Radio is the technology of signalling or communicating using radio waves. Radio waves are electromagnetic waves of frequency between 300 gigahertz, they are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, received by a radio receiver connected to another antenna. Radio is widely used in modern technology, in radio communication, radio navigation, remote control, remote sensing and other applications. In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking and satellite communication among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal in the transmitter. In radar, used to locate and track objects like aircraft, ships and missiles, a beam of radio waves emitted by a radar transmitter reflects off the target object, the reflected waves reveal the object's location. In radio navigation systems such as GPS and VOR, a mobile receiver receives radio signals from navigational radio beacons whose position is known, by measuring the arrival time of the radio waves the receiver can calculate its position on Earth.
In wireless remote control devices like drones, garage door openers, keyless entry systems, radio signals transmitted from a controller device control the actions of a remote device. Applications of radio waves which do not involve transmitting the waves significant distances, such as RF heating used in industrial processes and microwave ovens, medical uses such as diathermy and MRI machines, are not called radio; the noun radio is used to mean a broadcast radio receiver. Radio waves were first identified and studied by German physicist Heinrich Hertz in 1886; the first practical radio transmitters and receivers were developed around 1895-6 by Italian Guglielmo Marconi, radio began to be used commercially around 1900. To prevent interference between users, the emission of radio waves is regulated by law, coordinated by an international body called the International Telecommunications Union, which allocates frequency bands in the radio spectrum for different uses. Radio waves are radiated by electric charges undergoing acceleration.
They are generated artificially by time varying electric currents, consisting of electrons flowing back and forth in a metal conductor called an antenna. In transmission, a transmitter generates an alternating current of radio frequency, applied to an antenna; the antenna radiates the power in the current as radio waves. When the waves strike the antenna of a radio receiver, they push the electrons in the metal back and forth, inducing a tiny alternating current; the radio receiver connected to the receiving antenna detects this oscillating current and amplifies it. As they travel further from the transmitting antenna, radio waves spread out so their signal strength decreases, so radio transmissions can only be received within a limited range of the transmitter, the distance depending on the transmitter power, antenna radiation pattern, receiver sensitivity, noise level, presence of obstructions between transmitter and receiver. An omnidirectional antenna transmits or receives radio waves in all directions, while a directional antenna or high gain antenna transmits radio waves in a beam in a particular direction, or receives waves from only one direction.
Radio waves travel through a vacuum at the speed of light, in air at close to the speed of light, so the wavelength of a radio wave, the distance in meters between adjacent crests of the wave, is inversely proportional to its frequency. In radio communication systems, information is carried across space using radio waves. At the sending end, the information to be sent is converted by some type of transducer to a time-varying electrical signal called the modulation signal; the modulation signal may be an audio signal representing sound from a microphone, a video signal representing moving images from a video camera, or a digital signal consisting of a sequence of bits representing binary data from a computer. The modulation signal is applied to a radio transmitter. In the transmitter, an electronic oscillator generates an alternating current oscillating at a radio frequency, called the carrier wave because it serves to "carry" the information through the air; the information signal is used to modulate the carrier, varying some aspect of the carrier wave, impressing the information on the carrier.
Different radio systems use different modulation methods: AM - in an AM transmitter, the amplitude of the radio carrier wave is varied by the modulation signal. FM - in an FM transmitter, the frequency of the radio carrier wave is varied by the modulation signal. FSK - used in wireless digital devices to transmit digital signals, the frequency of the carrier wave is shifted periodically between two frequencies that represent the two binary digits, 0 and 1, to transmit a sequence of bits. OFDM - a family of complicated digital modulation methods widely used in high bandwidth systems such as WiFi networks, digital television broadcasting, digital audio broadcasting to transmit digital data using a minimum of radio spectrum bandwidth. OFDM has higher spectral efficiency and more resistance to fading than AM or FM. Multiple radio carrier waves spaced in frequency are transmitted within the radio channel, with each carrier modulated with bits from the incoming bitstream
The United States of America known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U. S. is the third most populous country. The capital is Washington, D. C. and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico; the State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean; the U. S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The diverse geography and wildlife of the United States make it one of the world's 17 megadiverse countries.
Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago. European colonization began in the 16th century; the United States emerged from the thirteen British colonies established along the East Coast. Numerous disputes between Great Britain and the colonies following the French and Indian War led to the American Revolution, which began in 1775, the subsequent Declaration of Independence in 1776; the war ended in 1783 with the United States becoming the first country to gain independence from a European power. The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties; the United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories, displacing Native American tribes, admitting new states until it spanned the continent by 1848. During the second half of the 19th century, the Civil War led to the abolition of slavery.
By the end of the century, the United States had extended into the Pacific Ocean, its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power; the United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, a permanent member of the United Nations Security Council. Sweeping civil rights legislation, notably the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968, outlawed discrimination based on race or color. During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 U. S. Moon landing; the end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower. The United States is the world's oldest surviving federation, it is a representative democracy.
The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States, other international organizations. The United States is a developed country, with the world's largest economy by nominal GDP and second-largest economy by PPP, accounting for a quarter of global GDP; the U. S. economy is post-industrial, characterized by the dominance of services and knowledge-based activities, although the manufacturing sector remains the second-largest in the world. The United States is the world's largest importer and the second largest exporter of goods, by value. Although its population is only 4.3% of the world total, the U. S. holds 31% of the total wealth in the world, the largest share of global wealth concentrated in a single country. Despite wide income and wealth disparities, the United States continues to rank high in measures of socioeconomic performance, including average wage, human development, per capita GDP, worker productivity.
The United States is the foremost military power in the world, making up a third of global military spending, is a leading political and scientific force internationally. In 1507, the German cartographer Martin Waldseemüller produced a world map on which he named the lands of the Western Hemisphere America in honor of the Italian explorer and cartographer Amerigo Vespucci; the first documentary evidence of the phrase "United States of America" is from a letter dated January 2, 1776, written by Stephen Moylan, Esq. to George Washington's aide-de-camp and Muster-Master General of the Continental Army, Lt. Col. Joseph Reed. Moylan expressed his wish to go "with full and ample powers from the United States of America to Spain" to seek assistance in the revolutionary war effort; the first known publication of the phrase "United States of America" was in an anonymous essay in The Virginia Gazette newspaper in Williamsburg, Virginia, on April 6, 1776. The second draft of the Articles of Confederation, prepared by John Dickinson and completed by June 17, 1776, at the latest, declared "The name of this Confederation shall be the'United States of America'".
The final version of the Articles sent to the states for ratification in late 1777 contains the sentence "The Stile of this Confederacy shall be'The United States of America'". In June 1776, Thomas Jefferson wrote the phrase "UNITED STATES OF AMERICA" in all capitalized letters in the headline of his "original Rough draught" of the Declaration of Independence; this draft of the document did not surface unti
WROC-TV, virtual channel 8, is a CBS-affiliated television station licensed to Rochester, New York, United States. Owned by the Nexstar Media Group, WROC-TV has studios on Humboldt Street in downtown Rochester, its transmitter is located on Pinnacle Hill in Brighton, New York. WROC-TV is Rochester's oldest television station, signing on June 11, 1949, as WHAM-TV, an NBC affiliate on channel 6, it was owned by Stromberg-Carlson, a telephone equipment manufacturer, along with WHAM radio. The station was affiliated with the now-defunct DuMont Television Network. WHAM-TV moved to channel 5 on July 24, 1954, as part of a revision of upstate New York's VHF allotments resulting from the Federal Communications Commission's Sixth Report and Order of 1952. However, WHAM-TV on channel 5 dealt with interference issues from CBLT, a CBC Television station from Toronto, after that station moved from its original channel 9 allocation to channel 6 in 1956. CBLT was replaced on channel 9 by CFTO-TV in 1960, that channel relocation would play an indirect role in the station's second frequency shift, eight years later.
Stromberg-Carlson merged with General Dynamics in 1955. General Dynamics was not interested in owning broadcast outlets, put the WHAM-TV outlets on the market. In 1956, WHAM-TV was sold to Transcontinent Broadcasting, which owned WGR radio and WGR-TV in Buffalo; the new owners changed the call letters to the current WROC-TV. In 1961, Transcontinent sold the station to Veterans Broadcasting Company, which subsequently sold its half of what is today WHEC-TV to the Gannett Company based in Rochester. Under Veterans' ownership, WROC-TV moved to channel 8 on September 8, 1962, as part of another channel allocation change, this one being a switch involving Rochester and Syracuse; the FCC moved WROC-TV's former channel 5 east to Syracuse, it was taken by Meredith Corporation-owned WHEN-TV, on channel 8. The move allowed a new station on channel 9 to enter the Syracuse market. Veterans Broadcasting merged with Rust Craft Broadcasting in 1964. Rust Craft was sold to Ziff Davis in 1979. Ziff Davis sold WROC-TV and sister stations in Saginaw, Augusta and Steubenville, Ohio to Television Station Partners LP in 1983.
Television Station Partners sold WROC-TV, along with the WEYI-TV and WTOV-TV, to Smith Broadcasting in 1996. Nexstar purchased WROC-TV in 1999. Under the stewardship of Television Station Partners, WROC-TV made another switch: On July 1, 1989, after 40 years with NBC, channel 8 swapped network affiliations with WHEC-TV and became a CBS station; this move was the result of the station's poor performance and constant preemptions of NBC network programming. For many years, WROC-TV was one of three Rochester area stations offered on cable in the Ottawa–Gatineau and Eastern Ontario regions; the Rochester area stations were replaced with Detroit stations when the microwave relay system that provided these signals was discontinued. Until January 2009, WROC-TV was available in many Central Ontario communities such as Belleville and Lindsay. On July 9, 2012, WROC-TV replaced Louisville's WLKY on Time Warner Cable systems in that station's region, when WLKY's owners, Hearst Television, pulled its stations off Time Warner Cable's systems in a retransmission dispute.
However, Nexstar complained that Time Warner Cable has used their signals outside their markets without permission, while Time Warner Cable was within its rights to use their signals as replacements until a deal with Hearst is reached. WROC-TV, for its part, made the best of its predicament, naming the administrator of a Facebook group of tongue-in-cheek Louisvillean WROC-TV fans its fan of the week and making a handful of other shout-outs to its emerging Louisville fanbase; the substitution of WROC-TV in place of WLKY lasted until July 19, 2012, when a deal was reached between Hearst and Time Warner. The station's digital signal is multiplexed: On June 15, 2016, Nexstar announced that it has entered into an affiliation agreement with Katz Broadcasting for the Escape, Laff and Bounce TV networks, bringing one or more of the four networks to 81 stations owned and/or operated by Nexstar, including WROC-TV; as a result, WROC-TV added two additional subchannels carrying Escape and Laff on August 20, 2016.
WROC-TV discontinued regular programming on its analog signal, over VHF channel 8, at 11:35 p.m. on June 12, 2009, the official date in which full-power television stations in the United States transitioned from analog to digital broadcasts under federal mandate. The station's digital signal remained on its pre-transition UHF channel 45. Through the use of PSIP, digital television receivers display the station's virtual channel as its former VHF analog channel 8. Syndicated programming on WROC-TV includes: Wheel of Fortune, Jeopardy!, Inside Edition, The Dr. Oz Show. All are distributed by CBS Television Distribution. In August 1957, WROC-TV began airing the area's first 11 o'clock broadcast called Eleventh Hour News. Regular sports segments were added to the show on April 7, 1958. WROC-TV enjoyed ratings dominance with popular anchorman Tom weatherman Bob Mills. Anne Keefe, another well-known talent who split time between WROC radio and TV, contributed to the station's s
Television, sometimes shortened to tele or telly, is a telecommunication medium used for transmitting moving images in monochrome, or in color, in two or three dimensions and sound. The term can refer to a television set, a television program, or the medium of television transmission. Television is a mass medium for advertising and news. Television became available in crude experimental forms in the late 1920s, but it would still be several years before the new technology would be marketed to consumers. After World War II, an improved form of black-and-white TV broadcasting became popular in the United States and Britain, television sets became commonplace in homes and institutions. During the 1950s, television was the primary medium for influencing public opinion. In the mid-1960s, color broadcasting was introduced in most other developed countries; the availability of multiple types of archival storage media such as Betamax, VHS tape, local disks, DVDs, flash drives, high-definition Blu-ray Discs, cloud digital video recorders has enabled viewers to watch pre-recorded material—such as movies—at home on their own time schedule.
For many reasons the convenience of remote retrieval, the storage of television and video programming now occurs on the cloud. At the end of the first decade of the 2000s, digital television transmissions increased in popularity. Another development was the move from standard-definition television to high-definition television, which provides a resolution, higher. HDTV may be transmitted in various formats: 1080p, 720p. Since 2010, with the invention of smart television, Internet television has increased the availability of television programs and movies via the Internet through streaming video services such as Netflix, Amazon Video, iPlayer and Hulu. In 2013, 79 % of the world's households owned; the replacement of early bulky, high-voltage cathode ray tube screen displays with compact, energy-efficient, flat-panel alternative technologies such as LCDs, OLED displays, plasma displays was a hardware revolution that began with computer monitors in the late 1990s. Most TV sets sold in the 2000s were flat-panel LEDs.
Major manufacturers announced the discontinuation of CRT, DLP, fluorescent-backlit LCDs by the mid-2010s. In the near future, LEDs are expected to be replaced by OLEDs. Major manufacturers have announced that they will produce smart TVs in the mid-2010s. Smart TVs with integrated Internet and Web 2.0 functions became the dominant form of television by the late 2010s. Television signals were distributed only as terrestrial television using high-powered radio-frequency transmitters to broadcast the signal to individual television receivers. Alternatively television signals are distributed by coaxial cable or optical fiber, satellite systems and, since the 2000s via the Internet; until the early 2000s, these were transmitted as analog signals, but a transition to digital television is expected to be completed worldwide by the late 2010s. A standard television set is composed of multiple internal electronic circuits, including a tuner for receiving and decoding broadcast signals. A visual display device which lacks a tuner is called a video monitor rather than a television.
The word television comes from Ancient Greek τῆλε, meaning'far', Latin visio, meaning'sight'. The first documented usage of the term dates back to 1900, when the Russian scientist Constantin Perskyi used it in a paper that he presented in French at the 1st International Congress of Electricity, which ran from 18 to 25 August 1900 during the International World Fair in Paris; the Anglicised version of the term is first attested in 1907, when it was still "...a theoretical system to transmit moving images over telegraph or telephone wires". It was "...formed in English or borrowed from French télévision." In the 19th century and early 20th century, other "...proposals for the name of a then-hypothetical technology for sending pictures over distance were telephote and televista." The abbreviation "TV" is from 1948. The use of the term to mean "a television set" dates from 1941; the use of the term to mean "television as a medium" dates from 1927. The slang term "telly" is more common in the UK; the slang term "the tube" or the "boob tube" derives from the bulky cathode ray tube used on most TVs until the advent of flat-screen TVs.
Another slang term for the TV is "idiot box". In the 1940s and throughout the 1950s, during the early rapid growth of television programming and television-set ownership in the United States, another slang term became used in that period and continues to be used today to distinguish productions created for broadcast on television from films developed for presentation in movie theaters; the "small screen", as both a compound adjective and noun, became specific references to television, while the "big screen" was used to identify productions made for theatrical release. Facsimile transmission systems for still photographs pioneered methods of mechanical scanning of images in the early 19th century. Alexander Bain introduced the facsimile machine between 1843 and 1846. Frederick Bakewell demonstrated a working laboratory version in 1851. Willoughby Smith discovered the photoconductivity of the element selenium in 1873; as a 23-year-old German university student, Paul Julius Gottlieb Nipkow proposed and patented the Nipkow disk in 1884.
This was a spinning disk with a spiral pattern of holes in it, so each hole scanned a line of the image. Although he never built a working model
Mississippi State University
The Mississippi State University for Agriculture and Applied Science known as Mississippi State University, is a public land-grant research university adjacent to Starkville, Mississippi. With 21,353 students at its main campus, it is the largest campus by enrollment in the state, it is classified in the category of "R1: Doctoral Universities – Very High Research Activity" by the Carnegie Foundation and has a total research and development budget of $239.4 million, the largest in Mississippi. It is listed as one of the state's flagship universities; the university was chartered as Mississippi Agricultural & Mechanical College on February 28, 1878 and admitted its first students in 1880. Organized into 12 colleges and schools, the university offers over 180 baccalaureate and professional degree programs, is home to Mississippi's only accredited programs in architecture and veterinary medicine. Mississippi State participates in the National Sea Grant College Program and National Space Grant College and Fellowship Program.
The university's main campus in Starkville is supplemented by auxiliary campuses in Meridian and Vicksburg, Mississippi. The 19th and current president of Mississippi State is Mark E. Keenum, a former United States Under Secretary of Agriculture. Mississippi State's intercollegiate sports teams, known as the Mississippi State Bulldogs, compete in NCAA Division I athletics as members of the Southeastern Conference's western division. Mississippi State was a founding member of the SEC in 1932. In their more-than 120-year history, the Bulldogs have won 21 individual national championships and 30 regular season conference championships; the school is noted for a pervasive baseball fan culture, with Dudy Noble Field holding 17 of the top 25 all-time NCAA attendance records and the school's Left Field Lounge being described as an epicenter of college baseball. The university began as The Agricultural and Mechanical College of the State of Mississippi, one of the national land-grant colleges established after Congress passed the Morrill Act in 1862.
It was created by the Mississippi Legislature on February 28, 1878, to fulfill the mission of offering training in "agriculture and the mechanical arts... without excluding other scientific and classical studies, including military tactics." The university received its first students in the fall of 1880 in the presidency of General Stephen D. Lee. In 1887 Congress passed the Hatch Act, which provided for the establishment of the Agricultural Experiment Station in 1888; the Cooperative Extension Service was established in 1914 by the Smith-Lever Act. The university redefined by the Legislature. In 1932, the Legislature renamed the university as Mississippi State College. In 1958 the Legislature renamed the university Mississippi State University in recognition of its academic development and addition of graduate programs; the Graduate School had been organized, doctoral degree programs had begun, the School of Forest Resources had been established, the College of Arts and Sciences had replaced the General Science School.
The university was uneventfully desegregated in July 1965, when Richard E. Holmes, a graduate of Henderson High School in Starkville, became the first African-American student to enroll; the Civil Rights Act of 1964 was passed by Congress the year before, the Voting Rights Act of 1965 was being debated, the United States Supreme Court had ruled in Brown v. Board of Education that segregation of public schools was unconstitutional; the School of Architecture admitted its first students in 1973, the College of Veterinary Medicine admitted its first class in 1977. The MSU Vet school is the largest veterinary school under one roof in the nation; the School of Accountancy was established in 1979. The University Honors Program was founded in 1968 to provide more rigorous course curricula for academically talented students and support guest lecture series and distinguished external scholarships; the program has a separate college. This was made possible by funding by Bobby Shackouls, an MSU alumnus and retired CEO, who donated US$10 million to found the Judy and Bobby Shackouls Honors College in April 2006.
MSU started a joint Ph. D. program in engineering with San Jose State University in California, allowing an increase in research for both universities, as well as enhancing the stature of both engineering colleges. In March 2009, Mississippi State announced the conclusion of the university's seven-year capital campaign, with more than $462 million received in private gifts and pledges. Mississippi State University is accredited by the Commission on Colleges of the Southern Association of Colleges and Schools to award baccalaureate, master's, doctoral degrees. Today, the university has the following colleges and schools: As of Fall 2011, Mississippi State's enrollment was 20,424; the university has 160 buildings, the grounds comprise about 4,200 acres, including farms and woodlands of the Experiment Station. The university owns an additional 80,000 acres across the state. Mississippi State University operates an off-campus, degree-granting center in Meridian that offers undergraduate and graduate programs.
In cooperation with the U. S. Army Engineer Waterways Experiment Station, the College of Engineering offers the Master of Science degree to students in Vicksburg. Mississippi State's campus is centered on the main quadrangle, called the Drill Field due to its heavy use by the Corps of Cadets prior to the end of World War II; the Drill Field is defined at its north and south ends by the mirror-image buildings, Lee Hall (th
American Meteorological Society
The American Meteorological Society is the premier scientific and professional organization in the United States promoting and disseminating information about the atmospheric and hydrologic sciences. Its mission is to advance the atmospheric and related sciences, technologies and services for the benefit of society. Founded in 1919 by Charles Franklin Brooks, the American Meteorological Society has a membership of more than 13,000 weather and climate scientists, researchers, educators and enthusiasts. AMS offers numerous programs and services in the sphere of water and climate sciences, it publishes eleven atmospheric and related oceanic and hydrologic journals, sponsors as many as twelve conferences annually, administers professional certification programs and awards. The AMS Policy and Education programs promote scientific knowledge and work to increase public understanding of science. There is an extensive network of local and student AMS chapters. AMS headquarters is located at 45 Beacon Street adjacent to the Boston Common in Boston, Massachusetts.
The headquarters building was designed by Charles Bulfinch as the third Harrison Gray Otis House in 1806 and was purchased and renovated by AMS in 1958, with staff moving into the building in 1960. In 2012, AMS purchased the building next door at 44 Beacon Street designed by Bulfinch. AMS maintains an office in Washington, D. C. at 1200 New York Avenue NW inside the AAAS headquarters. AMS maintains professional certification programs: the Certified Broadcast Meteorologist sets a professional standard in broadcast meteorology and the Certified Consulting Meteorologist establishes high standards of technical competence and experience for consultants who provide advice in meteorology to the public; the AMS Seal of Approval was launched in 1957 to recognize on-air meteorologists for their sound delivery of weather information to the general public. Many seal holders are still active, though the original Seal was succeeded by the CBM; those looking for an expert can consult the listings of all AMS Certified individuals.
AMS recognizes excellent work with over 30 different awards ranging from outstanding research contributions in specific fields to awards for excellence in teaching or broadcasting, outstanding books, exceptional service in forecasting, more including its highest honor: the Carl-Gustaf Rossby Medal. AMS awards more than $100,000 annually in undergraduate and graduate level scholarships and fellowships. AMS publishes eleven peer reviewed scientific journals, as well as books, monographs, accounting for more than 34,000 pages each year. AMS journals are ranked at or near the top of their fields for impact factor. In addition, AMS publishes the Glossary of Meteorology, a blog and the scientific database Meteorological and Geoastrophysical Abstracts. AMS is a member of Crossref, Portico, CHORUS, CLOCKSS; the AMS Policy Program works to increase public understanding of the role of scientific information in societal advancement and helps policy-makers ground their decisions in the best available scientific knowledge.
It carries out research, holds periodic briefings that allow experts to inform policy makers directly on established scientific understanding and the latest policy-relevant research, hosts an annual Summer Policy Colloquium to introduce Earth scientists to the federal policy process. The Congressional Science Fellowship places an AMS scientist on the staff of a member of Congress for one full year. AMS issues and periodically updates four different types of statements on topics that fall within the scope of AMS expertise: Information statements aim to provide a trustworthy and scientifically up-to-date explanation of scientific issues of concern to the public at large, they deal with subjects such as climate drought. Policy statements are aimed at officials of government or international bodies and may articulate the state of scientific understanding, raise awareness of a scientific issue, or make policy recommendations based on the professional and scientific expertise and perspectives of the AMS Professional guidance statements alert AMS members to urgent or important AMS, professional or scientific matters.
Best Practice statements inform AMS members and the public about AMS endorsed best practices across the weather and climate enterprise and promote scientifically-based standards and practices. AMS organizes a large number national and international meetings, specialized conferences and workshops. Annually, more than 6,000 people attend AMS meetings covering science and applications in the atmospheric and related oceanographic and hydrologic sciences. In addition to the AMS Annual Meeting, the 98th of, held in Austin, Texas in 2018, a number of specialty meetings are held each year. AMS records oral presentations given at its meetings and posts them online for anyone to view free of charge. Over thirty conferences and symposia are held concurrently during the AMS Annual Meeting, during which more than 2000 Oral Presentations are given, more than 1000 Posters are presented; the AMS Annual Meeting features an exhibits program, where companies and organizations participate. The AMS Education Program offers training and undergraduate course curriculum to educate the next generation and increase scientific literacy.
It claims to have trained over 100,000 teachers. AMS partners with NOAA, NASA the NSF and the U
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, it was not until after the elucidation of the laws of physics and more the development of the computer, allowing for the automated solution of a great many equations that model the weather, in the latter half of the 20th century that significant breakthroughs in weather forecasting were achieved. An important domain of weather forecasting is marine weather forecasting as it relates to maritime and coastal safety, in which weather effects include atmospheric interactions with large bodies of water. Meteorological phenomena are observable weather events that are explained by the science of meteorology.
Meteorological phenomena are described and quantified by the variables of Earth's atmosphere: temperature, air pressure, water vapour, mass flow, the variations and interactions of those variables, how they change over time. Different spatial scales are used to describe and predict weather on local and global levels. Meteorology, atmospheric physics, atmospheric chemistry are sub-disciplines of the atmospheric sciences. Meteorology and hydrology compose the interdisciplinary field of hydrometeorology; the interactions between Earth's atmosphere and its oceans are part of a coupled ocean-atmosphere system. Meteorology has application in many diverse fields such as the military, energy production, transport and construction; the word meteorology is from the Ancient Greek μετέωρος metéōros and -λογία -logia, meaning "the study of things high in the air". The ability to predict rains and floods based on annual cycles was evidently used by humans at least from the time of agricultural settlement if not earlier.
Early approaches to predicting weather were practiced by priests. Cuneiform inscriptions on Babylonian tablets included associations between rain; the Chaldeans differentiated 46 ° halos. Ancient Indian Upanishads contain mentions of seasons; the Samaveda mentions sacrifices to be performed. Varāhamihira's classical work Brihatsamhita, written about 500 AD, provides evidence of weather observation. 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; the book De Mundo noted If the flashing body is set on fire and rushes violently to the Earth it is called a thunderbolt. They are all called ` swooping bolts'. Lightning is sometimes smoky, is called'smoldering lightning". At other times, it travels in crooked lines, 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 and in weather forecasting for nearly 2,000 years. 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, in which he deals with the application of meteorology to agriculture during the Muslim Agricultural Revolution, he describes the meteorological character of the sky, the planets and constellations, the sun and moon, the lunar phases indicating seasons and rain, the anwa, atmospheric phenomena such as winds, lightning, floods, rivers, lakes. Early attempts at predicting weather were related to prophecy and divining, were sometimes based on astrological ideas. Admiral FitzRoy tried to separate scientific approaches from prophetic ones. Ptolemy wrote on the atmospheric refraction of light in the context of astronomical observations. In 1021, Alhazen showed that atmospheric refraction is responsible for twilight.
St. Albert the Great was the first to propose that each drop of falling rain had the form of a small sphere, that this form meant that the rainbow was produced by light interacting with each raindrop. Roger Bacon was the first to calculate the angular size of the rainbow, he stated. 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 explained the secondary rainbow. In 1716, Edmund Halley suggested that aurorae are caused by "magnetic effluvia" moving along the Earth's magnetic field lines. In 1441, King Sejong's son, Prince Munjong of Korea, invented the first standardized rain gauge; these were sent throughout the Joseon dynasty of Korea as an official tool to assess land taxes based