United States Department of Commerce
The United States Department of Commerce is the Cabinet department of the United States government concerned with promoting economic growth. Among its tasks are gathering economic and demographic data for business and government decision-making and this organizations main purpose is to create jobs, promote economic growth, encourage sustainable development and improve standards of living for all Americans. The Department of Commerce headquarters is the Herbert C. Hoover Building in Washington, the department was originally created as the United States Department of Commerce and Labor on February 14,1903. It was subsequently renamed the Department of Commerce on March 4,1913, as the bureaus, in 1940, the Weather Bureau was transferred from the Agriculture Department, and the Civil Aeronautics Authority was merged into the department. In 1949, the Public Roads Administration was added to the department due to the dissolution of the Federal Works Agency, in 1958, the independent Federal Aviation Agency was created and the Civil Aeronautics Authority was abolished.
In 1966, the Bureau of Public Roads was transferred to the newly created Department of Transportation, the National Oceanic and Atmospheric Administration was created on October 3,1970.6 billion. The budget authorization is broken down as follows, Proposals to reorganize the Department go back many decades, the Economic Development Administration would be completely eliminated. The Obama administration projects that the reorganization would save $3 billion, the National Oceanic and Atmospheric Administration would be transferred from the Department of Commerce into the Department of the Interior. Later that year, shortly before the 2012 presidential election, Obama invoked the idea of a secretary of business in reference to the plan. The reorganization was part of a proposal which would grant the President the authority to propose mergers of federal agencies. This ability had existed from the Great Depression until the Reagan presidency, the Obama administration plan faced criticism for some of its elements.
However, environmental groups such as the Natural Resources Defense Council feared that the reorganization could distract the agency from its mission of protecting the nations oceans, the plan was reiterated in the Obama administrations FY2016 budget proposal that was released in February 2015
This radiation pattern is often described as doughnut shaped. Note that this is different from an antenna, which radiates equal power in all directions and has a spherical radiation pattern. Higher-gain omnidirectional antennas can be built, higher gain in this case means that the antenna radiates less energy at higher and lower elevation angles and more in the horizontal directions. High-gain omnidirectional antennas are generally realized using collinear dipole arrays and these consist of multiple half-wave dipoles mounted collinearly, fed in phase. The coaxial collinear antenna uses transposed coaxial sections to produce in-phase half-wavelength radiators, a Franklin Array uses short U-shaped half-wavelength sections whose radiation cancels in the far-field to bring each half-wavelength dipole section into equal phase. Another type is the Omnidirectional Microstrip Antenna, Omnidirectional radiation patterns are produced by the simplest practical antennas and dipole antennas, consisting of one or two straight rod conductors on a common axis.
Antenna gain is defined as antenna efficiency multiplied by antenna directivity which is expressed mathematically as, G = e D. A useful relationship between omnidirectional radiation pattern directivity in decibels and half-power beamwidth based on the assumption of a sin b θ / b θ pattern shape is, D =10 log 10 d B
Very high frequency
Very high frequency is the ITU designation for the range of radio frequency electromagnetic waves from 30 MHz to 300 MHz, with corresponding wavelengths of ten to one meters. Frequencies immediately below VHF are denoted high frequency, and the higher frequencies are known as ultra high frequency. Air traffic control communications and air navigation systems work at distances of 100 kilometres or more to aircraft at cruising altitude, some older DVB-T receivers included channels E2 to E4 but newer ones only go down to channel E5. VHF propagation characteristics are suited for terrestrial communication, with a range generally somewhat farther than line-of-sight from the transmitter. VHF waves are restricted to the radio horizon less than 100 miles. VHF is less affected by noise and interference from electrical equipment than lower frequencies. Unlike high frequencies, the ionosphere does not usually reflect VHF waves, the distance to the radio horizon is slightly extended over the geometric line of sight to the horizon, as radio waves are weakly bent back toward the Earth by the atmosphere.
These approximations are only valid for antennas at heights that are compared to the radius of the Earth. They may not necessarily be accurate in mountainous areas, since the landscape may not be transparent enough for radio waves, in engineered communications systems, more complex calculations are required to assess the probable coverage area of a proposed transmitter station. The accuracy of calculations for digital TV signals is being debated. Portable radios usually use whips or rubber ducky antennas, while base stations usually use larger fiberglass whips or collinear arrays of vertical dipoles, for directional antennas, the Yagi antenna is the most widely used as a high gain or beam antenna. For television reception, the Yagi is used, as well as the log periodic antenna due to its wider bandwidth and turnstile antennas are used for satellite communication since they employ circular polarization. For even higher gain, multiple Yagis or helicals can be mounted together to make array antennas, vertical collinear arrays of dipoles can be used to make high gain omnidirectional antennas, in which more of the antennas power is radiated in horizontal directions.
Television and FM broadcasting stations use arrays of specialized dipole antennas such as batwing antennas. Certain subparts of the VHF band have the same use around the world, some national uses are detailed below. 108–118 MHz, Air navigation beacons VOR and Instrument Landing System localiser, 118–137 MHz, Airband for air traffic control, AM,121.5 MHz is emergency frequency 144–146 MHz, Amateur radio. Other capital cities and regional areas used a combination of these, the initial commercial services in Hobart and Darwin were respectively allocated channels 6 and 8 rather than 7 or 9. By the early 1960s it became apparent that the 10 VHF channels were insufficient to support the growth of television services and this was rectified by the addition of three additional frequencies—channels 0, 5A and 11
Weather forecasting is the application of science and technology to predict the state of the atmosphere for a given location. Human beings have attempted to predict the weather informally for millennia, forecasts become less accurate as the difference between current time and the time for which the forecast is being made increases. The use of ensembles and model consensus help narrow the error, there are a variety of end uses to weather forecasts. Weather warnings are important forecasts because they are used to protect life, forecasts based on temperature and precipitation are important to agriculture, and therefore to traders within commodity markets. Temperature forecasts are used by utility companies to estimate demand over coming days, on an everyday basis, people use weather forecasts to determine what to wear on a given day. Since outdoor activities are severely curtailed by rain and wind chill, forecasts can be used to plan activities around these events. In 2014, the US spent $5.1 billion on weather forecasting, for millennia people have tried to forecast the weather.
In 650 BC, the Babylonians predicted the weather from cloud patterns as well as astrology, in about 340 BC, Aristotle described weather patterns in Meteorologica. Later, Theophrastus compiled a book on weather forecasting, called the Book of Signs, chinese weather prediction lore extends at least as far back as 300 BC, which was around the same time ancient Indian astronomers developed weather-prediction methods. You know how to interpret the appearance of the sky, ancient weather forecasting methods usually relied on observed patterns of events, termed pattern recognition. For example, it might be observed if the sunset was particularly red. This experience accumulated over the generations to produce weather lore, not all of these predictions prove reliable, and many of them have since been found not to stand up to rigorous statistical testing. It was not until the invention of the telegraph in 1835 that the modern age of weather forecasting began. Before that, the fastest that distant weather reports could travel was around 100 miles per day, the two men credited with the birth of forecasting as a science were officer of the Royal Navy Francis Beaufort and his protégé Robert FitzRoy.
Beaufort developed the Wind Force Scale and Weather Notation coding, which he was to use in his journals for the remainder of his life. He promoted the development of reliable tide tables around British shores, Robert FitzRoy was appointed in 1854 as chief of a new department within the Board of Trade to deal with the collection of weather data at sea as a service to mariners. This was the forerunner of the modern Meteorological Office, all ship captains were tasked with collating data on the weather and computing it, with the use of tested instruments that were loaned for this purpose. Fifteen land stations were established to use the new telegraph to transmit to him daily reports of weather at set times leading to the first gale warning service and his warning service for shipping was initiated in February 1861, with the use of telegraph communications
Europe is a continent that comprises the westernmost part of Eurasia. Europe is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, yet the non-oceanic borders of Europe—a concept dating back to classical antiquity—are arbitrary. Europe covers about 10,180,000 square kilometres, or 2% of the Earths surface, Europe is divided into about fifty sovereign states of which the Russian Federation is the largest and most populous, spanning 39% of the continent and comprising 15% of its population. Europe had a population of about 740 million as of 2015. Further from the sea, seasonal differences are more noticeable than close to the coast, Europe, in particular ancient Greece, was the birthplace of Western civilization. The fall of the Western Roman Empire, during the period, marked the end of ancient history. Renaissance humanism, exploration and science led to the modern era, from the Age of Discovery onwards, Europe played a predominant role in global affairs. Between the 16th and 20th centuries, European powers controlled at times the Americas, most of Africa, Oceania.
The Industrial Revolution, which began in Great Britain at the end of the 18th century, gave rise to economic and social change in Western Europe. During the Cold War, Europe was divided along the Iron Curtain between NATO in the west and the Warsaw Pact in the east, until the revolutions of 1989 and fall of the Berlin Wall. In 1955, the Council of Europe was formed following a speech by Sir Winston Churchill and it includes all states except for Belarus and Vatican City. Further European integration by some states led to the formation of the European Union, the EU originated in Western Europe but has been expanding eastward since the fall of the Soviet Union in 1991. The European Anthem is Ode to Joy and states celebrate peace, in classical Greek mythology, Europa is the name of either a Phoenician princess or of a queen of Crete. The name contains the elements εὐρύς, broad and ὤψ eye, broad has been an epithet of Earth herself in the reconstructed Proto-Indo-European religion and the poetry devoted to it.
For the second part the divine attributes of grey-eyed Athena or ox-eyed Hera. The same naming motive according to cartographic convention appears in Greek Ανατολή, Martin Litchfield West stated that phonologically, the match between Europas name and any form of the Semitic word is very poor. Next to these there is a Proto-Indo-European root *h1regʷos, meaning darkness. Most major world languages use words derived from Eurṓpē or Europa to refer to the continent, in some Turkic languages the originally Persian name Frangistan is used casually in referring to much of Europe, besides official names such as Avrupa or Evropa
Herbert Clark Hoover was an American politician who served as the 31st President of the United States from 1929 to 1933 during the Great Depression. He was defeated in a landslide in 1932 by Democrat Franklin D, a lifelong Quaker, he became a successful mining engineer around the globe and retired in 1912. In the First World War he built a reputation as a humanitarian by leading relief efforts in Belgium during the war. He headed the U. S. Food Administration during World War I and his reputation as a Progressive businessman fighting for efficiency and elimination of waste was built as the Secretary of Commerce 1921-28. Hoover was a leader in the Efficiency Movement, which held that every institution public and they all could be improved by experts who could identify the problems and solve them. He believed in the importance of volunteerism and of the role of individuals in society, in the presidential election of 1928, Hoover easily won the Republican nomination, despite having no elected-office experience.
Although Hoover never raised the issue, some of his supporters did in mobilizing anti-Catholic sentiment against his opponent Al Smith. He reluctantly approved the Smoot–Hawley Tariff of 1930, which sent foreign trade spiralling down and he believed it was essential to balance the budget despite falling tax revenue, so he raised the tax rates. The economy kept falling, and the unemployment rate rose to 25%, with industry, mining. This downward spiral, plus his support for policies that had lost favor, set the stage for Hoovers overwhelming defeat in 1932 by Democrat Franklin D. Roosevelt. Most historians agree that Hoovers defeat in the 1932 election was caused primarily by the downward economic spiral, Hoover became a conservative spokesman for opposition to the domestic and foreign policies of the New Deal. He opposed entry into the Second World War and was not given any role to play, in 1946, President Harry S. Truman liked Hoover and appointed him to survey war-torn Germany which produced a number of reports that changed U. S. occupation policy.
In 1947, Truman appointed Hoover to head the Hoover Commission, by the time of his death, he had rehabilitated his image. Nevertheless, Hoover is often ranked by historians as one of the worst U. S. presidents. Herbert Hoover was born on August 10,1874, in West Branch, Iowa, he would become the only President so far born in that state and the first born west of the Mississippi River. His father, Jesse Hoover, was a blacksmith and farm implement store owner, of German, German-Swiss, Jesse Hoover and his father Eli had moved to Iowa from Ohio twenty years previously. Hoovers mother, Hulda Randall Minthorn, was born in Norwich, Canada, both of his parents were Quakers. At about age two he contracted the croup and he was so ill that he was momentarily thought to have died, until he was resuscitated by his uncle, John Minthorn
BBC Radio 5 Live
BBC Radio 5 Live is the BBCs national radio service that specialises in live BBC News, phone-ins and sports commentaries. It is the radio station covering sport in the United Kingdom. Radio 5 Live was launched in March 1994 as a repositioning of the original Radio 5 and it is transmitted via analogue radio in AM on medium wave 693 and 909 kHz and digitally via digital radio and via an Internet stream. Due to rights restrictions, coverage of events is not available on-line or is restricted to UK addresses. The station broadcasts from MediaCityUK in Salford and is a department of the BBC North division, the success of Radio 4 News FM during the first Gulf War led the BBC to propose the launch a rolling-news service. The new BBC Radio 5 Live began its 24-hour service at 05,00 on Monday 28 March 1994, the first voice on air, Jane Garvey, went on to co-present the breakfast and drive-time shows with Peter Allen. The Times described the launch as slipp smoothly and confidently into a routine of informative banter, the news of the first day was dominated by the fatal stabbing at Hall Garth School in Cleveland, the first of many major incidents which the network covered live as they unfolded.
The tone of the channel and more relaxed than contemporary BBC output, was the key to the channels success, the first audiences were some four million, with a record audience of six and a quarter million. In 2000, the station was rebranded with a new logo which would remain with the station for seven years. The station began to further its boundaries with the publication of the Radio Five Live Sporting Yearbook. In August 2007, BBC Radio 5 Live was given a new logo in line with the rest of the BBC Radio network, in 2008 the BBC announced that the station would move to MediaCityUK in Salford. Uniquely to the BBC Radio network, it is the station that is neither purely digital nor broadcast in analogue FM. The station broadcasts programmes live through the BBC Online website and the BBC iPlayer sub-site, the service is available on the Radioplayer internet site partially run by the BBC. Before the launch of digital broadcasting, BBC Radio 5 Live had broadcast on analogue satellite with near-FM quality.
However, as part of the plan to sell off Television Centre. The move itself began in September 2011 and took two months, the new studios occupy a single floor in Quay House, with two studios large enough for several guests and a separate studio for large groups. BBC Radio 5 Lives remit includes broadcasting rolling news and transmitting news as it breaks, the BBCs policy for major breaking news events revolves around a priority list. With UK news, the correspondent first records a generic minute summary, the subsequent priority is to report on Radio 5 Live, the BBC News Channel, and any other programmes that are on air
Digital audio broadcasting
Digital audio broadcasting is a digital radio standard for broadcasting digital audio radio services, used in several countries across Europe and Asia Pacific. The DAB standard was initiated as a European research project in the 1980s, the Norwegian Broadcasting Corporation launched the first DAB channel in the world on 1 June 1995, and the BBC and Swedish Radio launched their first DAB digital radio broadcasts in September 1995. DAB receivers have been available in many countries since the end of the 1990s, DAB may offer more radio programmes over a specific spectrum than analogue FM radio. Audio quality varies depending on the used and audio material. Most stations use a bit rate of 128 kbit/s or less with the MP2 audio codec, which requires 160 kbit/s to achieve perceived FM quality. 128 kbit/s gives better dynamic range or signal-to-noise ratio than FM radio, but a more smeared stereo image, however, CD quality sound with MP2 is possible with 256…192 kbps. An upgraded version of the system was released in February 2007, DAB is not forward compatible with DAB+, which means that DAB-only receivers are not able to receive DAB+ broadcasts.
However, broadcasters can mix DAB and DAB+ programs inside the same transmission, DAB+ is approximately twice as efficient as DAB, and more robust. In spectrum management, the bands that are allocated for public DAB services, are abbreviated with T-DAB, where the T stands for terrestrial. More than 30 countries provide DAB transmissions, and several countries, such as Norway, UK, Italy, Switzerland, The Netherlands, in many countries it is expected that DAB will gradually replace FM radio. Norway was the first country to announce national FM radio analog switchoff starting from 2017, DAB has been under development since 1981 at the Institut für Rundfunktechnik. In 1985 the first DAB demonstrations were held at the WARC-ORB in Geneva, DAB was developed as a research project for the European Union, which started in 1987 on initiative by a consortium formed in 1986. The MPEG-1 Audio Layer II codec was created as part of the EU147 project, a choice of audio codec and error-correction coding schemes and first trial broadcasts were made in 1990.
Public demonstrations were made in 1993 in the United Kingdom, the protocol specification was finalized in 1993 and adopted by the ITU-R standardization body in 1994, the European community in 1995 and by ETSI in 1997. Pilot broadcasts were launched in countries in 1995. The UK was the first country to receive a range of radio stations via DAB. Commercial DAB receivers began to be sold in 1999 and over 50 commercial, the standard was coordinated by the European DAB forum, formed in 1995 and reconstituted to the World DAB Forum in 1997, which represents more than 30 countries. In 2006 the World DAB Forum became the World DMB Forum which now presides over both the DAB and DMB standard, in October 2005, the World DMB Forum instructed its Technical Committee to carry out the work needed to adopt the AAC+ audio codec and stronger error correction coding
In radio, written as long wave or long-wave, and commonly abbreviated LW, refers to parts of the radio spectrum with relatively long wavelengths. The term is an one, dating from the early 20th century, when the radio spectrum was considered to consist of long, medium. Most modern radio systems and devices use wavelengths which would have been considered ultra-short, in contemporary usage, the term longwave is not defined precisely, and its meaning varies across the world. Sometimes, part of the frequency band is included. The International Telecommunication Union Region 1 longwave broadcast band falls wholly within the low band of the radio spectrum. Broader definitions of longwave may extend below and/or above it, in the US, the Longwave Club of America is interested in frequencies below the AM broadcast band, i. e. all frequencies below 535 kHz. Because of their wavelength, radio waves in this frequency range can diffract over obstacles like mountain ranges and travel beyond the horizon. This mode of propagation, called ground wave, is the mode in the longwave band.
The attenuation of signal strength with distance by absorption in the ground is lower than at higher frequencies, Low frequency ground waves can be received up to 2,000 kilometres from the transmitting antenna. Low frequency waves can travel long distances by reflecting from the ionosphere, although this method. Reflection occurs at the ionospheric E layer or F layers, skywave signals can be detected at distances exceeding 300 kilometres from the transmitting antenna. Non-directional beacons transmit continuously for the benefit of radio direction finders in marine and they identify themselves by a callsign in Morse code. They can occupy any frequency in the range 190–1750 kHz, in North America, they occupy 190–535 kHz. In ITU Region 1 the lower limit is 280 kHz, there are government broadcast stations in the range 40–80 kHz that transmit coded time signals to radio clocks. Radio controlled clocks receive their time calibration signals with built-in long-wave receivers, long-waves travel by groundwaves that hug the surface of the earth, unlike medium-waves and short-waves.
Those higher-frequency signals do not follow the surface of the Earth beyond a few kilometers and these different propagation paths can make the time lag different for every signal received. The military of the United Kingdom, Russian Federation, United States, Germany, in North America during the 1970s, the frequencies 167,179 and 191 kHz were assigned to the short-lived Public Emergency Radio of the United States. Nowadays, in the United States, Part 15 of FCC regulations allow unlicensed use of 136 kHz and this is called Low Frequency Experimental Radio
Poland, officially the Republic of Poland, is a country in Central Europe, situated between the Baltic Sea in the north and two mountain ranges in the south. Bordered by Germany to the west, the Czech Republic and Slovakia to the south and Belarus to the east, the total area of Poland is 312,679 square kilometres, making it the 69th largest country in the world and the 9th largest in Europe. With a population of over 38.5 million people, Poland is the 34th most populous country in the world, the 8th most populous country in Europe, Poland is a unitary state divided into 16 administrative subdivisions, and its capital and largest city is Warsaw. Other metropolises include Kraków, Wrocław, Poznań, Gdańsk and Szczecin, the establishment of a Polish state can be traced back to 966, when Mieszko I, ruler of a territory roughly coextensive with that of present-day Poland, converted to Christianity. The Kingdom of Poland was founded in 1025, and in 1569 it cemented a political association with the Grand Duchy of Lithuania by signing the Union of Lublin.
This union formed the Polish–Lithuanian Commonwealth, one of the largest and most populous countries of 16th and 17th century Europe, Poland regained its independence in 1918 at the end of World War I, reconstituting much of its historical territory as the Second Polish Republic. In September 1939, World War II started with the invasion of Poland by Nazi Germany, followed thereafter by invasion by the Soviet Union. More than six million Polish citizens died in the war, after the war, Polands borders were shifted westwards under the terms of the Potsdam Conference. With the backing of the Soviet Union, a communist puppet government was formed, and after a referendum in 1946. During the Revolutions of 1989 Polands Communist government was overthrown and Poland adopted a new constitution establishing itself as a democracy, informally called the Third Polish Republic. Since the early 1990s, when the transition to a primarily market-based economy began, Poland has achieved a high ranking on the Human Development Index.
Poland is a country, which was categorised by the World Bank as having a high-income economy. Furthermore, it is visited by approximately 16 million tourists every year, Poland is the eighth largest economy in the European Union and was the 6th fastest growing economy on the continent between 2010 and 2015. According to the Global Peace Index for 2014, Poland is ranked 19th in the list of the safest countries in the world to live in. The origin of the name Poland derives from a West Slavic tribe of Polans that inhabited the Warta River basin of the historic Greater Poland region in the 8th century, the origin of the name Polanie itself derives from the western Slavic word pole. In some foreign languages such as Hungarian, Lithuanian and Turkish the exonym for Poland is Lechites, historians have postulated that throughout Late Antiquity, many distinct ethnic groups populated the regions of what is now Poland. The most famous archaeological find from the prehistory and protohistory of Poland is the Biskupin fortified settlement, dating from the Lusatian culture of the early Iron Age, the Slavic groups who would form Poland migrated to these areas in the second half of the 5th century AD.
With the Baptism of Poland the Polish rulers accepted Christianity and the authority of the Roman Church
The human voice consists of sound made by a human being using the vocal folds for talking, laughing, screaming, etc. The human voice frequency is specifically a part of sound production in which the vocal folds are the primary sound source. Generally speaking, the mechanism for generating the human voice can be subdivided into three parts, the lungs, the vocal folds within the larynx, and the articulators, the lung must produce adequate airflow and air pressure to vibrate vocal folds. The vocal folds are a vibrating valve that chops up the airflow from the lungs into audible pulses that form the sound source. The muscles of the larynx adjust the length and tension of the folds to ‘fine-tune’ pitch. The articulators articulate and filter the sound emanating from the larynx, the vocal folds, in combination with the articulators, are capable of producing highly intricate arrays of sound. The tone of voice may be modulated to suggest emotions such as anger, singers use the human voice as an instrument for creating music.
Adult men and women typically have different sizes of vocal fold, adult male voices are usually lower-pitched and have larger folds. The male vocal folds, are between 17 mm and 25 mm in length, the female vocal folds are between 12.5 mm and 17.5 mm in length. The folds are within the larynx and they are attached at the back to the arytenoids cartilages, and at the front to the thyroid cartilage. They have no outer edge as they blend into the side of the tube while their inner edges or margins are free to vibrate. They have a three layer construction of an epithelium, vocal ligament, which can shorten and they are flat triangular bands and are pearly white in color. Above both sides of the cord is the vestibular fold or false vocal cord, which has a small sac between its two folds. The difference in vocal folds size between men and women means that they have differently pitched voices, genetics causes variances amongst the same sex, with mens and womens singing voices being categorized into types.
For example, among men, there are bass, baritone and countertenor, there are additional categories for operatic voices, see voice type. This is not the source of difference between male and female voice. Men, generally speaking, have a vocal tract, which essentially gives the resultant voice a lower-sounding timbre. This is mostly independent of the folds themselves
The ionosphere is a region of Earths upper atmosphere, from about 60 km to 1,000 km altitude, and includes the thermosphere and parts of the mesosphere and exosphere. It is ionized by radiation, plays an important part in atmospheric electricity. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth. The ionosphere is a shell of electrons and electrically charged atoms and molecules that surrounds the Earth and it owes its existence primarily to ultraviolet radiation from the Sun. The lowest part of the Earths atmosphere, the troposphere extends from the surface to about 10 km, above 10 km is the stratosphere, followed by the mesosphere. In the stratosphere incoming solar radiation creates the ozone layer, at heights of above 80 km, in the thermosphere, the atmosphere is so thin that free electrons can exist for short periods of time before they are captured by a nearby positive ion. The number of free electrons is sufficient to affect radio propagation.
This portion of the atmosphere is ionized and contains a plasma which is referred to as the ionosphere, in this process the light electron obtains a high velocity so that the temperature of the created electronic gas is much higher than the one of ions and neutrals. The reverse process to ionization is recombination, in which an electron is captured by a positive ion. Recombination occurs spontaneously, and causes the emission of a photon carrying away the energy produced upon recombination, as gas density increases at lower altitudes, the recombination process prevails, since the gas molecules and ions are closer together. The balance between two processes determines the quantity of ionization present. Ionization depends primarily on the Sun and its activity, the amount of ionization in the ionosphere varies greatly with the amount of radiation received from the Sun. Thus there is an effect and a seasonal effect. The local winter hemisphere is tipped away from the Sun, thus there is less received solar radiation, the activity of the Sun is associated with the sunspot cycle, with more radiation occurring with more sunspots.
Radiation received varies with geographical location, there are mechanisms that disturb the ionosphere and decrease the ionization. There are disturbances such as flares and the associated release of charged particles into the solar wind which reaches the Earth. At night the F layer is the layer of significant ionization present. During the day, the D and E layers become more heavily ionized, as does the F layer