105-497: TIROS-1 (or TIROS-A ) was the first full-scale weather satellite (the Vanguard 2 satellite was the first experimental/prototype weather satellite), the first of a series of Television Infrared Observation Satellites (TIROS) placed in low Earth orbit . The TIROS Program was NASA's first experimental step to determine if satellites could be useful in the study of the Earth. At that time,
210-401: A geomagnetic storm temporarily enlarges the auroral oval. Large geomagnetic storms are most common during the peak of the 11-year sunspot cycle or during the three years after the peak. An electron spirals (gyrates) about a field line at an angle that is determined by its velocity vectors, parallel and perpendicular, respectively, to the local geomagnetic field vector B. This angle is known as
315-581: A more intense storm). Infrared pictures depict ocean eddies or vortices and map currents such as the Gulf Stream which are valuable to the shipping industry. Fishermen and farmers are interested in knowing land and water temperatures to protect their crops against frost or increase their catch from the sea. Even El Niño phenomena can be spotted. Using color-digitized techniques, the gray shaded thermal images can be converted to color for easier identification of desired information. Each meteorological satellite
420-713: A much better resolution than their geostationary counterparts due their closeness to the Earth. The United States has the NOAA series of polar orbiting meteorological satellites, presently NOAA-15, NOAA-18 and NOAA-19 ( POES ) and NOAA-20 and NOAA-21 ( JPSS ). Europe has the Metop -A, Metop -B and Metop -C satellites operated by EUMETSAT . Russia has the Meteor and RESURS series of satellites. China has FY -3A, 3B and 3C. India has polar orbiting satellites as well. The United States Department of Defense 's Meteorological Satellite ( DMSP ) can "see"
525-447: A number of changes over its predecessors in support of its mission to gather data for weather forecasting and climate monitoring. The MTG satellites are three-axis stabilised rather than spin stabilised, giving greater flexibility in satellite and instrument design. The MTG system features separate Imager and Sounder satellite models that share the same satellite bus, with a baseline of three satellites - two Imagers and one Sounder - forming
630-432: A particle depends on the particle's pitch angle : the angle between its direction of motion and the local magnetic field. An aurora is created by processes that decrease the pitch angle of many individual electrons, freeing them from the magnetic trap and causing them to hit the atmosphere. In the case of diffuse auroras, the electron pitch angles are altered by their interaction with various plasma waves . Each interaction
735-705: A scatterometer and a radio-occultation instrument. The satellite service module is based on the SPOT-5 bus, while the payload suite is a combination of new and heritage instruments from both Europe and the US under the Initial Joint Polar System agreement between EUMETSAT and NOAA. A second generation of Metop satellites ( MetOp-SG ) is in advanced development with launch of the first satellite foreseen in 2025. As with MTG, Metop-SG will launch on Ariane-6 and comprise two satellite models to be operated in pairs in replacement of
840-515: A second imager satellite will operate from 9.5-deg East to perform a Rapid Scanning mission over Europe. MTG continues Meteosat support to the ARGOS and Search and Rescue missions. MTG-I1 launched in one of the last Ariane-5 launches, with the subsequent satellites planned to launch in Ariane-6 when it enters service. In 2006, the first European low-Earth orbit operational meteorological satellite, Metop -A
945-510: A southward component of the IMF, which can then directly connect to the high latitude geomagnetic field lines. The flow pattern of magnetospheric plasma is mainly from the magnetotail toward Earth, around Earth and back into the solar wind through the magnetopause on the day-side. In addition to moving perpendicular to Earth's magnetic field, some magnetospheric plasma travels down along Earth's magnetic field lines, gains additional energy and loses it to
1050-502: A trained analyst to determine cloud heights and types, to calculate land and surface water temperatures, and to locate ocean surface features. Infrared satellite imagery can be used effectively for tropical cyclones with a visible eye pattern, using the Dvorak technique , where the difference between the temperature of the warm eye and the surrounding cold cloud tops can be used to determine its intensity (colder cloud tops generally indicate
1155-462: A valuable asset in such situations. Nighttime photos also show the burn-off in gas and oil fields. Atmospheric temperature and moisture profiles have been taken by weather satellites since 1969. Not all weather satellites are direct imagers . Some satellites are sounders that take measurements of a single pixel at a time. They have no horizontal spatial resolution but often are capable or resolving vertical atmospheric layers . Soundings along
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#17328523317451260-501: A velocity typically around 400 km/s, a density of around 5 ions/cm and a magnetic field intensity of around 2–5 nT (for comparison, Earth's surface field is typically 30,000–50,000 nT). During magnetic storms , in particular, flows can be several times faster; the interplanetary magnetic field (IMF) may also be much stronger. Joan Feynman deduced in the 1970s that the long-term averages of solar wind speed correlated with geomagnetic activity. Her work resulted from data collected by
1365-595: A weak glow (often deep red) observed around the two polar cusps, the field lines separating the ones that close through Earth from those that are swept into the tail and close remotely. Early work on the imaging of the auroras was done in 1949 by the University of Saskatchewan using the SCR-270 radar. The altitudes where auroral emissions occur were revealed by Carl Størmer and his colleagues, who used cameras to triangulate more than 12,000 auroras. They discovered that most of
1470-535: A year. These factors combined can lead to minor cyclical changes in the detailed way that the IMF links to the magnetosphere. In turn, this affects the average probability of opening a door through which energy from the solar wind can reach Earth's inner magnetosphere and thereby enhance auroras. Recent evidence in 2021 has shown that individual separate substorms may in fact be correlated networked communities. Just as there are many types of aurora, there are many different mechanisms that accelerate auroral particles into
1575-718: Is a type of Earth observation satellite that is primarily used to monitor the weather and climate of the Earth. Satellites can be polar orbiting (covering the entire Earth asynchronously), or geostationary (hovering over the same spot on the equator ). While primarily used to detect the development and movement of storm systems and other cloud patterns, meteorological satellites can also detect other phenomena such as city lights, fires, effects of pollution, auroras , sand and dust storms , snow cover, ice mapping, boundaries of ocean currents , and energy flows. Other types of environmental information are collected using weather satellites. Weather satellite images helped in monitoring
1680-509: Is classified in accordance with ITU Radio Regulations (article 1) as follows: Fixed service (article 1.20) The allocation of radio frequencies is provided according to Article 5 of the ITU Radio Regulations (edition 2012). In order to improve harmonisation in spectrum utilisation, the majority of service-allocations stipulated in this document were incorporated in national Tables of Frequency Allocations and Utilisations which
1785-446: Is designed to use one of two different classes of orbit: geostationary and polar orbiting . Geostationary weather satellites orbit the Earth above the equator at altitudes of 35,880 km (22,300 miles). Because of this orbit , they remain stationary with respect to the rotating Earth and thus can record or transmit images of the entire hemisphere below continuously with their visible-light and infrared sensors. The news media use
1890-443: Is essentially wave-particle scattering ; the electron energy after interacting with the wave is similar to its energy before interaction, but the direction of motion is altered. If the final direction of motion after scattering is close to the field line (specifically, if it falls within the loss cone ) then the electron will hit the atmosphere. Diffuse auroras are caused by the collective effect of many such scattered electrons hitting
1995-444: Is generally accompanied by decreasing peak emission heights of about 8 km for blue and green emissions and above average solar wind speeds ( c. 500 km/s ). In addition, the aurora and associated currents produce a strong radio emission around 150 kHz known as auroral kilometric radiation (AKR), discovered in 1972. Ionospheric absorption makes AKR only observable from space. X-ray emissions, originating from
2100-520: Is induced within the conductor. The strength of the current depends on a) the rate of relative motion, b) the strength of the magnetic field, c) the number of conductors ganged together and d) the distance between the conductor and the magnetic field, while the direction of flow is dependent upon the direction of relative motion. Dynamos make use of this basic process ("the dynamo effect "), any and all conductors, solid or otherwise are so affected, including plasmas and other fluids. The IMF originates on
2205-484: Is more effectively transferred by the temporary magnetic connection between the field lines of the solar wind and those of the magnetosphere. Unsurprisingly this process is known as magnetic reconnection . As already mentioned, it happens most readily when the interplanetary field is directed southward, in a similar direction to the geomagnetic field in the inner regions of both the north magnetic pole and south magnetic pole . Auroras are more frequent and brighter during
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#17328523317452310-407: Is regularly derived from ground data and serves as a general measure of auroral activity. Kristian Birkeland deduced that the currents flowed in the east–west directions along the auroral arc, and such currents, flowing from the dayside toward (approximately) midnight were later named "auroral electrojets" (see also Birkeland currents ). Ionosphere can contribute to the formation of auroral arcs via
2415-411: Is what has given humanity the capability to make accurate and preemptive space weather forecasts since the late 2010s. In Europe, the first Meteosat geostationary operational meteorological satellite, Meteosat-1, was launched in 1977 on a Delta launch vehicle. The satellite was a spin-stabilised cylindrical design, 2.1 m in diameter and 3.2 m tall, rotating at approx. 100 rpm and carrying
2520-522: Is why there is a color differential with altitude; at high altitudes oxygen red dominates, then oxygen green and nitrogen blue/purple/red, then finally nitrogen blue/purple/red when collisions prevent oxygen from emitting anything. Green is the most common colour. Then comes pink, a mixture of light green and red, followed by pure red, then yellow (a mixture of red and green), and finally, pure blue. Precipitating protons generally produce optical emissions as incident hydrogen atoms after gaining electrons from
2625-468: Is with-in the responsibility of the appropriate national administration. The allocation might be primary, secondary, exclusive, and shared. Auroral light An aurora ( pl. aurorae or auroras ), also commonly known as the northern lights ( aurora borealis ) or southern lights ( aurora australis ), is a natural light display in Earth 's sky, predominantly seen in high-latitude regions (around
2730-468: The Arctic and Antarctic ). Auroras display dynamic patterns of brilliant lights that appear as curtains, rays, spirals, or dynamic flickers covering the entire sky. Auroras are the result of disturbances in the Earth's magnetosphere caused by the solar wind . Major disturbances result from enhancements in the speed of the solar wind from coronal holes and coronal mass ejections . These disturbances alter
2835-541: The COSPAS-SARSAT Search and Rescue (SAR) and ARGOS Data Collection Platform (DCP) missions. SEVIRI provided an increased number of spectral channels over MVIRI and imaged the full-Earth disc at double the rate. Meteosat-9 was launched to complement Meteosat-8 in 2005, with the second pair consisting of Meteosat-10 and Meteosat-11 launched in 2012 and 2015, respectively. The Meteosat Third Generation (MTG) programme launched its first satellite in 2022, and featured
2940-571: The European Commission 's Copernicus programme and fulfils the Sentinel-4 mission to monitor air quality, trace gases and aerosols over Europe hourly at high spatial resolution. Two MTG satellites - one Imager and one Sounder - will operate in close proximity from the 0-deg geostationary location over western Africa to observe the eastern Atlantic Ocean, Europe, Africa and the Middle East, while
3045-476: The Explorer 33 spacecraft. The solar wind and magnetosphere consist of plasma (ionized gas), which conducts electricity. It is well known (since Michael Faraday 's work around 1830) that when an electrical conductor is placed within a magnetic field while relative motion occurs in a direction that the conductor cuts across (or is cut by ), rather than along , the lines of the magnetic field, an electric current
3150-956: The Meteosat Visible and Infrared Imager (MVIRI) instrument. Successive Meteosat first generation satellites were launched, on European Ariane-4 launchers from Kourou in French Guyana, up to and including Meteosat-7 which acquired data from 1997 until 2017, operated initially by the European Space Agency and later by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). Japan has launched nine Himawari satellites beginning in 1977. Starting in 1988 China has launched twenty-one Fengyun satellites. The Meteosat Second Generation (MSG) satellites - also spin stabilised although physically larger and twice
3255-464: The feedback instability under high ionospheric resistance conditions, observed at night time and in dark Winter hemisphere. Earth is constantly immersed in the solar wind , a flow of magnetized hot plasma (a gas of free electrons and positive ions) emitted by the Sun in all directions, a result of the two-million-degree temperature of the Sun's outermost layer, the corona . The solar wind reaches Earth with
TIROS-1 - Misplaced Pages Continue
3360-411: The mesosphere in presence of electron precipitation . Horse-collar auroras (HCA) are auroral features in which the auroral ellipse shifts poleward during the dawn and dusk portions and the polar cap becomes teardrop-shaped. They form during periods when the interplanetary magnetic field (IMF) is permanently northward, when the IMF clock angle is small. Their formation is associated with the closure of
3465-521: The solar radiation balance of the tropics. Other dust storms in Asia and mainland China are common and easy to spot and monitor, with recent examples of dust moving across the Pacific Ocean and reaching North America. In remote areas of the world with few local observers, fires could rage out of control for days or even weeks and consume huge areas before authorities are alerted. Weather satellites can be
3570-444: The watersheds of the western United States. This information is gleaned from existing satellites of all agencies of the U.S. government (in addition to local, on-the-ground measurements). Ice floes, packs, and bergs can also be located and tracked from weather spacecraft. Even pollution whether it is nature-made or human-made can be pinpointed. The visual and infrared photos show effects of pollution from their respective areas over
3675-455: The "pitch angle" of the particle. The distance, or radius, of the electron from the field line at any time is known as its Larmor radius. The pitch angle increases as the electron travels to a region of greater field strength nearer to the atmosphere. Thus, it is possible for some particles to return, or mirror, if the angle becomes 90° before entering the atmosphere to collide with the denser molecules there. Other particles that do not mirror enter
3780-409: The 1960s by many research teams using rockets and satellites to traverse the auroral zone. The main findings have been that auroral arcs and other bright forms are due to electrons that have been accelerated during the final few 10,000 km or so of their plunge into the atmosphere. These electrons often, but not always, exhibit a peak in their energy distribution, and are preferentially aligned along
3885-526: The 1962 Defense Satellite Applications Program (DSAP) and the 1964 Soviet Meteor series . TIROS paved the way for the Nimbus program , whose technology and findings are the heritage of most of the Earth-observing satellites NASA and NOAA have launched since then. Beginning with the Nimbus 3 satellite in 1969, temperature information through the tropospheric column began to be retrieved by satellites from
3990-446: The Earth at a typical altitude of 850 km (530 miles) in a north to south (or vice versa) path, passing over the poles in their continuous flight. Polar orbiting weather satellites are in sun-synchronous orbits , which means they are able to observe any place on Earth and will view every location twice each day with the same general lighting conditions due to the near-constant local solar time . Polar orbiting weather satellites offer
4095-813: The Indian Ocean. The Japanese have the MTSAT -2 located over the mid Pacific at 145°E and the Himawari 8 at 140°E. The Europeans have four in operation, Meteosat -8 (3.5°W) and Meteosat-9 (0°) over the Atlantic Ocean and have Meteosat-6 (63°E) and Meteosat-7 (57.5°E) over the Indian Ocean. China currently has four Fengyun (风云) geostationary satellites (FY-2E at 86.5°E, FY-2F at 123.5°E, FY-2G at 105°E and FY-4A at 104.5 °E) operated. India also operates geostationary satellites called INSAT which carry instruments for meteorological purposes. Polar orbiting weather satellites circle
4200-508: The Roman goddess of the dawn, Aurora , who travelled from east to west announcing the coming of the Sun . Ancient Greek poets used the corresponding name " Eos " metaphorically to refer to dawn, often mentioning its play of colours across the otherwise dark sky (e.g., "rosy-fingered dawn"). The words borealis and australis are derived from the names of the ancient gods of the north wind ( Boreas ) and
4305-515: The Sun, linked to the sunspots , and its field lines (lines of force) are dragged out by the solar wind. That alone would tend to line them up in the Sun-Earth direction, but the rotation of the Sun angles them at Earth by about 45 degrees forming a spiral in the ecliptic plane, known as the Parker spiral . The field lines passing Earth are therefore usually linked to those near the western edge ("limb") of
TIROS-1 - Misplaced Pages Continue
4410-521: The U.S., Europe, India, China, Russia, and Japan provide nearly continuous observations for a global weather watch. As early as 1946, the idea of cameras in orbit to observe the weather was being developed. This was due to sparse data observation coverage and the expense of using cloud cameras on rockets. By 1958, the early prototypes for TIROS and Vanguard (developed by the Army Signal Corps ) were created. The first weather satellite, Vanguard 2 ,
4515-570: The amount of acceleration imparted to the precipitating particles. Most of the planets in the Solar System , some natural satellites , brown dwarfs , and even comets also host auroras. The term aurora borealis was coined by Galileo in 1619, from the Roman Aurora, goddess of the dawn , and the Greek Boreas, god of the cold north wind . The word aurora is derived from the name of
4620-486: The atmosphere and contribute to the auroral display over a range of altitudes. Other types of auroras have been observed from space; for example, "poleward arcs" stretching sunward across the polar cap, the related "theta aurora", and "dayside arcs" near noon. These are relatively infrequent and poorly understood. Other interesting effects occur such as pulsating aurora, "black aurora" and their rarer companion "anti-black aurora" and subvisual red arcs. In addition to all these,
4725-423: The atmosphere in the auroral zones. The cusps of the magnetosphere, separating geomagnetic field lines that close through Earth from those that close remotely allow a small amount of solar wind to directly reach the top of the atmosphere, producing an auroral glow. On 26 February 2008, THEMIS probes were able to determine, for the first time, the triggering event for the onset of magnetospheric substorms . Two of
4830-456: The atmosphere. Electron aurora in Earth's auroral zone (i.e. commonly visible aurora) can be split into two main categories with different immediate causes: diffuse and discrete aurora. Diffuse aurora appear relatively structureless to an observer on the ground, with indistinct edges and amorphous forms. Discrete aurora are structured into distinct features with well-defined edges such as arcs, rays and coronas; they also tend to be much brighter than
4935-447: The atmosphere. Proton auroras are usually observed at lower latitudes. Bright auroras are generally associated with Birkeland currents (Schield et al., 1969; Zmuda and Armstrong, 1973 ), which flow down into the ionosphere on one side of the pole and out on the other. In between, some of the current connects directly through the ionospheric E layer (125 km); the rest ("region 2") detours, leaving again through field lines closer to
5040-439: The atmosphere. The process is mediated by the plasma waves, which become stronger during periods of high geomagnetic activity , leading to increased diffuse aurora at those times. In the case of discrete auroras, the trapped electrons are accelerated toward Earth by electric fields that form at an altitude of about 4000–12000 km in the "auroral acceleration region". The electric fields point away from Earth (i.e. upward) along
5145-708: The aurora borealis and changes simultaneously with changes in the northern auroral zone. The aurora australis is visible from high southern latitudes in Antarctica , the Southern Cone , South Africa , Australasia and under exceptional circumstances as far north as Uruguay . The aurora borealis is visible from areas around the Arctic such as Alaska , Canada , Iceland , Greenland , the Faroe Islands , Scandinavia , Finland , Scotland , and Russia . A geomagnetic storm causes
5250-518: The auroral oval to active displays along the darkside and after 1–3 hours they gradually change back. Changes in auroras over time are commonly visualized using keograms . At shorter time scales, auroras can change their appearances and intensity, sometimes so slowly as to be difficult to notice, and at other times rapidly down to the sub-second scale. The phenomenon of pulsating auroras is an example of intensity variations over short timescales, typically with periods of 2–20 seconds. This type of aurora
5355-650: The auroral ovals (north and south) to expand, bringing the aurora to lower latitudes. On rare occasions, the aurora borealis can be seen as far south as the Mediterranean and the southern states of the US while the aurora australis can be seen as far north as New Caledonia and the Pilbara region in Western Australia . During the Carrington Event , the greatest geomagnetic storm ever observed, auroras were seen even in
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#17328523317455460-412: The background magnetic field (comparable to the electron inertial length or ion gyroradius ), Alfvén waves develop a significant electric field parallel to the background magnetic field. This electric field can accelerate electrons to keV energies, significant to produce auroral arcs. If the electrons have a speed close to that of the wave's phase velocity, they are accelerated in a manner analogous to
5565-584: The best of all weather vehicles with its ability to detect objects almost as 'small' as a huge oil tanker . In addition, of all the weather satellites in orbit, only DMSP can "see" at night in the visual. Some of the most spectacular photos have been recorded by the night visual sensor; city lights, volcanoes , fires, lightning, meteors , oil field burn-offs, as well as the Aurora Borealis and Aurora Australis have been captured by this 720 kilometres (450 mi) high space vehicle's low moonlight sensor. At
5670-465: The collision of particles precipitated into the atmosphere. Both incoming electrons and protons may be involved. Excitation energy is lost within the atmosphere by the emission of a photon, or by collision with another atom or molecule: Oxygen is unusual in terms of its return to ground state: it can take 0.7 seconds to emit the 557.7 nm green light and up to two minutes for the red 630.0 nm emission. Collisions with other atoms or molecules absorb
5775-414: The cover assembly and by 21 nickel-cadmium batteries . A single monopole antenna for reception of ground commands extended out from the top of the cover assembly. A pair of crossed-dipole antennas (235 MHz) for transmission projected down and diagonally out from the baseplate. Mounted around the edge of the baseplate were five diametrically opposed pairs of small, solid-fuel thrusters that maintained
5880-468: The currents are the direct result of electron acceleration into the atmosphere by wave/particle interactions. Ionospheric resistance has a complex nature, and leads to a secondary Hall current flow. By a strange twist of physics, the magnetic disturbance on the ground due to the main current almost cancels out, so most of the observed effect of auroras is due to a secondary current, the auroral electrojet . An auroral electrojet index (measured in nanotesla)
5985-441: The development of a meteorological satellite information system. Weather forecasting was deemed the most promising application of space-based observations. TIROS 1 was an 18-sided right prism , 107 centimetres (42 in) across opposite corners and 56 centimetres (22 in) high. Spacecraft power was supplied by approximately 9000 1 centimetre (0.39 in)- by 2 centimetres (0.79 in) silicon solar cells mounted on
6090-416: The diffuse aurora. In both cases, the electrons that eventually cause the aurora start out as electrons trapped by the magnetic field in Earth's magnetosphere . These trapped particles bounce back and forth along magnetic field lines and are prevented from hitting the atmosphere by the magnetic mirror formed by the increasing magnetic field strength closer to Earth. The magnetic mirror's ability to trap
6195-404: The dune aurora phenomenon was discovered by Finnish citizen scientists . It consists of regularly-spaced, parallel stripes of brighter emission in the green diffuse aurora which give the impression of sand dunes. The phenomenon is believed to be caused by the modulation of atomic oxygen density by a large-scale atmospheric wave travelling horizontally in a waveguide through an inversion layer in
6300-571: The eastern Atlantic and most of the Pacific Ocean, which led to significant improvements to weather forecasts . The ESSA and NOAA polar orbiting satellites followed suit from the late 1960s onward. Geostationary satellites followed, beginning with the ATS and SMS series in the late 1960s and early 1970s, then continuing with the GOES series from the 1970s onward. Polar orbiting satellites such as QuikScat and TRMM began to relay wind information near
6405-458: The effectiveness of satellite observations was still unproven. Since satellites were a new technology, the TIROS Program also tested various design issues for spacecraft: instruments, data and operational parameters. The goal was to improve satellite applications for Earth-bound decisions, such as "should we evacuate the coast because of the hurricane ?". The TIROS-1 Program's first priority was
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#17328523317456510-458: The electric field increases the kinetic energy of all of the electrons transiting downward through the acceleration region by the same amount. This accelerates electrons starting from the magnetosphere with initially low energies (tens of eV or less) to energies required to create an aurora (100s of eV or greater), allowing that large source of particles to contribute to creating auroral light. The accelerated electrons carry an electric current along
6615-694: The entire earth. Aircraft and rocket pollution, as well as condensation trails , can also be spotted. The ocean current and low level wind information gleaned from the space photos can help predict oceanic oil spill coverage and movement. Almost every summer, sand and dust from the Sahara Desert in Africa drifts across the equatorial regions of the Atlantic Ocean. GOES-EAST photos enable meteorologists to observe, track and forecast this sand cloud. In addition to reducing visibilities and causing respiratory problems, sand clouds suppress hurricane formation by modifying
6720-454: The equator and closing through the "partial ring current" carried by magnetically trapped plasma. The ionosphere is an ohmic conductor , so some consider that such currents require a driving voltage, which an, as yet unspecified, dynamo mechanism can supply. Electric field probes in orbit above the polar cap suggest voltages of the order of 40,000 volts, rising up to more than 200,000 volts during intense magnetic storms. In another interpretation,
6825-490: The excitation energy and prevent emission; this process is called collisional quenching . Because the highest parts of the atmosphere contain a higher percentage of oxygen and lower particle densities, such collisions are rare enough to allow time for oxygen to emit red light. Collisions become more frequent progressing down into the atmosphere due to increasing density, so that red emissions do not have time to happen, and eventually, even green light emissions are prevented. This
6930-628: The first long-term observations of a developing storm from orbit, tracking the disintegration of a large cyclonic mass off the coast of Bermuda over the course of four days. In addition, TIROS 1 returned data on smaller scale structures such as tornadoes and jet streams , and findings returned from the satellite complemented and enhanced ground-based findings. TIROS 1 performed normally from launch until June 15, 1960, when an electrical power failure prevented further useful TV transmission. As of 2024, TIROS 1 remains in orbit. Weather satellite A weather satellite or meteorological satellite
7035-461: The five probes, positioned approximately one third the distance to the Moon, measured events suggesting a magnetic reconnection event 96 seconds prior to auroral intensification. Geomagnetic storms that ignite auroras may occur more often during the months around the equinoxes . It is not well understood, but geomagnetic storms may vary with Earth's seasons. Two factors to consider are the tilt of both
7140-500: The geostationary photos in their daily weather presentation as single images or made into movie loops. These are also available on the city forecast pages of www.noaa.gov (example Dallas, TX). Several geostationary meteorological spacecraft are in operation. The United States' GOES series has three in operation: GOES-15 , GOES-16 and GOES-17 . GOES-16 and-17 remain stationary over the Atlantic and Pacific Oceans, respectively. GOES-15
7245-430: The intense phase of the solar cycle when coronal mass ejections increase the intensity of the solar wind. Earth's magnetosphere is shaped by the impact of the solar wind on Earth's magnetic field. This forms an obstacle to the flow, diverting it, at an average distance of about 70,000 km (11 Earth radii or Re), producing a bow shock 12,000 km to 15,000 km (1.9 to 2.4 Re) further upstream. The width of
7350-401: The interaction of the solar wind with Earth's magnetosphere . The varying intensity of the solar wind produces effects of different magnitudes but includes one or more of the following physical scenarios. The details of these phenomena are not fully understood. However, it is clear that the prime source of auroral particles is the solar wind feeding the magnetosphere, the reservoir containing
7455-509: The light is produced between 90 and 150 km (56 and 93 mi) above the ground, while extending at times to more than 1,000 km (620 mi). According to Clark (2007), there are five main forms that can be seen from the ground, from least to most visible: Brekke (1994) also described some auroras as "curtains". The similarity to curtains is often enhanced by folds within the arcs. Arcs can fragment or break up into separate, at times rapidly changing, often rayed features that may fill
7560-762: The local direction of the magnetic field. Electrons mainly responsible for diffuse and pulsating auroras have, in contrast, a smoothly falling energy distribution, and an angular (pitch-angle) distribution favouring directions perpendicular to the local magnetic field. Pulsations were discovered to originate at or close to the equatorial crossing point of auroral zone magnetic field lines. Protons are also associated with auroras, both discrete and diffuse. Auroras result from emissions of photons in Earth's upper atmosphere , above 80 km (50 mi), from ionized nitrogen atoms regaining an electron, and oxygen atoms and nitrogen based molecules returning from an excited state to ground state . They are ionized or excited by
7665-426: The magnetic field line. Electrons moving downward through these fields gain a substantial amount of energy (on the order of a few keV ) in the direction along the magnetic field line toward Earth. This field-aligned acceleration decreases the pitch angle for all of the electrons passing through the region, causing many of them to hit the upper atmosphere. In contrast to the scattering process leading to diffuse auroras,
7770-432: The magnetic field lines (a Birkeland current ). Since the electric field points in the same direction as the current, there is a net conversion of electromagnetic energy into particle energy in the auroral acceleration region (an electric load ). The energy to power this load is eventually supplied by the magnetized solar wind flowing around the obstacle of Earth's magnetic field, although exactly how that power flows through
7875-422: The magnetic flux at the top of the dayside magnetosphere by the double lobe reconnection (DLR). There are approximately 8 HCA events per month, with no seasonal dependence, and that the IMF must be within 30 degrees of northwards. Conjugate auroras are nearly exact mirror-image auroras found at conjugate points in the northern and southern hemispheres on the same geomagnetic field lines. These generally happen at
7980-413: The magnetosphere abreast of Earth is typically 190,000 km (30 Re), and on the night side a long "magnetotail" of stretched field lines extends to great distances (> 200 Re). The high latitude magnetosphere is filled with plasma as the solar wind passes Earth. The flow of plasma into the magnetosphere increases with additional turbulence, density, and speed in the solar wind. This flow is favoured by
8085-490: The magnetosphere is still an active area of research. While the energy to power the aurora is ultimately derived from the solar wind, the electrons themselves do not travel directly from the solar wind into Earth's auroral zone; magnetic field lines from these regions do not connect to the solar wind, so there is no direct access for solar wind electrons. Some auroral features are also created by electrons accelerated by dispersive Alfvén waves . At small wavelengths transverse to
8190-650: The mass of the first generation - were developed by ESA with European industry and in cooperation with EUMETSAT who then operate the satellites from their headquarters in Darmstadt, Germany with this same approach followed for all subsequent European meteorological satellites. Meteosat-8 , the first MSG satellite, was launched in 2002 on an Ariane-5 launcher, carrying the Spinning Enhanced Visible and Infrared Imager (SEVIRI) and Geostationary Earth Radiation Budget (GERB) instruments, along with payloads to support
8295-503: The most dramatic photos showed the 600 Kuwaiti oil fires that the fleeing Army of Iraq started on February 23, 1991. The night photos showed huge flashes, far outstripping the glow of large populated areas. The fires consumed huge quantities of oil; the last was doused on November 6, 1991. Snowfield monitoring, especially in the Sierra Nevada , can be helpful to the hydrologist keeping track of available snowpack for runoff vital to
8400-433: The noon direction and 23° away in the midnight direction. The peak equatorward extent of the oval is displaced slightly from geographic midnight. It is centered about 3–5° nightward of the magnetic pole, so that auroral arcs reach furthest toward the equator when the magnetic pole in question is in between the observer and the Sun , which is called magnetic midnight . Early evidence for a geomagnetic connection comes from
8505-484: The ocean's surface starting in the late 1970s, with microwave imagery which resembled radar displays, which significantly improved the diagnoses of tropical cyclone strength, intensification, and location during the 2000s and 2010s. The DSCOVR satellite, owned by NOAA, was launched in 2015 and became the first deep space satellite that can observe and predict space weather. It can detect potentially dangerous weather such as solar wind and geomagnetic storms . This
8610-529: The operational configuration. The imager satellites carry the Flexible Combined Imager (FCI), succeeding MVIRI and SEVIRI to give even greater resolution and spectral coverage, scanning the full Earth disc every ten minutes, as well as a new Lightning Imager (LI) payload. The sounder satellites carry the Infrared Sounder (IRS) and Ultra-violet Visible Near-infrared (UVN) instruments. UVN is part of
8715-498: The opposite order. Until about 1963, it was thought that these changes are due to the rotation of the Earth under a pattern fixed with respect to the Sun. Later, it was found by comparing all-sky films of auroras from different places (collected during the International Geophysical Year ) that they often undergo global changes in a process called auroral substorm . They change in a few minutes from quiet arcs all along
8820-456: The particles associated with auroras, have also been detected. Aurora noise , similar to a crackling noise, begins about 70 m (230 ft) above Earth's surface and is caused by charged particles in an inversion layer of the atmosphere formed during a cold night. The charged particles discharge when particles from the Sun hit the inversion layer, creating the noise. In 2016, more than fifty citizen science observations described what
8925-589: The radiation zones and temporarily magnetically trapped particles confined by the geomagnetic field, coupled with particle acceleration processes. The immediate cause of the ionization and excitation of atmospheric constituents leading to auroral emissions was discovered in 1960, when a pioneering rocket flight from Fort Churchill in Canada revealed a flux of electrons entering the atmosphere from above. Since then an extensive collection of measurements has been acquired painstakingly and with steadily improving resolution since
9030-431: The ribbon). The processes that cause STEVE are also associated with a picket-fence aurora, although the latter can be seen without STEVE. It is an aurora because it is caused by precipitation of electrons in the atmosphere but it appears outside the auroral oval, closer to the equator than typical auroras. When the picket-fence aurora appears with STEVE, it is below. First reported in 2020, and confirmed in 2021,
9135-424: The same time, energy use and city growth can be monitored since both major and even minor cities, as well as highway lights, are conspicuous. This informs astronomers of light pollution . The New York City Blackout of 1977 was captured by one of the night orbiter DMSP space vehicles. In addition to monitoring city lights, these photos are a life saving asset in the detection and monitoring of fires. Not only do
9240-582: The satellite ground track can still be gridded later to form maps . According to the International Telecommunication Union (ITU), a meteorological-satellite service (also: meteorological-satellite radiocommunication service ) is – according to Article 1.52 of the ITU Radio Regulations (RR) – defined as « An earth exploration-satellite service for meteorological purposes.» This radiocommunication service
9345-407: The satellite spin rate between 8 and 12 rpm. The satellite was equipped with two 1.27 centimetres (0.50 in)-diameter vidicon TV cameras , one wide angle and one narrow angle, for taking earth cloud cover pictures. The pictures were transmitted directly to a ground receiving station or were stored in a magnetic tape recorder on board for later playback, depending on whether the satellite
9450-429: The satellites see the fires visually day and night, but the thermal and infrared scanners on board these weather satellites detect potential fire sources below the surface of the Earth where smoldering occurs. Once the fire is detected, the same weather satellites provide vital information about wind that could fan or spread the fires. These same cloud photos from space tell the firefighter when it will rain. Some of
9555-782: The single first generation satellites to continue the EPS mission. Observation is typically made via different 'channels' of the electromagnetic spectrum , in particular, the visible and infrared portions. Some of these channels include: Visible-light images from weather satellites during local daylight hours are easy to interpret even by the average person, clouds, cloud systems such as fronts and tropical storms, lakes, forests, mountains, snow ice, fires, and pollution such as smoke, smog, dust and haze are readily apparent. Even wind can be determined by cloud patterns, alignments and movement from successive photos. The thermal or infrared images recorded by sensors called scanning radiometers enable
9660-416: The solar and Earth's axis to the ecliptic plane. As Earth orbits throughout a year, it experiences an interplanetary magnetic field (IMF) from different latitudes of the Sun, which is tilted at 8 degrees. Similarly, the 23-degree tilt of Earth's axis about which the geomagnetic pole rotates with a diurnal variation changes the daily average angle that the geomagnetic field presents to the incident IMF throughout
9765-454: The south wind ( Auster ) in Greco-Roman mythology . Auroras are most commonly observed in the "auroral zone", a band approximately 6° (~660 km) wide in latitude centered on 67° north and south. The region that currently displays an aurora is called the "auroral oval". The oval is displaced by the solar wind, pushing it about 15° away from the geomagnetic pole (not the geographic pole) in
9870-402: The statistics of auroral observations. Elias Loomis (1860), and later Hermann Fritz (1881) and Sophus Tromholt (1881) in more detail, established that the aurora appeared mainly in the auroral zone. In northern latitudes , the effect is known as the aurora borealis or the northern lights. The southern counterpart, the aurora australis or the southern lights, has features almost identical to
9975-409: The time of the equinoxes , when there is little difference in the orientation of the north and south geomagnetic poles to the sun. Attempts were made to image conjugate auroras by aircraft from Alaska and New Zealand in 1967, 1968, 1970, and 1971, with some success. A full understanding of the physical processes which lead to different types of auroras is still incomplete, but the basic cause involves
10080-402: The trajectories of charged particles in the magnetospheric plasma . These particles, mainly electrons and protons , precipitate into the upper atmosphere ( thermosphere / exosphere ). The resulting ionization and excitation of atmospheric constituents emit light of varying colour and complexity. The form of the aurora, occurring within bands around both polar regions, is also dependent on
10185-414: The tropics. Auroras seen within the auroral oval may be directly overhead. From farther away, they illuminate the poleward horizon as a greenish glow, or sometimes a faint red, as if the Sun were rising from an unusual direction. Auroras also occur poleward of the auroral zone as either diffuse patches or arcs, which can be subvisual. Auroras are occasionally seen in latitudes below the auroral zone, when
10290-406: The visible Sun at any time. The solar wind and the magnetosphere, being two electrically conducting fluids in relative motion, should be able in principle to generate electric currents by dynamo action and impart energy from the flow of the solar wind. However, this process is hampered by the fact that plasmas conduct readily along magnetic field lines, but less readily perpendicular to them. Energy
10395-399: The volcanic ash cloud from Mount St. Helens and activity from other volcanoes such as Mount Etna . Smoke from fires in the western United States such as Colorado and Utah have also been monitored. El Niño and its effects on weather are monitored daily from satellite images. The Antarctic ozone hole is mapped from weather satellite data. Collectively, weather satellites flown by
10500-506: The whole sky. These are also known as discrete auroras , which are at times bright enough to read a newspaper by at night. These forms are consistent with auroras being shaped by Earth's magnetic field. The appearances of arcs, rays, curtains, and coronas are determined by the shapes of the luminous parts of the atmosphere and a viewer's position . Auroras change with time. Over the night they begin with glows and progress toward coronas, although they may not reach them. They tend to fade in
10605-586: Was launched into a Sun-synchronous orbit at 817 km altitude by a Soyuz launcher from Baikonur, Kazakhstan. This operational satellite - which forms the space segment of the EUMETSAT Polar System (EPS) - built on the heritage from ESA's ERS and Envisat experimental missions, and was followed at six-year intervals by Metop-B and Metop-C - the latter launched from French Guyana in a "Europeanised" Soyuz . Each carry thirteen different passive and active instruments ranging in design from imagers and sounders to
10710-550: Was launched on February 17, 1959. It was designed to measure cloud cover and resistance, but a poor axis of rotation and its elliptical orbit kept it from collecting a notable amount of useful data. The Explorer 6 and Explorer 7 satellites also contained weather-related experiments. The first weather satellite to be considered a success was TIROS-1 , launched by NASA on April 1, 1960. TIROS operated for 78 days and proved to be much more successful than Vanguard 2. Other early weather satellite programs include
10815-522: Was retired in early July 2019. The satellite GOES 13 that was previously owned by the National Oceanic and Atmospheric Association (NOAA) was transferred to the U.S. Space Force in 2019 and renamed the EWS-G1; becoming the first geostationary weather satellite to be owned and operated by the U.S. Department of Defense. Russia 's new-generation weather satellite Elektro-L No.1 operates at 76°E over
10920-424: Was to them an unknown type of aurora which they named " STEVE ", for "Strong Thermal Emission Velocity Enhancement". STEVE is not an aurora but is caused by a 25 km (16 mi) wide ribbon of hot plasma at an altitude of 450 km (280 mi), with a temperature of 3,000 °C (3,270 K; 5,430 °F) and flowing at a speed of 6 km/s (3.7 mi/s) (compared to 10 m/s (33 ft/s) outside
11025-514: Was within or beyond the communication range of the station. The satellite was spin-stabilized . Launched into orbit from Cape Canaveral Space Launch Complex 17A on 1 Apr 1960 at 11:40:09 UTC by a Thor Able II rocket. Over its 2 + 1 ⁄ 2 -month lifespan, TIROS 1 returned 23,000 photos of the Earth, 19,000 of them usable for weather analysis. For the first time, it was possible to view large scale cloud patterns in their totality, and from this, identify storm regions. The satellite provided
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