700 and 500 hPa level can indicate tropical cyclone motion, a popular type of surface weather map is the surface weather analysis, which plots isobars to depict areas of high pressure and low pressure. Cloud codes are translated into symbols and plotted on these maps along with other data that are included in synoptic reports sent by professionally trained observers. The use of charts in a modern sense began in the middle portion of the 19th century in order to devise a theory on storm systems. In England, the scientist Francis Galton heard of this work and he used his map to prove that air circulated clockwise around areas of high pressure, he coined the term anticyclone to describe the phenomenon. He was also instrumental in publishing the first weather map in a newspaper, the Times began printing weather maps using these methods with data from the Meteorological Office. It was also important for time to be standardized across time zones so that the information on the map should accurately represent the weather at a given time. A standardized time system was first used to coordinate the British railway network in 1847, in the USA, The Smithsonian Institution developed its network of observers over much of the central and eastern United States between the 1840s and 1860s once Joseph Henry took the helm. The U. S. Army Signal Corps inherited this network between 1870 and 1874 by an act of Congress, and expanded it to the west coast soon afterwards, at first, not all the data on the map was used due to a lack of time standardization. The United States fully adopted time zones in 1905, when Detroit finally established standard time, the use of frontal zones on weather maps began in the 1910s in Norway. Polar front theory is attributed to Jacob Bjerknes, derived from a network of observation sites in Norway during World War I. This theory proposed that the inflow into a cyclone was concentrated along two lines of convergence, one ahead of the low and another trailing behind the low. The convergence line ahead of the low known as either the steering line or the warm front. The trailing convergence zone was referred to as the line or cold front. Areas of clouds and rainfall appeared to be focused along these convergence zones, the concept of frontal zones led to the concept of air masses. The nature of the structure of the cyclone would wait for the development of the upper air network during the 1940s
3.
Weather
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Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the lowest level of the atmosphere, Weather refers to day-to-day temperature and precipitation activity, whereas climate is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualification, weather is understood to mean the weather of Earth. Weather is driven by air pressure, temperature and moisture differences between one place and another and these differences can occur due to the suns angle at any particular spot, which varies with latitude. The strong temperature contrast between polar and tropical air gives rise to the largest scale atmospheric circulations, the Hadley Cell, the Ferrel Cell, the Polar Cell, Weather systems in the mid-latitudes, such as extratropical cyclones, are caused by instabilities of the jet stream flow. Because the Earths axis is tilted relative to its orbital plane, on Earths surface, temperatures usually range ±40 °C annually. Over thousands of years, changes in Earths orbit can affect the amount and distribution of energy received by the Earth, thus influencing long-term climate. Surface temperature differences in turn cause pressure differences, higher altitudes are cooler than lower altitudes as most atmospheric heating is due to contact with the Earths surface while radiative losses to space are mostly constant. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. The Earths weather system is a system, as a result. Human attempts to control the weather have occurred throughout history, and there is evidence that human activities such as agriculture, studying how the weather works on other planets has been helpful in understanding how weather works on Earth. A famous landmark in the Solar System, Jupiters Great Red Spot, is a storm known to have existed for at least 300 years. However, weather is not limited to planetary bodies, a stars corona is constantly being lost to space, creating what is essentially a very thin atmosphere throughout the Solar System. The movement of mass ejected from the Sun is known as the solar wind, on Earth, the common weather phenomena include wind, cloud, rain, snow, fog and dust storms. Less common events include natural disasters such as tornadoes, hurricanes, typhoons, almost all familiar weather phenomena occur in the troposphere. Weather does occur in the stratosphere and can affect weather lower down in the troposphere, Weather occurs primarily due to air pressure, temperature and moisture differences between one place to another. These differences can occur due to the sun angle at any particular spot, in other words, the farther from the tropics one lies, the lower the sun angle is, which causes those locations to be cooler due the spread of the sunlight over a greater surface. The strong temperature contrast between polar and tropical air gives rise to the large scale atmospheric circulation cells and the jet stream, Weather systems in the mid-latitudes, such as extratropical cyclones, are caused by instabilities of the jet stream flow
4.
Atmospheric pressure
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Atmospheric pressure, sometimes also called barometric pressure, is the pressure exerted by the weight of air in the atmosphere of Earth. In most circumstances atmospheric pressure is approximated by the hydrostatic pressure caused by the weight of air above the measurement point. As elevation increases, there is less overlying atmospheric mass, so that atmospheric pressure decreases with increasing elevation. On average, a column of air one square centimetre in cross-section, measured from sea level to the top of the atmosphere, has a mass of about 1.03 kilograms and that force is a pressure of 10.1 N/cm2 or 101 kN/m2. A column 1 square inch in cross-section would have a weight of about 14.7 lb or about 65.4 N and it is modified by the planetary rotation and local effects such as wind velocity, density variations due to temperature and variations in composition. The standard atmosphere is a unit of pressure defined as 101325 Pa, the mean sea level pressure is the average atmospheric pressure at sea level. This is the pressure normally given in weather reports on radio, television. When barometers in the home are set to match the weather reports, they measure pressure adjusted to sea level. The altimeter setting in aviation, is an atmospheric pressure adjustment, average sea-level pressure is 1013.25 mbar. In aviation weather reports, QNH is transmitted around the world in millibars or hectopascals, except in the United States, Canada, however, in Canadas public weather reports, sea level pressure is instead reported in kilopascals. The highest sea-level pressure on Earth occurs in Siberia, where the Siberian High often attains a sea-level pressure above 1050 mbar, the lowest measurable sea-level pressure is found at the centers of tropical cyclones and tornadoes, with a record low of 870 mbar. Pressure varies smoothly from the Earths surface to the top of the mesosphere, although the pressure changes with the weather, NASA has averaged the conditions for all parts of the earth year-round. As altitude increases, atmospheric pressure decreases, one can calculate the atmospheric pressure at a given altitude. Temperature and humidity affect the atmospheric pressure, and it is necessary to know these to compute an accurate figure. The graph at right was developed for a temperature of 15 °C, at low altitudes above the sea level, the pressure decreases by about 1.2 kPa for every 100 meters. See pressure system for the effects of air pressure variations on weather, Atmospheric pressure shows a diurnal or semidiurnal cycle caused by global atmospheric tides. This effect is strongest in tropical zones, with an amplitude of a few millibars and these variations have two superimposed cycles, a circadian cycle and semi-circadian cycle. The highest adjusted-to-sea level barometric pressure recorded on Earth was 1085.7 hPa measured in Tosontsengel
5.
Temperature
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A temperature is an objective comparative measurement of hot or cold. It is measured by a thermometer, several scales and units exist for measuring temperature, the most common being Celsius, Fahrenheit, and, especially in science, Kelvin. Absolute zero is denoted as 0 K on the Kelvin scale, −273.15 °C on the Celsius scale, the kinetic theory offers a valuable but limited account of the behavior of the materials of macroscopic bodies, especially of fluids. Temperature is important in all fields of science including physics, geology, chemistry, atmospheric sciences, medicine. The Celsius scale is used for temperature measurements in most of the world. Because of the 100 degree interval, it is called a centigrade scale.15, the United States commonly uses the Fahrenheit scale, on which water freezes at 32°F and boils at 212°F at sea-level atmospheric pressure. Many scientific measurements use the Kelvin temperature scale, named in honor of the Scottish physicist who first defined it and it is a thermodynamic or absolute temperature scale. Its zero point, 0K, is defined to coincide with the coldest physically-possible temperature and its degrees are defined through thermodynamics. The temperature of zero occurs at 0K = −273. 15°C. For historical reasons, the triple point temperature of water is fixed at 273.16 units of the measurement increment, Temperature is one of the principal quantities in the study of thermodynamics. There is a variety of kinds of temperature scale and it may be convenient to classify them as empirically and theoretically based. Empirical temperature scales are historically older, while theoretically based scales arose in the middle of the nineteenth century, empirically based temperature scales rely directly on measurements of simple physical properties of materials. For example, the length of a column of mercury, confined in a capillary tube, is dependent largely on temperature. Such scales are only within convenient ranges of temperature. For example, above the point of mercury, a mercury-in-glass thermometer is impracticable. A material is of no use as a thermometer near one of its phase-change temperatures, in spite of these restrictions, most generally used practical thermometers are of the empirically based kind. Especially, it was used for calorimetry, which contributed greatly to the discovery of thermodynamics, nevertheless, empirical thermometry has serious drawbacks when judged as a basis for theoretical physics. Theoretically based temperature scales are based directly on theoretical arguments, especially those of thermodynamics, kinetic theory and they rely on theoretical properties of idealized devices and materials
6.
Cloud cover
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Cloud cover refers to the fraction of the sky obscured by clouds when observed from a particular location. Okta is the unit of measurement of the cloud cover. The cloud cover is correlated to the duration as the least cloudy locales are the sunniest ones while the cloudiest areas are the least sunny places. The global cloud cover averages around 0.68 when analysing clouds with optical depth larger than 0.1 and this value is lower when considering clouds with an optical depth larger than 2 and higher when counting subvisible cirrus clouds. Clouds play multiple roles in the climate system. In particular, being bright objects in the part of the solar spectrum, they efficiently reflect light to space. Cloud cover thus plays an important role in the balance of the atmosphere. Cloud cover values only vary by 0.03 from year to year, whereas the local, most data sets agree on the fact that the land is covered by 0. 10-0.15 less cloud than the oceans. Lastly, there is a variation in the cloud cover. Almost the same variation is found 20°S, on the other hand, in the storm regions of the Southern Hemisphere midlatitudes were found to have with 0. 15-0.25 more cloudiness than the global mean at 60°S. On average, about 52% of Earth is cloud-covered at any moment, some regions are almost always cloudy such as the Amazon Rainforest and some others are almost always clear such as the Sahara Desert
7.
Cartography
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Cartography is the study and practice of making maps. Combining science, aesthetics, and technique, cartography builds on the premise that reality can be modeled in ways that communicate spatial information effectively, the fundamental problems of traditional cartography are to, Set the maps agenda and select traits of the object to be mapped. This is the concern of map editing, traits may be physical, such as roads or land masses, or may be abstract, such as toponyms or political boundaries. Represent the terrain of the object on flat media. This is the concern of map projections, eliminate characteristics of the mapped object that are not relevant to the maps purpose. This is the concern of generalization, reduce the complexity of the characteristics that will be mapped. This is also the concern of generalization, orchestrate the elements of the map to best convey its message to its audience. This is the concern of map design, modern cartography constitutes many theoretical and practical foundations of geographic information systems. The earliest known map is a matter of debate, both because the term map isnt well-defined and because some artifacts that might be maps might actually be something else. A wall painting that might depict the ancient Anatolian city of Çatalhöyük has been dated to the late 7th millennium BCE, the oldest surviving world maps are from 9th century BCE Babylonia. One shows Babylon on the Euphrates, surrounded by Assyria, Urartu and several cities, all, in turn, another depicts Babylon as being north of the world center. The ancient Greeks and Romans created maps since Anaximander in the 6th century BCE, in the 2nd century AD, Ptolemy wrote his treatise on cartography, Geographia. This contained Ptolemys world map – the world known to Western society. As early as the 8th century, Arab scholars were translating the works of the Greek geographers into Arabic, in ancient China, geographical literature dates to the 5th century BCE. The oldest extant Chinese maps come from the State of Qin, dated back to the 4th century BCE, in the book of the Xin Yi Xiang Fa Yao, published in 1092 by the Chinese scientist Su Song, a star map on the equidistant cylindrical projection. Early forms of cartography of India included depictions of the pole star and these charts may have been used for navigation. Mappa mundi are the Medieval European maps of the world, approximately 1,100 mappae mundi are known to have survived from the Middle Ages. Of these, some 900 are found illustrating manuscripts and the remainder exist as stand-alone documents, the Arab geographer Muhammad al-Idrisi produced his medieval atlas Tabula Rogeriana in 1154
8.
Synoptic scale meteorology
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The synoptic scale in meteorology is a horizontal length scale of the order of 1000 kilometres or more. This corresponds to a horizontal scale typical of mid-latitude depressions, most high and low-pressure areas seen on weather maps such as surface weather analyses are synoptic-scale systems, driven by the location of Rossby waves in their respective hemisphere. Low-pressure areas and their related frontal zones occur on the edge of a trough within the Rossby wave pattern. Most precipitation areas occur near frontal zones, the word synoptic is derived from the Greek word συνοπτικός, meaning seen together. The Navier–Stokes equations applied to atmospheric motion can be simplified by scale analysis in the synoptic scale and it can be shown that the main terms in horizontal equations are Coriolis force and pressure gradient terms, therefore, one can use geostrophic approximation. In vertical coordinates, the equation simplifies to the hydrostatic equilibrium equation. The first weather maps in the 19th century were drawn well after the fact to help devise a theory on storm systems, use of surface analyses began first in the United States, spreading worldwide during the 1870s. Use of the Norwegian cyclone model for frontal analysis began in the late 1910s across Europe, surface weather analyses have special symbols which show frontal systems, cloud cover, precipitation, or other important information. For example, an H represents high pressure, implying good, an L represents low pressure, which frequently accompanies precipitation. Various symbols are used not just for frontal zones and other surface boundaries on weather maps, areas of precipitation help determine the frontal type and location. Mesoscale systems and boundaries such as cyclones, outflow boundaries. Isobars are commonly used to place surface boundaries from the horse latitudes poleward, the descriptor extratropical refers to the fact that this type of cyclone generally occurs outside of the tropics, in the middle latitudes of the planet. These are the phenomena which along with anti-cyclones, drive the weather over much of the Earth. An extratropical cyclone can transform into a storm, and from there into a tropical cyclone, if it dwells over warm waters and develops central convection. High-pressure systems are associated with light winds at the surface and subsidence through the lower portion of the troposphere. Subsidence will generally dry out an air mass by adiabatic, or compressional, thus, high pressure typically brings clear skies. During the day, since no clouds are present to reflect sunlight, there is more incoming solar radiation. At night, the absence of means that outgoing longwave radiation is not absorbed
9.
Weather front
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A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena outside the tropics. In surface weather analyses, fronts are depicted using various colored triangles and half-circles, the air masses separated by a front usually differ in temperature and humidity. Cold fronts may feature narrow bands of thunderstorms and severe weather, Warm fronts are usually preceded by stratiform precipitation and fog. The weather usually clears quickly after a fronts passage, some fronts produce no precipitation and little cloudiness, although there is invariably a wind shift. Cold fronts and occluded fronts generally move from west to east, because of the greater density of air in their wake, cold fronts and cold occlusions move faster than warm fronts and warm occlusions. Mountains and warm bodies of water can slow the movement of fronts and this is most common over the open ocean. The Bergeron classification is the most widely accepted form of air mass classification, air mass classification involves three letters. The first letter describes its moisture properties, with c used for air masses. The second letter describes the characteristic of its source region, T for tropical, P for polar, A for arctic or Antarctic, M for monsoon, E for equatorial. The third letter is used to designate the stability of the atmosphere, if the air mass is colder than the ground below it, it is labeled k. If the air mass is warmer than the ground below it, it is labeled w. Fronts separate air masses of different types or origins, Surface weather analyses have special symbols which show frontal systems, cloud cover, precipitation, or other important information. For example, an H may represent high pressure, implying fair weather, an L on the other hand may represent low pressure, which frequently accompanies precipitation. Low pressure also creates surface winds deriving from high pressure zones, various symbols are used not just for frontal zones and other surface boundaries on weather maps, but also to depict the present weather at various locations on the weather map. In addition, areas of precipitation help determine the frontal type, there are two different meanings used within meteorology to describe weather around a frontal zone. The term anafront describes boundaries which show instability, meaning air rises rapidly along, a katafront is weaker, bringing smaller changes in temperature and moisture, as well as limited rainfall. Cold fronts often bring heavy thunderstorms, rain and hail, Cold front can produce sharper changes in weather and move up to twice as quickly as warm fronts, since cold air is denser than warm air and rapidly replaces the warm air preceding the boundary. Cold fronts come in association with a low-pressure area, the concept of colder, dense air wedging under the less dense warmer air is often used to depict how air is lifted along a frontal boundary. The cold air wedging underneath warmer air creates the strongest winds just above the ground surface and this lift would then form a narrow line of showers and thunderstorms if enough moisture were present
10.
Telegraph
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Telegraphy is the long-distance transmission of textual or symbolic messages without the physical exchange of an object bearing the message. Thus semaphore is a method of telegraphy, whereas pigeon post is not, telegraphy requires that the method used for encoding the message be known to both sender and receiver. Such methods are designed according to the limits of the medium used. The use of signals, beacons, reflected light signals. In the 19th century, the harnessing of electricity led to the invention of electrical telegraphy, the advent of radio in the early 20th century brought about radiotelegraphy and other forms of wireless telegraphy. The word telegraph was first coined by the French inventor of the Semaphore line, Claude Chappe, a telegraph is a device for transmitting and receiving messages over long distances, i. e. for telegraphy. The word telegraph alone now generally refers to an electrical telegraph, Wireless telegraphy is also known as CW, for continuous wave, as opposed to the earlier radio technique of using a spark gap. Contrary to the definition used by Chappe, Morse argued that the term telegraph can strictly be applied only to systems that transmit. This is to be distinguished from semaphore, which transmits messages. Smoke signals, for instance, are to be considered semaphore, according to Morse, telegraph dates only from 1832 when Pavel Schilling invented one of the earliest electrical telegraphs. A telegraph message sent by a telegraph operator or telegrapher using Morse code was known as a telegram. A cablegram was a sent by a submarine telegraph cable. Later, a Telex was a sent by a Telex network. A wire picture or wire photo was a picture that was sent from a remote location by a facsimile telegraph. A diplomatic telegram, also known as a cable, is the term given to a confidential communication between a diplomatic mission and the foreign ministry of its parent country. These continue to be called telegrams or cables regardless of the used for transmission. Commercial electrical telegraphs were introduced from 1837, the first telegraphs came in the form of optical telegraph, including the use of smoke signals, beacons, or reflected light, which have existed since ancient times. Early proposals for a telegraph system were made to the Royal Society by Robert Hooke in 1684 and were first implemented on an experimental level by Sir Richard Lovell Edgeworth in 1767
11.
Surface weather observation
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Surface weather observations are the fundamental data used for safety as well as climatological reasons to forecast weather and issue warnings worldwide. Airport observations can be transmitted worldwide through the use of the METAR observing code, a thirty-year average of a locations weather observations is traditionally used to determine the stations climate. Surface weather observations have traditionally taken at airports due to safety concerns during takeoffs. The ICAO defines the International Standard Atmosphere, which is the model of the variation of pressure, temperature, density. This is useful in calibrating instruments and designing aircraft, and is used to reduce a stations pressure to sea level pressure where it can then be used on weather maps, in the United States, the FAA mandates the taking of weather observations at larger airports for safety reasons. To help facilitate the purchase of an automated weather station, such as ASOS. The airport observations are then transmitted using the METAR observing code. METAR reports typically come from airports or permanent weather observation stations, reports are generated once an hour, however, if conditions change significantly, they may be updated in special reports called SPECIs. For example, the first letter for areas in and around the Pacific Ocean is P, the second character may represent the country/state the location lies within. For Hawaii, the first two letters are PH while for Great Britain, the first two letters of the station identifier are EG, canada and the contiguous United States are an exception, with the first letters C and K representing the regions, respectively. The final two or three letters normally represent the name of the location or airport, visibility, measured in meters for most sites worldwide, except in the United States where statute miles are reported. Runway visibility, measured in meters in many locations worldwide, or feet within the United States, temperature is a measure of the kinetic energy of a sample of matter. Temperature is the physical property that determines the direction of heat flow between two objects placed in thermal contact. If no heat flow occurs, the two objects have the same temperature, otherwise heat flows from the object to the colder object. Temperature, within meteorology, is measured with thermometers exposed to the air, in most of the world, the degree Celsius scale is used for most temperature measuring purposes. However, the United States is the last major country in which the degree Fahrenheit temperature scale is used by most lay people, industry, popular meteorology, despite this, METAR reports from the United States also report the temperature in degrees Celsius. Dew point is the temperature to which a parcel of air must be cooled, at constant atmospheric pressure. The condensed water is called dew, the dew point is a saturation point
12.
Smithsonian Institution
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The Smithsonian Institution, established in 1846 for the increase and diffusion of knowledge, is a group of museums and research centers administered by the Government of the United States. Originally organized as the United States National Museum, that ceased to exist as an administrative entity in 1967. Additional facilities are located in Arizona, Maryland, Massachusetts, New York City, Texas, Virginia, more than 200 institutions and museums in 45 states, Puerto Rico, and Panama are Smithsonian Affiliates. The Institutions thirty million annual visitors are admitted without charge and its annual budget is around $1.2 billion with 2/3 coming from annual federal appropriations. Other funding comes from the Institutions endowment, private and corporate contributions, membership dues, and earned retail, concession, Institution publications include Smithsonian and Air & Space magazines. The British scientist James Smithson left most of his wealth to his nephew Henry James Hungerford, Congress officially accepted the legacy bequeathed to the nation, and pledged the faith of the United States to the charitable trust on July 1,1836. The American diplomat Richard Rush was dispatched to England by President Andrew Jackson to collect the bequest, Rush returned in August 1838 with 105 sacks containing 104,960 gold sovereigns. Once the money was in hand, eight years of Congressional haggling ensued over how to interpret Smithsons rather vague mandate for the increase, unfortunately, the money was invested by the US Treasury in bonds issued by the state of Arkansas which soon defaulted. The United States Exploring Expedition by the U. S. Navy circumnavigated the globe between 1838 and 1842, in 1846, the regents developed a plan for weather observation, in 1847, money was appropriated for meteorological research. The Institution became a magnet for young scientists from 1857 to 1866, the Smithsonian played a critical role as the U. S. partner institution in early bilateral scientific exchanges with the Academy of Sciences of Cuba. The Smithsonian Institution Building began construction in 1849, designed by architect James Renwick Jr. its interiors were completed by general contract Gilbert Cameron and the building opened in 1855. The Smithsonians first expansion came with construction of the Arts and Industries Building in 1881, Congress had promised to build a new structure for the museum if the 1876 Philadelphia Centennial Exposition generated enough income. It did, and the building was designed by architects Adolf Cluss and Paul Schulze, meigs of the United States Army Corps of Engineers. The National Zoological Park opened in 1889 to accommodate the Smithsonians Department of Living Animals and this structure was designed by the D. C. architectural firm of Hornblower & Marshall. More than 40 years would pass before the museum, the Museum of History. It was designed by the firm of McKim, Mead & White. That same year, the Smithsonian signed an agreement to take over the Cooper Union Museum for the Arts of Decoration, the National Portrait Gallery and the Smithsonian American Art Museum opened in the Old Patent Office Building on October 7,1968. The first new building to open since the National Museum of Natural History was the Hirshhorn Museum and Sculpture Garden
13.
World War II
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World War II, also known as the Second World War, was a global war that lasted from 1939 to 1945, although related conflicts began earlier. It involved the vast majority of the worlds countries—including all of the great powers—eventually forming two opposing alliances, the Allies and the Axis. It was the most widespread war in history, and directly involved more than 100 million people from over 30 countries. Marked by mass deaths of civilians, including the Holocaust and the bombing of industrial and population centres. These made World War II the deadliest conflict in human history, from late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, and formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Poland, Finland, Romania and the Baltic states. In December 1941, Japan attacked the United States and European colonies in the Pacific Ocean, and quickly conquered much of the Western Pacific. The Axis advance halted in 1942 when Japan lost the critical Battle of Midway, near Hawaii, in 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained all of its territorial losses and invaded Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in South Central China and Burma, while the Allies crippled the Japanese Navy, thus ended the war in Asia, cementing the total victory of the Allies. World War II altered the political alignment and social structure of the world, the United Nations was established to foster international co-operation and prevent future conflicts. The victorious great powers—the United States, the Soviet Union, China, the United Kingdom, the Soviet Union and the United States emerged as rival superpowers, setting the stage for the Cold War, which lasted for the next 46 years. Meanwhile, the influence of European great powers waned, while the decolonisation of Asia, most countries whose industries had been damaged moved towards economic recovery. Political integration, especially in Europe, emerged as an effort to end pre-war enmities, the start of the war in Europe is generally held to be 1 September 1939, beginning with the German invasion of Poland, Britain and France declared war on Germany two days later. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or even the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred simultaneously and this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935. The British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the forces of Mongolia and the Soviet Union from May to September 1939, the exact date of the wars end is also not universally agreed upon. It was generally accepted at the time that the war ended with the armistice of 14 August 1945, rather than the formal surrender of Japan
14.
Precipitation
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In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation include drizzle, rain, sleet, snow, graupel, Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, so that the water condenses and precipitates. Thus, fog and mist are not precipitation but suspensions, because the vapor does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated, Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers, moisture that is lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be condensed into clouds and rain. This process is active when freezing rain is occurring. A stationary front is often present near the area of freezing rain, provided necessary and sufficient atmospheric moisture content, the moisture within the rising air will condense into clouds, namely stratus and cumulonimbus. Eventually, the droplets will grow large enough to form raindrops. Lake-effect snowfall can be locally heavy, thundersnow is possible within a cyclones comma head and within lake effect precipitation bands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation, on the leeward side of mountains, desert climates can exist due to the dry air caused by compressional heating. The movement of the trough, or intertropical convergence zone. Precipitation is a component of the water cycle, and is responsible for depositing the fresh water on the planet. Approximately 505,000 cubic kilometres of water falls as precipitation each year,398,000 cubic kilometres of it over the oceans and 107,000 cubic kilometres over land. Given the Earths surface area, that means the globally averaged annual precipitation is 990 millimetres, Climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes. Precipitation may occur on celestial bodies, e. g. when it gets cold, Mars has precipitation which most likely takes the form of frost. Precipitation is a component of the water cycle, and is responsible for depositing most of the fresh water on the planet. Approximately 505,000 km3 of water falls as precipitation each year,398,000 km3 of it over the oceans, given the Earths surface area, that means the globally averaged annual precipitation is 990 millimetres. Mechanisms of producing precipitation include convective, stratiform, and orographic rainfall, Precipitation can be divided into three categories, based on whether it falls as liquid water, liquid water that freezes on contact with the surface, or ice
15.
High-pressure area
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A high-pressure area, high or anticyclone is a region where the atmospheric pressure at the surface of the planet is greater than its surrounding environment. Winds within high-pressure areas flow outward from the higher areas near their centers towards the lower pressure areas further from their centers. Viewed from above this twist in wind direction is in the direction as the rotation of the planet. The strongest high-pressure areas are associated with air masses which push away out of polar regions during the winter when there is less sun to warm neighboring regions. These Highs change character and weaken once they move further over relatively warmer water bodies, many of the features of Highs may be understood in context of middle- or meso-scale and relatively enduring dynamics of a planets atmospheric circulation. For example, massive atmospheric subsidences occur as part of the branches of Ferrel cells. Hadley cells help form the ridge, steer tropical waves. The subtropical ridge also helps form most of the worlds deserts, on English-language weather maps, high-pressure centers are identified by the letter H. Weather maps in other languages may use different letters or symbols. The direction of flow around an atmospheric high-pressure area and a low-pressure area, as seen from above. High-pressure systems rotate clockwise in the northern Hemisphere, low-pressure systems rotate counterclockwise in the southern hemisphere, the scientific terms in English used to describe the weather systems generated by highs and lows were introduced in the mid-1800s, mostly by the British. The scientific theories which explain the general phenomena originated about two centuries earlier, the term Cyclone was coined by Henry Piddington of the British East India Company to describe the devastating storm of December 1789 in Coringa, India. A cyclone forms around a low-pressure area, anticyclone, the term for the kind of weather around a high-pressure area, was coined in 1877 by Francis Galton to indicate an area whose winds revolved in the opposite direction of a cyclone. In British English, the direction of clockwise is referred to as anticlockwise. So, both the earth and winds around a low-pressure area rotate counter-clockwise in the hemisphere. The opposite to two cases occurs in the case of a high. These results derive from the Coriolis effect, that explains in detail the physics. High-pressure systems form due to motion through the troposphere, the atmospheric layer where weather occurs. Preferred areas within a flow pattern in higher levels of the troposphere are beneath the western side of troughs
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Low-pressure area
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A low-pressure area, low, or depression is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure systems form under areas of wind divergence that occur in the levels of the troposphere. The formation process of an area is known as cyclogenesis. Within the field of meteorology, atmospheric divergence aloft occurs in two areas, the first area is on the east side of upper troughs, which form half of a Rossby wave within the Westerlies. A second area of wind divergence aloft occurs ahead of embedded shortwave troughs, diverging winds aloft ahead of these troughs cause atmospheric lift within the troposphere below, which lowers surface pressures as upward motion partially counteracts the force of gravity. Thermal lows form due to localized heating caused by greater sunshine over deserts, since localized areas of warm air are less dense than their surroundings, this warmer air rises, which lowers atmospheric pressure near that portion of the Earths surface. Large-scale thermal lows over continents help drive monsoon circulations, low-pressure areas can also form due to organized thunderstorm activity over warm water. When this occurs over the tropics in concert with the Intertropical Convergence Zone, Monsoon troughs reach their northerly extent in August and their southerly extent in February. When a convective low acquires a well-hot circulation in the tropics it is termed a tropical cyclone, Tropical cyclones can form during any month of the year globally, but can occur in either the northern or southern hemisphere during November. Since clouds reflect sunlight, incoming solar radiation decreases, which causes lower temperatures during the day. At night the effect of clouds on outgoing longwave radiation, such as heat energy from the surface. The stronger the area of low pressure, the stronger the winds experienced in its vicinity, globally, low-pressure systems are most frequently located over the Tibetan Plateau and in the lee of the Rocky mountains. In Europe, recurring low-pressure weather systems are known as depressions. Cyclogenesis is the development and strengthening of cyclonic circulations, or low-pressure areas, cyclogenesis is the opposite of cyclolysis, and has an anticyclonic equivalent which deals with the formation of high-pressure areas—anticyclogenesis. Cyclogenesis is a term for several different processes, all of which result in the development of some sort of cyclone. Meteorologists use the term cyclone where circular pressure systems flow in the direction of the Earths rotation, the largest low-pressure systems are cold-core polar cyclones and extratropical cyclones which lie on the synoptic scale. Warm-core cyclones such as cyclones, mesocyclones, and polar lows lie within the smaller mesoscale. Subtropical cyclones are of intermediate size, cyclogenesis can occur at various scales, from the microscale to the synoptic scale
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History of surface weather analysis
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The history of surface weather analysis concerns the timetable of developments related to surface weather analysis. Initially a tool of study for the behavior of storms, surface weather analyses became a work in progress to explain current weather and as an aid for short term weather forecasting. Initial efforts to create surface weather analyses began in the century by using surface weather observations to analyze isobars, isotherms. By the mid-20th century, much information was being placed upon the station models plotted on weather maps and surface fronts. Eventually, observation plotting went from an exercise to an automated task for computers and plotters. Surface analysis remains a manual and partially subjective exercise, whether it be via hand and paper, the use of weather charts in a modern sense began in the middle portion of the 19th century. Weather map pioneers include William Charles Redfield, William Reid, Elias Loomis, and Sir Francis Galton, the invention of the telegraph in 1837 made it possible to gather weather information from multiple distant locations quickly enough to preserve its value for real-time applications. The Smithsonian Institution developed its network of observers over much of the central, beginning in 1849, the Smithsonian started producing surface analyses on a daily basis using the 150 stations in their network. The U. S. Army Signal Corps inherited this network between 1870 and 1874 by an act of Congress, and expanded it to the west coast soon afterwards. At first, all the data on the map was not taken at exactly the time in the early days of these analyses because of a lack of time standardization. The first attempts at time standardization took hold in the Great Britain by 1855, however, in the United States, standard time did not come to pass until 1883, when time zones started to come into use across America for railroad use. The entire United States did not finally come under the influence of time zones until 1905, a general indication of the weather for various cities around the country was also included on the bottom of the map. Within a short time, the Signal Corps added a tables showing eight-hour pressure change, 24-hour temperature change, relative humidity, the Signal Office also added a general discussion of synoptic weather features and forecast, before adding isobars and isotherms onto the maps. By the end of 1872, the maps had established the format it would use until the introduction of frontal analysis, internationally, other countries followed the lead of the United States, in regards to taking simultaneous weather observations, starting in 1873. Other countries then began preparing surface analyses, in Australia, the first weather map showed up in print media in 1877. Japans Tokyo Meteorological Observatory, the forerunner of the Japan Meteorological Agency, the London Times published the first weather map on April 1,1875. In the United States, the 1876 Centennial Exposition in Philadelphia, Pennsylvania demonstrated that daily weather map transmission via telegraph could be accomplished, the New York Daily Graphic published weather maps from mid-1879 through the summer of 1882. By 1894, there were four daily newspapers publishing weather maps in Boston, New Orleans, Cincinnati, and San Francisco
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Great Blizzard of 1888
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The Great Blizzard of 1888 or Great Blizzard of 88 was one of the most severe recorded blizzards in the history of the United States of America. The storm, referred to as the Great White Hurricane, paralyzed the East Coast from the Chesapeake Bay to Maine, railroads were shut down and people were confined to their houses for up to a week. Railway and telegraph lines were disabled, and this provided the impetus to move pieces of infrastructure underground. The weather preceding the blizzard was unseasonably mild with rains that turned to snow as temperatures dropped rapidly. The storm began in earnest shortly after midnight on March 12, and continued unabated for a full day and a half. The National Weather Service estimated this Noreaster dumped as much as 50 inches of snow in parts of Connecticut and Massachusetts, while parts of New Jersey, most of northern Vermont received from 20 inches to 30 inches in this storm. Drifts were reported to average 30–40 feet, over the tops of houses from New York to New England, the highest drift was recorded in Gravesend, New York. It was reported that 58 inches of snow fell in Saratoga Springs, New York,48 inches in Albany, New York,45 inches of snow in New Haven, Connecticut, and 22 inches of snow in New York City. New Yorks Central Park Observatory reported a temperature of 6 °F, and a daytime average of 9 °F on March 13. The New York Stock Exchange was closed for two days, similarly, telegraph infrastructure was disabled, isolating Montreal and most of the large northeastern U. S. cities from Washington, D. C. to Boston for days. Following the storm, New York began placing its telegraph and telephone infrastructure underground to prevent their destruction, fire stations were immobilized, and property loss from fire alone was estimated at $25 million. The blizzard resulted in the founding of the Christman Bird and Wildlife Sanctuary located near Delanson, Schenectady County, from Chesapeake Bay through the New England area, more than 200 ships were either grounded or wrecked, resulting in the deaths of at least 100 seamen. Severe flooding occurred after the due to melting snow, especially in the Brooklyn area. Efforts were made to push the snow into the Atlantic Ocean, more than 400 people died from the storm and the ensuing cold, including 200 in New York City alone. Edward Rutherfurds 2009 novel New York has a section set during the blizzard. In the HBO series Boardwalk Empires pilot episode, protagonist Nucky Thompson claims to have reduced to hunting rats to feed his family during the blizzard. This is quickly revealed to be a lie designed to gain sympathy votes, borgna Brunner, The Great White Hurricane Accessed April 17,2012 In a Blizzards Grasp. G. J. Christiano, The Blizzard of 1888, the Impact of this Devastating Storm on New York Transit Accessed April 17,2012 Martí, writing New York, a literary anthology
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Signal Corps (United States Army)
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The United States Army Signal Corps develops, tests, provides, and manages communications and information systems support for the command and control of combined arms forces. It was established in 1860, the brainchild of United States Army Major Albert J. Myer, support for the command and control of combined arms forces. Signal support includes Network Operations and management of the electromagnetic spectrum, while serving as a medical officer in Texas in 1856, Albert James Myer proposed that the Army use his visual communications system, called aerial telegraphy. When the Army adopted his system on 21 June 1860, the Signal Corps was born with Myer as the first, Major Myer first used his visual signaling system on active service in New Mexico during the early 1860s Navajo expedition. For nearly three years, Myer was forced to rely on detailed personnel, although he envisioned a separate, myers vision came true on 3 March 1863, when Congress authorized a regular Signal Corps for the duration of the war. Some 2,900 officers and enlisted men served, although not at any single time, even in the Civil War, the wigwag system, restricted to line-of-sight communications, was waning in the face of the electric telegraph. Initially, Myer used his office downtown in Washington, D. C. to house the Signal Corps School, when it was found to need additional space, he sought out other locations. First came Fort Greble, one of the Defenses of Washington during the Civil War, the size and location were outstanding. The school remained there for over 20 years and ultimately was renamed Fort Myer, Signal Corps detachments participated in campaigns fighting Native Americans in the west, such as the Powder River Expedition of 1865. The electric telegraph, in addition to signaling, became a Signal Corps responsibility in 1867. Within 12 years, the Corps had constructed, and was maintaining and operating, in 1870, the Signal Corps established a congressionally mandated national weather service. Within a decade, with the assistance of Lieutenant Adolphus Greely, Myer died in 1880, having attained the rank of brigadier general and the title of Chief Signal Officer. The weather bureau became part of the U. S. Department of Agriculture in 1891, the Signal Corps role in the Spanish–American War of 1898 and the subsequent Philippine Insurrection was on a grander scale than it had been in the Civil War. In 1908, on Fort Myer, Virginia, the Wright brothers made test flights of the Armys first airplane built to Signal Corps specifications, reflecting the need for an official pilot rating, War Department Bulletin No. 2, released on 24 February 1911, established a Military Aviator rating, Army aviation remained within the Signal Corps until 1918, when it became the Army Air Service. The Signal Corps lost no time in meeting the challenges of World War I, Chief Signal Officer George Owen Squier worked closely with private industry to perfect radio tubes while creating a major signal laboratory at Camp Alfred Vail. Early radiotelephones developed by the Signal Corps were introduced into the European theater in 1918, while the new American voice radios were superior to the radiotelegraph sets, telephone and telegraph remained the major technology of World War I. A pioneer in radar, Colonel William Blair, director of the Signal Corps laboratories at Fort Monmouth, even before the United States entered World War II, mass production of two radar sets, the SCR-268 and the SCR-270, had begun
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Detroit
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Detroit is the most populous city in the U. S. state of Michigan, the fourth-largest city in the Midwest and the largest city on the United States–Canada border. It is the seat of Wayne County, the most populous county in the state, the municipality of Detroit had a 2015 estimated population of 677,116, making it the 21st-most populous city in the United States. Roughly one-half of Michigans population lives in Metro Detroit alone, the Detroit–Windsor area, a commercial link straddling the Canada–U. S. Border, has a population of about 5.7 million. Detroit is a port on the Detroit River, a strait that connects the Great Lakes system to the Saint Lawrence Seaway. The Detroit Metropolitan Airport is among the most important hubs in the United States, the City of Detroit anchors the second-largest economic region in the Midwest, behind Chicago, and the thirteenth-largest in the United States. Detroit and its neighboring Canadian city Windsor are connected through a tunnel and various bridges, Detroit was founded on July 24,1701 by the French explorer and adventurer Antoine de la Mothe Cadillac and a party of settlers. During the 19th century, it became an important industrial hub at the center of the Great Lakes region, with expansion of the American automobile industry in the early 20th century, the Detroit area emerged as a significant metropolitan region within the United States. The city became the fourth-largest in the country for a period, in the 1950s and 1960s, suburban expansion continued with construction of a regional freeway system. A great portion of Detroits public transport was abandoned in favour of becoming a city in the post-war period. Due to industrial restructuring and loss of jobs in the auto industry, between 2000 and 2010 the citys population fell by 25 percent, changing its ranking from the nations 10th-largest city to 18th. In 2010, the city had a population of 713,777 and this resulted from suburbanization, corruption, industrial restructuring and the decline of Detroits auto industry. In 2013, the state of Michigan declared an emergency for the city. Detroit has experienced urban decay as its population and jobs have shifted to its suburbs or elsewhere, conservation efforts managed to save many architectural pieces since the 2000s and allowed several large-scale revitalisations. More recently, the population of Downtown Detroit, Midtown Detroit, paleo-Indian people inhabited areas near Detroit as early as 11,000 years ago. In the 17th century, the region was inhabited by Huron, Odawa, Potawatomi, for the next hundred years, virtually no British, colonist, or French action was contemplated without consultation with, or consideration of the Iroquois likely response. When the French and Indian War evicted the Kingdom of France from Canada, the 1798 raids and resultant 1799 decisive Sullivan Expedition reopened the Ohio Country to westward emigration, which began almost immediately, and by 1800 white settlers were pouring westwards. By 1773, the population of Detroit was 1,400, by 1778, its population was up to 2,144 and it was the third-largest city in the Province of Quebec
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Front (military)
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A military front or battlefront is a contested armed frontier between opposing forces. It can be a local or tactical front, or it can range to a theater, a typical front was the Western Front in France and Belgium in World War I. The term home front has been used to denote conditions in the sector of a country at war. Both the Soviet and Polish Armies used the front to mean an army group during the Polish-Soviet War. The equivalent of the established in the header was the Theater of military operations. The term front line city was used by the Germans during their retreat from Moscow/Stalingrad to refer to metropolitan centres that had become disputed by the two combatants. Designation of a city as such resulted in administrative changes, in the film Downfall, the term was briefly referenced. The term transferred to the front is used by soldiers or personnel when their position has been changed from other activities
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World War I
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World War I, also known as the First World War, the Great War, or the War to End All Wars, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. More than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history and it was one of the deadliest conflicts in history, and paved the way for major political changes, including revolutions in many of the nations involved. The war drew in all the worlds great powers, assembled in two opposing alliances, the Allies versus the Central Powers of Germany and Austria-Hungary. These alliances were reorganised and expanded as more nations entered the war, Italy, Japan, the trigger for the war was the assassination of Archduke Franz Ferdinand of Austria, heir to the throne of Austria-Hungary, by Yugoslav nationalist Gavrilo Princip in Sarajevo on 28 June 1914. This set off a crisis when Austria-Hungary delivered an ultimatum to the Kingdom of Serbia. Within weeks, the powers were at war and the conflict soon spread around the world. On 25 July Russia began mobilisation and on 28 July, the Austro-Hungarians declared war on Serbia, Germany presented an ultimatum to Russia to demobilise, and when this was refused, declared war on Russia on 1 August. Germany then invaded neutral Belgium and Luxembourg before moving towards France, after the German march on Paris was halted, what became known as the Western Front settled into a battle of attrition, with a trench line that changed little until 1917. On the Eastern Front, the Russian army was successful against the Austro-Hungarians, in November 1914, the Ottoman Empire joined the Central Powers, opening fronts in the Caucasus, Mesopotamia and the Sinai. In 1915, Italy joined the Allies and Bulgaria joined the Central Powers, Romania joined the Allies in 1916, after a stunning German offensive along the Western Front in the spring of 1918, the Allies rallied and drove back the Germans in a series of successful offensives. By the end of the war or soon after, the German Empire, Russian Empire, Austro-Hungarian Empire, national borders were redrawn, with several independent nations restored or created, and Germanys colonies were parceled out among the victors. During the Paris Peace Conference of 1919, the Big Four imposed their terms in a series of treaties, the League of Nations was formed with the aim of preventing any repetition of such a conflict. This effort failed, and economic depression, renewed nationalism, weakened successor states, and feelings of humiliation eventually contributed to World War II. From the time of its start until the approach of World War II, at the time, it was also sometimes called the war to end war or the war to end all wars due to its then-unparalleled scale and devastation. In Canada, Macleans magazine in October 1914 wrote, Some wars name themselves, during the interwar period, the war was most often called the World War and the Great War in English-speaking countries. Will become the first world war in the sense of the word. These began in 1815, with the Holy Alliance between Prussia, Russia, and Austria, when Germany was united in 1871, Prussia became part of the new German nation. Soon after, in October 1873, German Chancellor Otto von Bismarck negotiated the League of the Three Emperors between the monarchs of Austria-Hungary, Russia and Germany
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Cyclone
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In meteorology, a cyclone is a large scale air mass that rotates around a strong center of low atmospheric pressure. A cyclone differs from a hurricane or typhoon only on the basis of location, a hurricane is a storm that occurs in the Atlantic Ocean and northeastern Pacific Ocean, a typhoon occurs in the northwestern Pacific Ocean, and a cyclone occurs in the south Pacific or Indian Ocean. Cyclones are characterized by inward spiraling winds that rotate about a zone of low pressure, the largest low-pressure systems are polar vortices and extratropical cyclones of the largest scale. Warm-core cyclones such as cyclones and subtropical cyclones also lie within the synoptic scale. Mesocyclones, tornadoes and dust devils lie within the smaller mesoscale, Upper level cyclones can exist without the presence of a surface low, and can pinch off from the base of the Tropical Upper Tropospheric Trough during the summer months in the Northern Hemisphere. Cyclones have also seen on extraterrestrial planets, such as Mars. Cyclogenesis describes the process of formation and intensification. Extratropical cyclones begin as waves in large regions of enhanced mid-latitude temperature contrasts called baroclinic zones and these zones contract and form weather fronts as the cyclonic circulation closes and intensifies. Later in their cycle, extratropical cyclones occlude as cold air masses undercut the warmer air. A cyclones track is guided over the course of its 2 to 6 day life cycle by the flow of the subtropical jet stream. Weather fronts mark the boundary between two masses of air of different temperature, humidity, and densities, and are associated with the most prominent meteorological phenomena. Strong cold fronts typically feature narrow bands of thunderstorms and severe weather, such fronts form west of the circulation center and generally move from west to east, warm fronts form east of the cyclone center and are usually preceded by stratiform precipitation and fog. Warm fronts move poleward ahead of the cyclone path, occluded fronts form late in the cyclone life cycle near the center of the cyclone and often wrap around the storm center. Tropical cyclogenesis describes the process of development of tropical cyclones, Tropical cyclones form due to latent heat driven by significant thunderstorm activity, and are warm core. Cyclones can transition between extratropical, subtropical, and tropical phases, mesocyclones form as warm core cyclones over land, and can lead to tornado formation. Waterspouts can also form from mesocyclones, but more often develop from environments of high instability, henry Piddington published almost 40 papers dealing with tropical storms from Calcutta between 1835 and 1855 in The Journal of the Asiatic Society. He also coined the term cyclone, meaning the coil of a snake, in 1842, he published his landmark thesis, Laws of the Storms. There are a number of characteristics common to all cyclones
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Washington, D.C.
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Washington, D. C. formally the District of Columbia and commonly referred to as Washington, the District, or simply D. C. is the capital of the United States. The signing of the Residence Act on July 16,1790, Constitution provided for a federal district under the exclusive jurisdiction of the Congress and the District is therefore not a part of any state. The states of Maryland and Virginia each donated land to form the federal district, named in honor of President George Washington, the City of Washington was founded in 1791 to serve as the new national capital. In 1846, Congress returned the land ceded by Virginia, in 1871. Washington had an population of 681,170 as of July 2016. Commuters from the surrounding Maryland and Virginia suburbs raise the population to more than one million during the workweek. The Washington metropolitan area, of which the District is a part, has a population of over 6 million, the centers of all three branches of the federal government of the United States are in the District, including the Congress, President, and Supreme Court. Washington is home to national monuments and museums, which are primarily situated on or around the National Mall. The city hosts 176 foreign embassies as well as the headquarters of international organizations, trade unions, non-profit organizations, lobbying groups. A locally elected mayor and a 13‑member council have governed the District since 1973, However, the Congress maintains supreme authority over the city and may overturn local laws. D. C. residents elect a non-voting, at-large congressional delegate to the House of Representatives, the District receives three electoral votes in presidential elections as permitted by the Twenty-third Amendment to the United States Constitution, ratified in 1961. Various tribes of the Algonquian-speaking Piscataway people inhabited the lands around the Potomac River when Europeans first visited the area in the early 17th century, One group known as the Nacotchtank maintained settlements around the Anacostia River within the present-day District of Columbia. Conflicts with European colonists and neighboring tribes forced the relocation of the Piscataway people, some of whom established a new settlement in 1699 near Point of Rocks, Maryland. 43, published January 23,1788, James Madison argued that the new government would need authority over a national capital to provide for its own maintenance. Five years earlier, a band of unpaid soldiers besieged Congress while its members were meeting in Philadelphia, known as the Pennsylvania Mutiny of 1783, the event emphasized the need for the national government not to rely on any state for its own security. However, the Constitution does not specify a location for the capital, on July 9,1790, Congress passed the Residence Act, which approved the creation of a national capital on the Potomac River. The exact location was to be selected by President George Washington, formed from land donated by the states of Maryland and Virginia, the initial shape of the federal district was a square measuring 10 miles on each side, totaling 100 square miles. Two pre-existing settlements were included in the territory, the port of Georgetown, Maryland, founded in 1751, many of the stones are still standing
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Hong Kong
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Hong Kong, officially the Hong Kong Special Administrative Region of the Peoples Republic of China, is an autonomous territory on the Pearl River Delta of East Asia. Macau lies across the delta to the west, and the Chinese province of Guangdong borders the territory to the north. With a total area of 1,106 square kilometres. Hong Kong was later occupied by Japan during World War II until British control resumed in 1945, under the principle of one country, two systems, Hong Kong maintains a separate political and economic system from China. Except in military defence and foreign affairs, Hong Kong maintains its independent executive, legislative, in addition, Hong Kong develops relations directly with foreign states and international organisations in a broad range of appropriate fields. Hong Kong is one of the worlds most significant financial centres, with the highest Financial Development Index score and consistently ranks as the worlds most competitive and freest economic entity. As the worlds 8th largest trading entity, its legal tender, Hong Kongs tertiary sector dominated economy is characterised by simple taxation with a competitive level of corporate tax and supported by its independent judiciary system. However, while Hong Kong has one of the highest per capita incomes in the world and it has a very high Human Development Index ranking and the worlds longest life expectancy. Over 90% of the population use of well-developed public transportation. Seasonal air pollution with origins from neighbouring areas of Mainland China. Hong Kong was officially recorded in the 1842 Treaty of Nanking to encompass the entirety of the island, before 1842, the name referred to a small inlet—now Aberdeen Harbour, literally means Little Hong Kong)—between Aberdeen Island and the southern coast of Hong Kong Island. Aberdeen was a point of contact between British sailors and local fishermen. Detailed and accurate romanisation systems for Cantonese were available and in use at the time, fragrance may refer to the sweet taste of the harbours fresh water estuarine influx of the Pearl River or to the incense from factories lining the coast of northern Kowloon. The incense was stored near Aberdeen Harbour for export before Hong Kong developed Victoria Harbour, the name had often been written as the single word Hongkong until the government adopted the current form in 1926. Nevertheless, a number of century-old institutions still retain the form, such as the Hongkong Post, Hongkong Electric. As of 1997, its name is the Hong Kong Special Administrative Region of the Peoples Republic of China. This is the title as mentioned in the Hong Kong Basic Law. Hong Kong has carried many nicknames, the most famous among those is the Pearl of the Orient, which reflected the impressive nightscape of the citys light decorations on the skyscrapers along both sides of the Victoria Harbour
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Advanced Weather Interactive Processing System
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Weather forecasters utilize the capabilities of AWIPS to make increasingly accurate weather, water, and climate predictions, and to dispense rapid, highly reliable warnings and advisories. The AWIPS system architectural design is driven by expandability, flexibility, availability, the system is easily expandable to allow for the introduction of new functionality and the augmentation of network and processing capabilities. AWIPS is designed so that software and data can be migrated to new platforms as technology evolves, AWIPS replaced the Automation of Field Operations and Services system which had become obsolete and was very difficult to maintain. AWIPS was originally developed and maintained by PRC, Inc with installation completed in 1998, since 2005, Raytheon has been NWS’ partner for the operations, maintenance and evolution of AWIPS, providing the integrated mission services required to sustain and enhance system performance. It is a contract with five one-year award terms for a potential maximum 10-year contract. Teaming with Raytheon are Keane Federal Systems, Globecomm Systems Inc, ENSCO, Reston Consulting Group, Fairfield Technologies, and Earth Resources Technology. As the architect of the AWIPS evolution, Raytheon designed, developed, AWIPS II, which features a new service oriented architecture began roll-out in late 2011. This new system simplified code and consequently strengthened system performance while reducing the maintenance burden, all of this is achieved while retaining a system look and feel that makes the AWIPS evolution appear similar to the user. First Warning, a computer-based alerting system used to disseminate watches, warnings and advisories via broadcast television
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Meteorology
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Meteorology is a branch of the atmospheric sciences which includes atmospheric chemistry and atmospheric physics, with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not occur until the 18th century, the 19th century saw modest progress in the field after weather observation networks were formed across broad regions. Prior attempts at prediction of weather depended on historical data, Meteorological phenomena are observable weather events that are explained by the science of meteorology. Different spatial scales are used to describe and predict weather on local, regional, Meteorology, climatology, atmospheric physics, and atmospheric chemistry are sub-disciplines of the atmospheric sciences. Meteorology and hydrology compose the interdisciplinary field of hydrometeorology, the interactions between Earths atmosphere and its oceans are part of a coupled ocean-atmosphere system. Meteorology has application in diverse fields such as the military, energy production, transport, agriculture. The word meteorology is from Greek μετέωρος metéōros lofty, high and -λογία -logia -logy, varāhamihiras classical work Brihatsamhita, written about 500 AD, provides clear evidence that a deep knowledge of atmospheric processes existed even in those times. In 350 BC, Aristotle wrote Meteorology, Aristotle is considered the founder of meteorology. One of the most impressive achievements described in the Meteorology is the description of what is now known as the hydrologic cycle and they are all called swooping bolts because they swoop down upon the Earth. Lightning is sometimes smoky, and is then called smoldering lightning, sometimes it darts quickly along, at other times, it travels in crooked lines, and is called forked lightning. When it swoops down upon some object it is called swooping lightning, the Greek scientist Theophrastus compiled a book on weather forecasting, called the Book of Signs. The work of Theophrastus remained a dominant influence in the study of weather, in 25 AD, Pomponius Mela, a geographer for the Roman Empire, formalized the climatic zone system. According to Toufic Fahd, around the 9th century, Al-Dinawari wrote the Kitab al-Nabat, ptolemy wrote on the atmospheric refraction of light in the context of astronomical observations. St. Roger Bacon was the first to calculate the size of the rainbow. He stated that a rainbow summit can not appear higher than 42 degrees above the horizon, in the late 13th century and early 14th century, Kamāl al-Dīn al-Fārisī and Theodoric of Freiberg were the first to give the correct explanations for the primary rainbow phenomenon. Theoderic went further and also explained the secondary rainbow, in 1716, Edmund Halley suggested that aurorae are caused by magnetic effluvia moving along the Earths magnetic field lines. In 1441, King Sejongs son, Prince Munjong, invented the first standardized rain gauge and these were sent throughout the Joseon Dynasty of Korea as an official tool to assess land taxes based upon a farmers potential harvest. In 1450, Leone Battista Alberti developed a swinging-plate anemometer, and was known as the first anemometer, in 1607, Galileo Galilei constructed a thermoscope
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Geographic information system
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A geographic information system is a system designed to capture, store, manipulate, analyze, manage, and present spatial or geographic data. What goes beyond a GIS is a spatial data infrastructure, a concept that has no such restrictive boundaries, in general, the term describes any information system that integrates, stores, edits, analyzes, shares, and displays geographic information. GIS applications are tools that allow users to create interactive queries, analyze spatial information, edit data in maps, Geographic information science is the science underlying geographic concepts, applications, and systems. GIS is a term that can refer to a number of different technologies, processes. It is attached to operations and has many applications related to engineering, planning, management, transport/logistics, insurance, telecommunications. For that reason, GIS and location intelligence applications can be the foundation for many location-enabled services that rely on analysis, GIS can relate unrelated information by using location as the key index variable. Locations or extents in the Earth space–time may be recorded as dates/times of occurrence, and x, y, and z coordinates representing, longitude, latitude, all Earth-based spatial–temporal location and extent references should be relatable to one another and ultimately to a real physical location or extent. This key characteristic of GIS has begun to open new avenues of scientific inquiry, the first known use of the term geographic information system was by Roger Tomlinson in the year 1968 in his paper A Geographic Information System for Regional Planning. Tomlinson is also acknowledged as the father of GIS, previously, one of the first applications of spatial analysis in epidemiology is the 1832 Rapport sur la marche et les effets du choléra dans Paris et le département de la Seine. The French geographer Charles Picquet represented the 48 districts of the city of Paris by halftone color gradient according to the number of deaths by cholera per 1,000 inhabitants and this was one of the earliest successful uses of a geographic methodology in epidemiology. The early 20th century saw the development of photozincography, which allowed maps to be split into layers, for one layer for vegetation. This work was drawn on glass plates but later plastic film was introduced, with the advantages of being lighter, using less storage space and being less brittle. When all the layers were finished, they were combined into one using a large process camera. Once color printing came in, the idea was also used for creating separate printing plates for each color. Computer hardware development spurred by nuclear weapon research led to general-purpose computer mapping applications by the early 1960s, the year 1960 saw the development of the worlds first true operational GIS in Ottawa, Ontario, Canada by the federal Department of Forestry and Rural Development. A rating classification factor was added to permit analysis. CGIS was an improvement over computer mapping applications as it provided capabilities for overlay, measurement and it supported a national coordinate system that spanned the continent, coded lines as arcs having a true embedded topology and it stored the attribute and locational information in separate files. As a result of this, Tomlinson has become known as the father of GIS, CGIS lasted into the 1990s and built a large digital land resource database in Canada
29.
Station model
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In meteorology, station models are symbolic illustrations showing the weather occurring at a given reporting station. Meteorologists created the model to fit a number of weather elements into a small space on weather maps. This allows map users to analyze patterns in atmospheric pressure, temperature, wind speed & direction, cloud cover, precipitation, the most common station plots depict surface weather observations although upper air plots at various mandatory levels are also frequently depicted. Station model plots use an internationally accepted coding convention that has changed little since August 1,1941, elements in the plot show the key weather elements, including temperature, dew point, wind, cloud cover, air pressure, pressure tendency, and precipitation. Weather maps primarily use the model to show surface weather conditions. Station model plots use a mixture of metric and Imperial units depending on the maps location, surface maps in the United States primarily use Imperial units, such as inches, degrees Fahrenheit, and knots. Most of the world, however, uses metric measurements for everything but wind speed, the station model uses a wind barb to show both wind direction and speed. The wind barb shows the speed using flags on the end, Each half of a flag depicts 5 kn Each full flag depicts 10 kn Each pennant depicts 50 kn Winds are depicted as blowing from the direction the flags are facing. Therefore, a northeast wind will be depicted with an extending from the cloud circle to the northeast. Once plotted on a map, an analysis of isotachs can be accomplished, isotachs are particularly useful in diagnosing the location of the jet stream on upper level constant pressure charts, usually at or above the 300 hPa level. The flags and pennants point to the low pressure, so it is possible to determine at which hemisphere the station is standing. The barbs in the figure at the right are located at the Northern Hemisphere, more than a century ago, winds were initially plotted as arrows facing downwind, with feathers on both sides of the staff to indicate wind speed. In the United States, the change to the convention of flags shown on one side of the staff to indicate wind speed took effect on August 1,1941. Along with wind direction, cloud cover is one of the oldest atmospheric conditions to be coded on a station model, the circle in the middle of the station model represents cloud cover. In the United Kingdom, when the observation is taken from a weather observation site. If the shape is completely filled in, it is overcast, if conditions are completely clear, the circle or triangle is empty. If conditions are partly cloudy, the circle or triangle is partially filled in, the cloud cover shape has different looks depending upon how many oktas are covered by cloud. A sky half full of clouds would have a circle that was half white, below the shape indicating sky cover, the station model can indicate the coverage of low clouds, in oktas, and the ceiling height in hundreds of feet
30.
Wind
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Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the movement of air. Winds are commonly classified by their scale, their speed, the types of forces that cause them, the regions in which they occur. The strongest observed winds on a planet in the Solar System occur on Neptune, Winds have various aspects, an important one being its velocity, another the density of the gas involved, another its energy content or wind energy. In meteorology, winds are referred to according to their strength. Short bursts of high speed wind are termed gusts, strong winds of intermediate duration are termed squalls. Long-duration winds have various names associated with their strength, such as breeze, gale, storm. The two main causes of large-scale atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet, within the tropics, thermal low circulations over terrain and high plateaus can drive monsoon circulations. In coastal areas the sea breeze/land breeze cycle can define local winds, in areas that have variable terrain, mountain, Wind powers the voyages of sailing ships across Earths oceans. Hot air balloons use the wind to take trips, and powered flight uses it to increase lift. Areas of wind caused by various weather phenomena can lead to dangerous situations for aircraft. When winds become strong, trees and man-made structures are damaged or destroyed, Winds can shape landforms, via a variety of aeolian processes such as the formation of fertile soils, such as loess, and by erosion. Wind also affects the spread of wildfires, Winds can disperse seeds from various plants, enabling the survival and dispersal of those plant species, as well as flying insect populations. When combined with temperatures, wind has a negative impact on livestock. Wind affects animals food stores, as well as their hunting, Wind is caused by differences in the atmospheric pressure. When a difference in atmospheric pressure exists, air moves from the higher to the pressure area. On a rotating planet, air will also be deflected by the Coriolis effect, globally, the two major driving factors of large-scale wind patterns are the differential heating between the equator and the poles and the rotation of the planet. Outside the tropics and aloft from frictional effects of the surface, near the Earths surface, friction causes the wind to be slower than it would be otherwise
31.
Wind speed
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Wind speed, or wind flow velocity, is a fundamental atmospheric quantity. Wind speed is caused by air moving from high pressure to low pressure, Wind speed affects weather forecasting, aircraft and maritime operations, construction projects, growth and metabolism rate of many plant species, and countless other implications. Wind speed is now commonly measured with an anemometer but can also be classified using the older Beaufort scale which is based on observation of specifically defined wind effects. Wind speed is affected by a number of factors and situations and these include the pressure gradient, Rossby waves and jet streams, and local weather conditions. There are also links to be found between wind speed and wind direction, notably with the gradient and terrain conditions. Pressure gradient is a term to describe the difference in air pressure between two points in the atmosphere or on the surface of the Earth and it is vital to wind speed, because the greater the difference in pressure, the faster the wind flows to balance out the variation. The pressure gradient, when combined with the Coriolis effect and friction, Rossby waves are strong winds in the upper troposphere. These operate on a scale and move from West to East. The Rossby waves are themselves a different wind speed from what we experience in the lower troposphere, the wind gust was evaluated by the WMO Evaluation Panel who found that the anemometer was mechanically sound and the gust was within statistical probability and ratified the measurement in 2010. The anemometer was mounted 10 m above ground level, the pattern and scales of the gusts suggest that a mesovortex was embedded in the already strong eyewall of the cyclone. The now second highest surface wind speed ever recorded is 372 km/h at the Mount Washington Observatory,6,288 ft above sea level in the US on 12 April 1934. The anemometer, specifically designed for use on Mount Washington was later tested by the US National Weather Bureau, Wind speeds within certain atmospheric phenomena may greatly exceed these values but have never been accurately measured. Directly measuring these tornadic winds is rarely done as the violent wind would destroy the instruments, another method of estimating is to use Doppler on Wheels to sense the wind speeds remotely. The figure of 486 km/h during the 1999 Bridge Creek–Moore tornado in Oklahoma on 3 May 1999 is often quoted as the surface wind speed. However, another figure of 512 kilometres per hour has also quoted for the same tornado. Yet another number used by the Center for Severe Weather Research for that measurement is 486 ±32 km/h, however, speeds measured by Doppler radar are not considered official records. Wind speed is a factor in the design of structures. It is often the governing factor in the required strength of a structures design
32.
Wind direction
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Wind direction is reported by the direction from which it originates. For example, a wind blows from the north to the south. Wind direction is reported in cardinal directions or in azimuth degrees. Wind direction is measured in degrees clockwise from due north and so a wind coming from the south has a direction of 180 degrees. A variety of instruments can be used to wind direction, such as the windsock. Both of these work by moving to minimize air resistance. The way a weather vane is pointed by prevailing winds indicates the direction from which the wind is blowing. The larger opening of a windsock faces the direction that the wind is blowing from, its tail, with the smaller opening, modern instruments used to measure wind speed and direction are called anemometers and wind vanes, respectively. These types of instruments are used by the energy industry. In situations where modern instruments are not available, a finger can be used to test the direction of wind. This is accomplished by wetting the finger and pointing it upwards, the side of the finger that feels cool is the direction from which the wind is blowing. The same principle is used to measure the dew point using a sling psychrometer, another primitive technique for measuring wind direction is to take a pinch of grass and drop it, the direction that the grass falls is the direction the wind is blowing. This last technique is used by golfers because it allows them to gauge the strength of the wind as well. Yamartino method for calculating the standard deviation of wind direction Apparent wind Weather vane Wind power Air masses
33.
Overcast
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Overcast or overcast weather, as defined by the World Meteorological Organization, is the meteorological condition of clouds obscuring all of the sky by at least 95 percent. However, the sky cover must not be entirely due to surface-based obscuring phenomena such as fog. Overcast, written as OVC in the METAR observation, is reported when the cover is observed to equal eight oktas. An overcast sky may be identified as thin but otherwise is considered opaque which always constitutes a ceiling in aviation meteorology. Sometimes clouds can be different colors such as black or white, in some cases, it can be impossible to see distinct borders of clouds or the sky may be covered by a single type of cloud, such as stratus and the whole sky will be a dull white. Periods of overcast weather can range from a few hours to several days, overcast weather can also affect people suffering from seasonal affective disorder. The same weather, when observed from above, might be referred to as undercast
34.
Celsius
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Celsius, also known as centigrade, is a metric scale and unit of measurement for temperature. As an SI derived unit, it is used by most countries in the world and it is named after the Swedish astronomer Anders Celsius, who developed a similar temperature scale. The degree Celsius can refer to a temperature on the Celsius scale as well as a unit to indicate a temperature interval. Before being renamed to honour Anders Celsius in 1948, the unit was called centigrade, from the Latin centum, which means 100, and gradus, which means steps. The scale is based on 0° for the point of water. This scale is widely taught in schools today, by international agreement the unit degree Celsius and the Celsius scale are currently defined by two different temperatures, absolute zero, and the triple point of VSMOW. This definition also precisely relates the Celsius scale to the Kelvin scale, absolute zero, the lowest temperature possible, is defined as being precisely 0 K and −273.15 °C. The temperature of the point of water is defined as precisely 273.16 K at 611.657 pascals pressure. This definition fixes the magnitude of both the degree Celsius and the kelvin as precisely 1 part in 273.16 of the difference between absolute zero and the point of water. Thus, it sets the magnitude of one degree Celsius and that of one kelvin as exactly the same, additionally, it establishes the difference between the two scales null points as being precisely 273.15 degrees. In his paper Observations of two persistent degrees on a thermometer, he recounted his experiments showing that the point of ice is essentially unaffected by pressure. He also determined with precision how the boiling point of water varied as a function of atmospheric pressure. He proposed that the point of his temperature scale, being the boiling point. This pressure is known as one standard atmosphere, the BIPMs 10th General Conference on Weights and Measures later defined one standard atmosphere to equal precisely 1013250dynes per square centimetre. On 19 May 1743 he published the design of a mercury thermometer, in 1744, coincident with the death of Anders Celsius, the Swedish botanist Carolus Linnaeus reversed Celsiuss scale. In it, Linnaeus recounted the temperatures inside the orangery at the University of Uppsala Botanical Garden, since the 19th century, the scientific and thermometry communities worldwide referred to this scale as the centigrade scale. Temperatures on the scale were often reported simply as degrees or. More properly, what was defined as centigrade then would now be hectograde.2 gradians, for scientific use, Celsius is the term usually used, with centigrade otherwise continuing to be in common but decreasing use, especially in informal contexts in English-speaking countries
35.
Inch
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The inch is a unit of length in the imperial and United States customary systems of measurement now formally equal to 1⁄36 yard but usually understood as 1⁄12 of a foot. Derived from the Roman uncia, inch is also used to translate related units in other measurement systems. The English word inch was a borrowing from Latin uncia not present in other Germanic languages. The vowel change from Latin /u/ to English /ɪ/ is known as umlaut, the consonant change from the Latin /k/ to English /tʃ/ or /ʃ/ is palatalisation. Both were features of Old English phonology, inch is cognate with ounce, whose separate pronunciation and spelling reflect its reborrowing in Middle English from Anglo-Norman unce and ounce. In many other European languages, the word for inch is the same as or derived from the word for thumb, the inch is a commonly used customary unit of length in the United States, Canada, and the United Kingdom. It is also used in Japan for electronic parts, especially display screens, for example, three feet two inches can be written as 3′ 2″. Paragraph LXVII sets out the fine for wounds of various depths, one inch, one shilling, an Anglo-Saxon unit of length was the barleycorn. After 1066,1 inch was equal to 3 barleycorns, which continued to be its legal definition for several centuries, similar definitions are recorded in both English and Welsh medieval law tracts. One, dating from the first half of the 10th century, is contained in the Laws of Hywel Dda which superseded those of Dyfnwal, both definitions, as recorded in Ancient Laws and Institutes of Wales, are that three lengths of a barleycorn is the inch. However, the oldest surviving manuscripts date from the early 14th century, john Bouvier similarly recorded in his 1843 law dictionary that the barleycorn was the fundamental measure. He noted that this process would not perfectly recover the standard, before the adoption of the international yard and pound, various definitions were in use. In the United Kingdom and most countries of the British Commonwealth, the United States adopted the conversion factor 1 metre =39.37 inches by an act in 1866. In 1930, the British Standards Institution adopted an inch of exactly 25.4 mm, the American Standards Association followed suit in 1933. By 1935, industry in 16 countries had adopted the industrial inch as it came to be known, in 1946, the Commonwealth Science Congress recommended a yard of exactly 0.9144 metres for adoption throughout the British Commonwealth. This was adopted by Canada in 1951, the United States on 1 July 1959, Australia in 1961, effective 1 January 1964, and the United Kingdom in 1963, effective on 1 January 1964. The new standards gave an inch of exactly 25.4 mm,1.7 millionths of a longer than the old imperial inch and 2 millionths of an inch shorter than the old US inch. The United States retains the 1/39. 37-metre definition for survey purposes and this is approximately 1/8-inch in a mile
36.
Contour line
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A contour line of a function of two variables is a curve along which the function has a constant value. It is a cross-section of the graph of the function f parallel to the x, y plane. In cartography, a contour line joins points of elevation above a given level. A contour map is a map illustrated with contour lines, for example a map, which thus shows valleys and hills. The contour interval of a map is the difference in elevation between successive contour lines. More generally, a line for a function of two variables is a curve connecting points where the function has the same particular value. The gradient of the function is always perpendicular to the contour lines, when the lines are close together the magnitude of the gradient is large, the variation is steep. A level set is a generalization of a line for functions of any number of variables. Contour lines are curved, straight or a mixture of lines on a map describing the intersection of a real or hypothetical surface with one or more horizontal planes. The configuration of these contours allows map readers to infer relative gradient of a parameter, in the latter case, the method of interpolation affects the reliability of individual isolines and their portrayal of slope, pits and peaks. Contour lines are given specific names beginning iso- according to the nature of the variable being mapped. Specific names are most common in meteorology, where multiple maps with different variables may be viewed simultaneously, the prefix iso- can be replaced with isallo- to specify a contour line connecting points where a variable changes at the same rate during a given time period. The words isoline and isarithm are general terms covering all types of contour line, an isogon is a contour line for a variable which measures direction. In meteorology and in geomagnetics, the term isogon has specific meanings which are described below, an isocline is a line joining points with equal slope. In population dynamics and in geomagnetics, the terms isocline and isoclinic line have specific meanings which are described below, equidistant is a line of equal distance from a given point, line, polyline. In geography, the word isopleth is used for lines that depict a variable which cannot be measured at a point. An example is population density, which can be calculated by dividing the population of a district by the surface area of that district. Each calculated value is presumed to be the value of the variable at the centre of the area, the idea of an isopleth map can be compared with that of a choropleth map
37.
Isotach
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A contour line of a function of two variables is a curve along which the function has a constant value. It is a cross-section of the graph of the function f parallel to the x, y plane. In cartography, a contour line joins points of elevation above a given level. A contour map is a map illustrated with contour lines, for example a map, which thus shows valleys and hills. The contour interval of a map is the difference in elevation between successive contour lines. More generally, a line for a function of two variables is a curve connecting points where the function has the same particular value. The gradient of the function is always perpendicular to the contour lines, when the lines are close together the magnitude of the gradient is large, the variation is steep. A level set is a generalization of a line for functions of any number of variables. Contour lines are curved, straight or a mixture of lines on a map describing the intersection of a real or hypothetical surface with one or more horizontal planes. The configuration of these contours allows map readers to infer relative gradient of a parameter, in the latter case, the method of interpolation affects the reliability of individual isolines and their portrayal of slope, pits and peaks. Contour lines are given specific names beginning iso- according to the nature of the variable being mapped. Specific names are most common in meteorology, where multiple maps with different variables may be viewed simultaneously, the prefix iso- can be replaced with isallo- to specify a contour line connecting points where a variable changes at the same rate during a given time period. The words isoline and isarithm are general terms covering all types of contour line, an isogon is a contour line for a variable which measures direction. In meteorology and in geomagnetics, the term isogon has specific meanings which are described below, an isocline is a line joining points with equal slope. In population dynamics and in geomagnetics, the terms isocline and isoclinic line have specific meanings which are described below, equidistant is a line of equal distance from a given point, line, polyline. In geography, the word isopleth is used for lines that depict a variable which cannot be measured at a point. An example is population density, which can be calculated by dividing the population of a district by the surface area of that district. Each calculated value is presumed to be the value of the variable at the centre of the area, the idea of an isopleth map can be compared with that of a choropleth map
38.
Northern Hemisphere
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The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined as being in the celestial hemisphere relative to the invariable plane of the solar system as Earths North pole. Due to the Earths axial tilt, winter in the Northern Hemisphere lasts from the December solstice to the March Equinox, the dates vary each year due to the difference between the calendar year and the astronomical year. Its surface is 60. 7% water, compared with 80. 9% water in the case of the Southern Hemisphere, the Arctic is the region north of the Arctic Circle. Its climate is characterized by cold winters and cool summers, precipitation mostly comes in the form of snow. The Arctic experiences some days in summer when the Sun never sets, the duration of these phases varies from one day for locations right on the Arctic Circle to several months near the North Pole, which is the middle of the Northern Hemisphere. Between the Arctic Circle and the Tropic of Cancer lies the Northern Temperate Zone, the changes in these regions between summer and winter are generally mild, rather than extreme hot or cold. However, a temperate climate can have very unpredictable weather, tropical regions are generally hot all year round and tend to experience a rainy season during the summer months, and a dry season during the winter months. In the Northern Hemisphere, objects moving across or above the surface of the Earth tend to turn to the right because of the coriolis effect, as a result, large-scale horizontal flows of air or water tend to form clockwise-turning gyres. These are best seen in circulation patterns in the North Atlantic. For the same reason, flows of air down toward the surface of the Earth tend to spread across the surface in a clockwise pattern. Thus, clockwise air circulation is characteristic of high pressure weather cells in the Northern Hemisphere, conversely, air rising from the northern surface of the Earth tends to draw air toward it in a counterclockwise pattern. Hurricanes and tropical storms spin counter-clockwise in the Northern Hemisphere, the shadow of a sundial moves clockwise in the Northern Hemisphere. When viewed from the Northern Hemisphere, the Moon appears inverted compared to a view from the Southern Hemisphere, the North Pole faces away from the galactic center of the Milky Way. The Northern Hemisphere is home to approximately 6.57 billion people which is around 90% of the total human population of 7.3 billion people
39.
Southern Hemisphere
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The Southern Hemisphere is the half sphere of Earth which is south of the equator. It contains all or parts of five continents, four oceans and its surface is 80. 9% water, compared with 60. 7% water in the case of the Northern Hemisphere, and it contains 32. 7% of Earths land. Due to the tilt of Earths rotation relative to the Sun, September 22 or 23 is the vernal equinox and March 20 or 21 is the autumnal equinox. The South Pole is in the middle of the southern hemispherical region, Southern Hemisphere climates tend to be slightly milder than those at similar latitudes in the Northern Hemisphere, except in the Antarctic which is colder than the Arctic. This is because the Southern Hemisphere has significantly more ocean and much land, water heats up. In the Southern Hemisphere the sun passes from east to west through the north, sun-cast shadows turn anticlockwise throughout the day and sundials have the hours increasing in the anticlockwise direction. Cyclones and tropical storms spin clockwise in the Southern Hemisphere due to the Coriolis effect, the southern temperate zone, a subsection of the Southern Hemisphere, is nearly all oceanic. Forests in the Southern Hemisphere have special features which set apart from those in the Northern Hemisphere. Both Chile and Australia share, for example, unique species or Nothofagus. The eucalyptus is native to Australia but is now planted in Southern Africa and Latin America for pulp production and, increasingly. Approximately 800,000,000 humans live in the Southern Hemisphere and this is due to the fact that there is significantly less land in the Southern Hemisphere than in the Northern Hemisphere. Africa Antarctica Asia Australia South America Zealandia Media related to Southern Hemisphere at Wikimedia Commons
40.
Coriolis force
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In physics, the Coriolis force is an inertial force that acts on objects that are in motion relative to a rotating reference frame. In a reference frame with clockwise rotation, the acts to the left of the motion of the object. In one with anticlockwise rotation, the acts to the right. Early in the 20th century, the term Coriolis force began to be used in connection with meteorology, deflection of an object due to the Coriolis force is called the Coriolis effect. Newtons laws of motion describe the motion of an object in a frame of reference. When Newtons laws are transformed to a frame of reference. Both forces are proportional to the mass of the object, the Coriolis force is proportional to the rotation rate and the centrifugal force is proportional to its square. The Coriolis force acts in a perpendicular to the rotation axis. The centrifugal force acts outwards in the direction and is proportional to the distance of the body from the axis of the rotating frame. These additional forces are termed inertial forces, fictitious forces or pseudo forces and they allow the application of Newtons laws to a rotating system. They are correction factors that do not exist in a non-accelerating or inertial reference frame, a commonly encountered rotating reference frame is the Earth. The Coriolis effect is caused by the rotation of the Earth, such motions are constrained by the surface of the Earth, so only the horizontal component of the Coriolis force is generally important. This force causes moving objects on the surface of the Earth to be deflected to the right in the Northern Hemisphere, the horizontal deflection effect is greater near the poles, since the effective rotation rate about a local vertical axis is largest there, and smallest at the equator. This effect is responsible for the rotation of large cyclones, riccioli, Grimaldi, and Dechales all described the effect as part of an argument against the heliocentric system of Copernicus. In other words, they argued that the Earths rotation should create the effect, the effect was described in the tidal equations of Pierre-Simon Laplace in 1778. Gaspard-Gustave Coriolis published a paper in 1835 on the yield of machines with rotating parts. That paper considered the forces that are detected in a rotating frame of reference. Coriolis divided these forces into two categories
41.
Polar low
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A polar low is a small-scale, short-lived atmospheric low pressure system that is found over the ocean areas poleward of the main polar front in both the Northern and Southern Hemispheres. The systems usually have a length scale of less than 1,000 kilometres. They are part of the class of mesoscale weather systems. Polar lows can be difficult to detect using conventional weather reports and are a hazard to high-latitude operations, such as shipping and gas, such winter storms can cause bitter cold and crop freezes. Polar lows have been referred to by other terms, such as polar mesoscale vortex, Arctic hurricane, Arctic low. Today the term is reserved for the more vigorous systems that have near-surface winds of at least 17 m/s. Polar lows were first identified on the satellite imagery that became available in the 1960s. Polar lows dissipate rapidly when they make landfall, Antarctic systems tend to be weaker than their northern counterparts since the air-sea temperature differences around the continent are generally smaller. However, vigorous polar lows can be found over the Southern Ocean, Polar lows can have a wide range of cloud signatures in satellite imagery, but two broad categories of cloud forms have been identified. The first is the spiraliform signature consisting of a number of cloud bands wrapped around the centre of the low and these systems are more common deep within the polar air. The second is a signature that is found more frequently with systems closer to the polar front. Polar lows form for a number of different reasons, and a spectrum of systems is observed on satellite imagery, a number of lows develop on horizontal temperature gradients through baroclinic instability, and these can have the appearance of small frontal depressions. At the other extreme are the polar lows with extensive cumulonimbus clouds, Polar lows can occur at any time during the year, but cyclogenesis takes on different characteristics depending on season. Although cyclonic activity is most prevalent in the Eurasian Arctic with approximately 15 cyclones per winter, polar lows also occur in Greenland, if you get the right atmospheric conditions during those two months, they can really accelerate the ice loss. If you don’t, they can slow down any melting momentum you had, in stark contrast, summer polar cyclones may not form for several years, and tend to be weaker than winter cyclones. The only infrastructure damage that occurs as a result of a polar cyclone is to oil. Some cargo and shipping vessels are also affected, although there are minimal or no reports of losses in recent years as the result of a polar low. Polar lows are very difficult to forecast and an approach is often used
42.
Thermal low
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Over land, intense, rapid solar heating of the land surface results in heating of the lowest layers of the atmosphere via reradiated energy in the infrared spectrum. The resulting hotter air is less dense than surrounding cooler air and this, combined with the rising of the hot air, results in the formation of a low pressure area. Elevated areas can enhance the strength of the low as they warm more quickly than the atmosphere which surrounds them at the same altitude. Over the water, instability lows form during the winter when the air overlying the land is colder than the water body. Thermal lows tend to have weak circulations, and can extend to 3,100 metres in height, thermal lows over the western and southern portions of North America, northern Africa, and southeast Asia are strong enough to lead to summer monsoon conditions. Development of thermal lows inland of the lead to the development of sea breezes. Sea breezes combined with rugged topography near the coast can encourage poor air quality, in deserts, lack of ground and plant moisture that would normally provide evaporative cooling can lead to intense, rapid solar heating of the lower layers of air. The hot air is less dense than surrounding cooler air and this, combined with the rising of the hot air, results in a low pressure area called a thermal low. During the cold season, warm water bodies such as the Great Lakes can induce an instability low. Thermal lows which develop near sea level can build in height during the season, or summer, to the elevation of the 700 hPa pressure surface. Heat lows normally are stationary and have a weak cyclonic circulation, as they are strongest at the surface and warm near their center, and weaker aloft where the air is more stable, the thermal low is considered warm core. The formation of the heat low over northern Africa leads to a westerly jet stream from June into October. Monsoons are caused by the amplitude of the seasonal cycle of land temperature compared to that of nearby oceans. Additionally, the heat capacity of liquid water is significantly higher than that of most materials that make up land. The hot air over the land tends to rise, creating an area of low pressure and this creates a steady wind blowing toward the land, bringing the moist near-surface air over the oceans with it. Similar rainfall is caused by the moist ocean air being lifted upwards by mountains, surface heating, convergence at the surface, divergence aloft, however the lifting occurs, the air cools due expansion in lower pressure, which in turn produces condensation. In winter, the land cools off quickly, but the keeps the heat longer due to its higher specific heat. The hot air over the ocean rises, creating a low pressure area, the sea is warmed by the sun to a greater depth than the land due to its greater specific heat
43.
Anticyclone
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Effects of surface-based anticyclones include clearing skies as well as cooler, drier air. Fog can also form overnight within a region of higher pressure, sir Francis Galton first discovered anticyclones in the 1860s. Preferred areas within a flow pattern in higher levels of the hydrosphere are beneath the western side of troughs. High-pressure systems are referred to as anticyclones. Their circulation is sometimes referred to as cum sole, subtropical high pressure zones form along the descending portion of the Hadley cell circulation. Upper-level high-pressure areas lie over tropical cyclones due to their warm core nature, surface anticyclones form due to downward motion through the troposphere, the atmospheric layer where weather occurs. Preferred areas within a flow pattern in higher levels of the troposphere are beneath the western side of troughs. Because they weaken with height, these systems are cold. Heating of the earth near the equator forces upward motion and convection along the trough or intertropical convergence zone. The divergence over the near-equatorial trough leads to air rising and moving away from the equator aloft, as air moves towards the mid-latitudes, it cools and sinks leading to subsidence near the 30° parallel of both hemispheres. This circulation known as the Hadley cell forms the subtropical ridge, many of the worlds deserts are caused by these climatological high-pressure areas. Because these anticyclones strengthen with height, they are known as warm core ridges, in the absence of rotation, the wind tends to blow from areas of high pressure to areas of low pressure. The stronger the pressure difference between a system and a low-pressure system, the stronger the wind. The coriolis force caused by Earths rotation gives winds within high-pressure systems their clockwise circulation in the northern hemisphere, friction with land slows down the wind flowing out of high-pressure systems and causes wind to flow more outward from the center. High-pressure systems are associated with light winds at the surface and subsidence of air from higher portions of the troposphere. Subsidence will generally warm an air mass by adiabatic heating, thus, high pressure typically brings clear skies. Because no clouds are present to reflect sunlight during the day, there is more incoming solar radiation, at night, the absence of clouds means that outgoing longwave radiation is not blocked, giving cooler diurnal low temperatures in all seasons. If the surface level relative humidity rises towards 100 percent overnight, the movement of continental arctic air masses to lower latitudes produces strong but vertically shallow high-pressure systems
44.
Air mass
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In meteorology, an air mass is a volume of air defined by its temperature and water vapor content. Air masses cover many hundreds or thousands of miles. They are classified according to latitude and their continental or maritime source regions, colder air masses are termed polar or arctic, while warmer air masses are deemed tropical. Continental and superior air masses are dry while maritime and monsoon air masses are moist, weather fronts separate air masses with different density characteristics. Once an air mass moves away from its region, underlying vegetation. Classification schemes tackle an air mass characteristics, as well as modification, the Bergeron classification is the most widely accepted form of air mass classification, though others have produced more refined versions of this scheme over different regions of the globe. Air mass classification involves three letters, the first letter describes its moisture properties, with c used for [[continental air masses and m for maritime air masses. The second letter describes the characteristic of its source region, T for Tropical, P for Polar, A for arctic or Antarctic, M for monsoon, E for Equatorial. For instance, an air mass originating over the desert southwest of the United States in summer may be designated cT, an air mass originating over northern Siberia in winter may be indicated as cA. The stability of an air mass may be using a third letter, either k or w. An example of this might be an air mass blowing over the Gulf Stream. For example, a series of fronts over the Pacific might show an air mass denoted mPk followed by another denoted mPk, another convention utilizing these symbols is the indication of modification or transformation of one type to another. For instance, an Arctic air mass blowing out over the Gulf of Alaska may be shown as cA-mPk, yet another convention indicates the layering of air masses in certain situations. For instance, the overrunning of an air mass by an air mass from the Gulf of Mexico over the Central United States might be shown with the notation mT/cP. Arctic, Antarctic, and polar air masses are cold, the qualities of arctic air are developed over ice and snow-covered ground. Arctic air is cold, colder than polar air masses. Arctic air can be shallow in the summer, and rapidly modify as it moves equatorward, Polar air masses develop over higher latitudes over the land or ocean, are very stable, and generally shallower than arctic air. Polar air over the ocean loses its stability as it gains moisture over warmer ocean waters, Tropical and equatorial air masses are hot as they develop over lower latitudes
45.
Humidity
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Humidity is the amount of water vapor present in the air. Water vapor is the state of water and is invisible. Humidity indicates the likelihood of precipitation, dew, or fog, higher humidity reduces the effectiveness of sweating in cooling the body by reducing the rate of evaporation of moisture from the skin. This effect is calculated in an index table or humidex. The amount of vapor that is needed to achieve saturation increases as the temperature increases. As the temperature of a parcel of water becomes lower it will not reach the point of saturation without adding or losing water mass. The differences in the amount of vapor in a parcel of air can be quite large. For example, a parcel of air that is near saturation may contain 28 grams of water per cubic meter of air at 30 °C, there are three main measurements of humidity, absolute, relative and specific. Absolute humidity is the content of air expressed in gram per cubic meter. Relative humidity, expressed as a percent, measures the current absolute humidity relative to the maximum for that temperature, specific humidity is the ratio of the mass of water vapor to the total mass of the moist air parcel. Absolute humidity is the mass of water vapor present in a given volume of air. It does not take temperature into consideration, absolute humidity in the atmosphere ranges from near zero to roughly 30 grams per cubic meter when the air is saturated at 30 °C. Absolute humidity is the mass of the vapor, divided by the volume of the air and water vapor mixture. The absolute humidity changes as air temperature or pressure changes and this makes it unsuitable for chemical engineering calculations, e. g. for clothes dryers, where temperature can vary considerably. Mass of water per unit volume as in the equation above is defined as volumetric humidity. Because of the confusion, British Standard BS1339 suggests avoiding the term absolute humidity. Units should always be carefully checked, many humidity charts are given in g/kg or kg/kg, but any mass units may be used. The field concerned with the study of physical and thermodynamic properties of mixtures is named psychrometrics
46.
Cold front
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A cold front is defined as the leading edge of a cooler mass of air, replacing at ground level a warmer mass of air, which lies within a fairly sharp surface trough of low pressure. It forms in the wake of a cyclone, at the leading edge of its cold air advection pattern. Temperature changes across the boundary can exceed 30 °C, when enough moisture is present, rain can occur along the boundary. If there is significant instability along the boundary, a line of thunderstorms can form along the frontal zone. If instability is less, a shield of rain can move in behind the front. Cold fronts are stronger in the fall and spring transition seasons, when a cold front catches up with the preceding warm front, the portion of the boundary that does so is then known as an occluded front. The cooler and denser air wedges under the less-dense warmer air and this upward motion causes lowered pressure along the cold front and can cause the formation of a narrow line of showers and thunderstorms when enough moisture is present. On weather maps, the position of the cold front is marked with the symbol of a blue line of triangles/spikes pointing in the direction of travel. Cold fronts move faster than warm fronts and can produce changes in weather. Since cold air is denser than air, it rapidly replaces the warm air preceding the boundary. Normally, cold fronts can be marked by these characteristics, *provided there is sufficient moisture, if the cold front is highly unstable, cumulonimbus clouds producing thunderstorms commonly form along the front. Anvil cirrus clouds may spread a considerable distance downwind from the thunderstorms, the other cloud types associated with a cold front depend on atmospheric conditions such as air mass stability and wind shear. With significant airmass instability, vertically developed cumulus or cumulonimbus with showers, small and unchanging amounts of cumulus or cirrus clouds in an otherwise clear sky are usually indications of continuing fair weather as long as the barometric pressure remains comparatively high. A cold front commonly brings a band of precipitation that follows along the leading edge of the cold front. These bands of precipitation are very strong in nature. In the spring, these fronts can be very strong. During the winter months, cold fronts come through an area with little or no precipitation. Wider rain bands can occur behind cold fronts tend to have more stratiform
