Space weather
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Space weather is a branch of space physics and
aeronomy Aeronomy is the scientific study of the upper atmosphere of the Earth and corresponding regions of the atmospheres of other planets. It is a branch of both atmospheric chemistry and atmospheric physics. Scientists specializing in aeronomy, known a ...
, or
heliophysics Heliophysics (from the prefix " helio", from Attic Greek ''hḗlios'', meaning Sun, and the noun "physics": the science of matter and energy and their interactions) is the physics of the Sun and its connection with the Solar System. NASA define ...
, concerned with the time varying conditions within the Solar System, including the
solar wind The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between . The composition of the sol ...
, emphasizing the space surrounding the Earth, including conditions in the magnetosphere, ionosphere,
thermosphere The thermosphere is the layer in the Earth's atmosphere directly above the mesosphere and below the exosphere. Within this layer of the atmosphere, ultraviolet radiation causes photoionization/photodissociation of molecules, creating ions; the ...
, and exosphere. Space weather is distinct from, but conceptually related to, the terrestrial
weather Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloud cover, cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmos ...
of the
atmosphere of Earth The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing fo ...
(
troposphere The troposphere is the first and lowest layer of the atmosphere of the Earth, and contains 75% of the total mass of the planetary atmosphere, 99% of the total mass of water vapour and aerosols, and is where most weather phenomena occur. From ...
and stratosphere). The term "space weather" was first used in the 1950s and came into common usage in the 1990s. Later, it was generalized to a " space climate" research discipline, which focuses on general behaviors of longer and larger-scale variabilities and effects.


History

For many centuries, the effects of space weather were noticed, but not understood. Displays of auroral light have long been observed at high latitudes.


Genesis

In 1724,
George Graham George Graham (born 30 November 1944), nicknamed "Stroller", is a Scottish former Association football, football player and manager (association football), manager. In his successful playing career, he made 455 appearances in England's Football ...
reported that the needle of a
magnetic compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with ...
was regularly deflected from
magnetic north The north magnetic pole, also known as the magnetic north pole, is a point on the surface of Earth's Northern Hemisphere at which the planet's magnetic field points vertically downward (in other words, if a magnetic compass needle is allowed t ...
over the course of each day. This effect was eventually attributed to overhead electric currents flowing in the ionosphere and magnetosphere by
Balfour Stewart Balfour Stewart (1 November 182819 December 1887) was a Scottish physicist and meteorologist. His studies in the field of radiant heat led to him receiving the Rumford Medal of the Royal Society in 1868. In 1859 he was appointed director of K ...
in 1882, and confirmed by
Arthur Schuster Sir Franz Arthur Friedrich Schuster (12 September 1851 – 14 October 1934) was a German-born British physicist known for his work in spectroscopy, electrochemistry, optics, X-radiography and the application of harmonic analysis to physics. ...
in 1889 from analysis of magnetic observatory data. In 1852, astronomer and British Major General
Edward Sabine Sir Edward Sabine ( ; 14 October 1788 – 26 June 1883) was an Irish astronomer, geophysicist, ornithologist, explorer, soldier and the 30th president of the Royal Society. He led the effort to establish a system of magnetic observatories in ...
showed that the probability of the occurrence of magnetic storms on Earth was correlated with the number of sunspots, demonstrating a novel solar–terrestrial interaction. In 1859, a great
magnetic storm A geomagnetic storm, also known as a magnetic storm, is a temporary disturbance of the Earth's magnetosphere caused by a solar wind shock wave and/or cloud of magnetic field that interacts with the Earth's magnetic field. The disturbance that d ...
caused brilliant auroral displays and disrupted global
telegraph Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas p ...
operations.
Richard Christopher Carrington Richard Christopher Carrington (26 May 1826 – 27 November 1875) was an English amateur astronomer whose 1859 astronomical observations demonstrated the existence of solar flares as well as suggesting their electrical influence upon the Eart ...
correctly connected the storm with a
solar flare A solar flare is an intense localized eruption of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and other sol ...
that he had observed the day before in the vicinity of a large sunspot group, demonstrating that specific solar events could affect the Earth.
Kristian Birkeland Kristian Olaf Bernhard Birkeland (13 December 1867 – 15 June 1917) was a Norwegian scientist. He is best remembered for his theories of atmospheric electric currents that elucidated the nature of the aurora borealis. In order to fund his res ...
explained the physics of aurorae by creating artificial ones in his laboratory, and predicted the solar wind. The introduction of radio revealed that periods of extreme static or noise occurred. Severe
radar jamming Radar jamming and deception is a form of electronic countermeasures that intentionally sends out radio frequency signals to interfere with the operation of radar by saturating its receiver with noise or false information. Concepts that blanket the ...
during a large solar event in 1942 led to the discovery of solar radio bursts (radio waves that cover a broad frequency range created by a solar flare), another aspect of space weather.


The 20th century

In the 20th century, the interest in space weather expanded as military and commercial systems came to depend on systems affected by space weather.
Communications satellites A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. C ...
are a vital part of global commerce.
Weather satellite A weather satellite or meteorological satellite 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 ...
systems provide information about terrestrial weather. The signals from satellites of a
global positioning system The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
(GPS) are used in a wide variety of applications. Space weather phenomena can interfere with or damage these satellites or interfere with the radio signals with which they operate. Space weather phenomena can cause damaging surges in long-distance
transmission lines In electrical engineering, a transmission line is a specialized cable or other structure designed to conduct electromagnetic waves in a contained manner. The term applies when the conductors are long enough that the wave nature of the transmis ...
and expose passengers and crew of aircraft travel to radiation, especially on polar routes. The International Geophysical Year increased research into space weather. Ground-based data obtained during IGY demonstrated that the aurorae occurred in an ''auroral oval'', a permanent region of luminescence 15 to 25° in latitude from the magnetic poles and 5 to 20° wide. In 1958, the
Explorer I Explorer 1 was the first satellite launched by the United States in 1958 and was part of the U.S. participation in the International Geophysical Year (IGY). The mission followed the first two satellites the previous year; the Soviet Union ...
satellite discovered the Van Allen belts, regions of radiation particles trapped by the Earth's magnetic field. In January 1959, the
Soviet The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nation ...
satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioi ...
Luna 1 ''Luna 1'', also known as ''Mechta'' (russian: Мечта , '' lit.'': ''Dream''), ''E-1 No.4'' and ''First Lunar Rover'', was the first spacecraft to reach the vicinity of Earth's Moon, and the first spacecraft to be placed in heliocentric or ...
first directly observed the solar wind and measured its strength. A smaller International Heliophysical Year (IHY) occurred in 2007–2008. In 1969,'' INJUN-5'' (or ''Explorer 40'') made the first direct observation of the electric field impressed on the Earth's high-latitude ionosphere by the solar wind. In the early 1970s, Triad data demonstrated that permanent electric currents flowed between the auroral oval and the magnetosphere. The term "space weather" came into usage in the late 1950s as the space age began and satellites began to measure the space environment. The term regained popularity in the 1990s along with the belief that space's impact on human systems demanded a more coordinated research and application framework.


US National Space Weather Program

The purpose of the US National Space Weather Program is to focus research on the needs of the affected commercial and military communities, to connect the research and user communities, to create coordination between operational data centers, and to better define user community needs. NOAA operates the National Weather Service's
Space Weather Prediction Center The Space Weather Prediction Center (SWPC), named the Space Environment Center (SEC) until 2007, is a laboratory and service center of the US National Weather Service (NWS), part of the National Oceanic and Atmospheric Administration (NOAA), loc ...
. The concept was turned into an action plan in 2000, an implementation plan in 2002, an assessment in 2006 and a revised strategic plan in 2010. A revised action plan was scheduled to be released in 2011 followed by a revised implementation plan in 2012.


Phenomena

Within the
Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...
, space weather is influenced by the solar wind and the
interplanetary magnetic field The interplanetary magnetic field (IMF), now more commonly referred to as the heliospheric magnetic field (HMF), is the component of the solar magnetic field that is dragged out from the solar corona by the solar wind flow to fill the Solar Sy ...
carried by the solar wind plasma. A variety of physical phenomena is associated with space weather, including
geomagnetic storm A geomagnetic storm, also known as a magnetic storm, is a temporary disturbance of the Earth's magnetosphere caused by a solar wind shock wave and/or cloud of magnetic field that interacts with the Earth's magnetic field. The disturbance that d ...
s and substorms, energization of the Van Allen radiation belts, ionospheric disturbances and scintillation of satellite-to-ground radio signals and long-range radar signals, aurorae, and
geomagnetically induced current Geomagnetically induced currents (GIC) are electrical currents induced at the Earth's surface by rapid changes in the geomagnetic field caused by space weather events. GICs can affect the normal operation of long electrical conductor systems such a ...
s at Earth's surface.
Coronal mass ejection A coronal mass ejection (CME) is a significant release of plasma and accompanying magnetic field from the Sun's corona into the heliosphere. CMEs are often associated with solar flares and other forms of solar activity, but a broadly accept ...
s are also important drivers of space weather, as they can compress the magnetosphere and trigger geomagnetic storms.
Solar energetic particles Solar energetic particles (SEP), formerly known as solar cosmic rays, are high-energy, charged particles originating in the solar atmosphere and solar wind. They consist of protons, electrons and heavy ions with energies ranging from a few ten ...
(SEP) accelerated by coronal mass ejections or solar flares can trigger
solar particle event In solar physics, a solar particle event (SPE), also known as a solar energetic particle (SEP) event or solar radiation storm, is a solar phenomenon which occurs when particles emitted by the Sun, mostly protons, become accelerated either in th ...
s, a critical driver of human impact space weather, as they can damage electronics onboard spacecraft (e.g. ''
Galaxy 15 Galaxy 15 is an American telecommunications satellite which is owned by Intelsat. It was launched for and originally operated by PanAmSat, and was subsequently transferred to Intelsat when the two companies merged in 2006. It was originally posit ...
'' failure), and threaten the lives of astronauts, as well as increase radiation hazards to high-altitude, high-latitude aviation.


Effects


Spacecraft electronics

Some spacecraft failures can be directly attributed to space weather; many more are thought to have a space weather component. For example, 46 of the 70 failures reported in 2003 occurred during the October 2003 geomagnetic storm. The two most common adverse space weather effects on spacecraft are
radiation damage Radiation damage is the effect of ionizing radiation on physical objects including non-living structural materials. It can be either detrimental or beneficial for materials. Radiobiology is the study of the action of ionizing radiation on livin ...
and spacecraft charging. Radiation (high-energy particles) passes through the skin of the spacecraft and into the electronic components. In most cases, the radiation causes an erroneous signal or changes one bit in memory of a spacecraft's electronics (
single event upset A single-event upset (SEU), also known as a single-event error (SEE), is a change of state caused by one single ionizing particle (ions, electrons, photons...) striking a sensitive node in a live micro-electronic device, such as in a microprocesso ...
s). In a few cases, the radiation destroys a section of the electronics ( single-event latchup). Spacecraft charging is the accumulation of an electrostatic charge on a nonconducting material on the spacecraft's surface by low-energy particles. If enough charge is built up, a discharge (spark) occurs. This can cause an erroneous signal to be detected and acted on by the spacecraft computer. A recent study indicated that spacecraft charging is the predominant space weather effect on spacecraft in geosynchronous orbit.


Spacecraft orbit changes

The orbits of spacecraft in
low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...
(LEO) decay to lower and lower altitudes due to the resistance from the friction between the spacecraft's surface (''i.e. '', drag) and the outer layer of the Earth's atmosphere (or the thermosphere and exosphere). Eventually, a LEO spacecraft falls out of orbit and towards the Earth's surface. Many spacecraft launched in the past few decades have the ability to fire a small rocket to manage their orbits. The rocket can increase altitude to extend lifetime, to direct the re-entry towards a particular (marine) site, or route the satellite to avoid collision with other spacecraft. Such maneuvers require precise information about the orbit. A geomagnetic storm can cause an orbit change over a few days that otherwise would occur over a year or more. The geomagnetic storm adds heat to the thermosphere, causing the thermosphere to expand and rise, increasing the drag on spacecraft. The
2009 satellite collision On February 10, 2009, two communications satellites—the active commercial Iridium 33 and the derelict Russian military Kosmos 2251—accidentally collided at a speed of and an altitude of above the Taymyr Peninsula in Siberia. It was the fi ...
between the ''Iridium 33'' and ''Cosmos 2251'' demonstrated the importance of having precise knowledge of all objects in orbit. ''Iridium 33'' had the capability to maneuver out of the path of ''Cosmos 2251 ''and could have evaded the crash, if a credible collision prediction had been available.


Humans in space

The exposure of a human body to ionizing radiation has the same harmful effects whether the source of the radiation is a medical
X-ray machine An X-ray machine is any machine that involves X-rays. It may consist of an X-ray generator and an X-ray detector. Examples include: *Machines for medical projectional radiography *Machines for computed tomography *Backscatter X-ray machines, used ...
, a nuclear power plant, or radiation in space. The degree of the harmful effect depends on the length of exposure and the radiation's energy density. The ever-present radiation belts extend down to the altitude of crewed spacecraft such as the
International Space Station The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA ( ...
(ISS) and the
Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program ...
, but the amount of exposure is within the acceptable lifetime exposure limit under normal conditions. During a major space weather event that includes an SEP burst, the flux can increase by orders of magnitude. Areas within ISS provide shielding that can keep the total dose within safe limits. For the
Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program ...
, such an event would have required immediate mission termination.


Ground systems


Spacecraft signals

The ionosphere bends radio waves in the same manner that water in a pool bends visible light. When the medium through which such waves travel is disturbed, the light image or radio information is distorted and can become unrecognizable. The degree of distortion (scintillation) of a radio wave by the ionosphere depends on the signal frequency. Radio signals in the VHF band (30 to 300 MHz) can be distorted beyond recognition by a disturbed ionosphere. Radio signals in the UHF band (300 MHz to 3 GHz) transit a disturbed ionosphere, but a receiver may not be able to keep locked to the carrier frequency. GPS uses signals at 1575.42 MHz (L1) and 1227.6 MHz (L2) that can be distorted by a disturbed ionosphere. Space weather events that corrupt GPS signals can significantly impact society. For example, the
Wide Area Augmentation System The Wide Area Augmentation System (WAAS) is an air navigation aid developed by the Federal Aviation Administration to augment the Global Positioning System (GPS), with the goal of improving its accuracy, integrity, and availability. Essentia ...
operated by the US
Federal Aviation Administration The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic ...
(FAA) is used as a navigation tool for North American commercial aviation. It is disabled by every major space weather event. Outages can range from minutes to days. Major space weather events can push the disturbed polar ionosphere 10° to 30° of latitude toward the equator and can cause large ionospheric gradients (changes in density over distance of hundreds of km) at mid and low latitude. Both of these factors can distort GPS signals.


Long-distance radio signals

Radio wave in the HF band (3 to 30 MHz) (also known as the shortwave band) are reflected by the ionosphere. Since the ground also reflects HF waves, a signal can be transmitted around the curvature of the Earth beyond the line of sight. During the 20th century, HF communications was the only method for a ship or aircraft far from land or a base station to communicate. The advent of systems such as
Iridium Iridium is a chemical element with the symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, it is considered the second-densest naturally occurring metal (after osmium) with a density of ...
brought other methods of communications, but HF remains critical for vessels that do not carry the newer equipment and as a critical backup system for others. Space weather events can create irregularities in the ionosphere that scatter HF signals instead of reflecting them, preventing HF communications. At auroral and polar latitudes, small space weather events that occur frequently disrupt HF communications. At mid-latitudes, HF communications are disrupted by solar radio bursts, by X-rays from solar flares (which enhance and disturb the ionospheric D-layer) and by TEC enhancements and irregularities during major geomagnetic storms. Trans polar airline routes are particularly sensitive to space weather, in part because
Federal Aviation Regulations The Federal Aviation Regulations (FARs) are rules prescribed by the Federal Aviation Administration (FAA) governing all aviation activities in the United States. The FARs comprise Title 14 of the Code of Federal Regulations (CFR). A wide variety ...
require reliable communication over the entire flight. Diverting such a flight is estimated to cost about $100,000.


Humans in commercial aviation

The magnetosphere guides cosmic ray and solar energetic particles to polar latitudes, while high-energy charged particles enter the mesosphere, stratosphere, and troposphere. These energetic particles at the top of the atmosphere shatter atmospheric atoms and molecules, creating harmful lower-energy particles that penetrate deep into the atmosphere and create measurable radiation. All aircraft flying above 8 km (26,200 feet) altitude are exposed to these particles. The dose exposure is greater in polar regions than at midlatitude and equatorial regions. Many commercial aircraft fly over the polar region. When a space weather event causes radiation exposure to exceed the safe level set by aviation authorities, the aircraft's flight path is diverted. While the most significant, but highly unlikely, health consequences to atmospheric radiation exposure include death from cancer due to long-term exposure, many lifestyle-degrading and career-impacting cancer forms can also occur. A cancer diagnosis can have significant career impact for a commercial pilot. A cancer diagnosis can ground a pilot temporarily or permanently. International guidelines from the International Commission on Radiological Protection have been developed to mitigate this statistical risk. The ICRP recommends effective dose limits of a 5-year average of 20 mSv per year with no more than 50 mSv in a single year for nonpregnant, occupationally exposed persons, and 1 mSv per year for the general public. Radiation dose limits are not engineering limits. In the U.S., they are treated as an upper limit of acceptability and not a regulatory limit. Measurements of the radiation environment at commercial aircraft altitudes above 8 km (26,000 ft) have historically been done by instruments that record the data on board where the data are then processed later on the ground. However, a system of real-time radiation measurements on-board aircraft has been developed through the NASA Automated Radiation Measurements for Aerospace Safety (ARMAS) program
ARMAS
has flown hundreds of flights since 2013, mostly on research aircraft, and sent the data to the ground through Iridium satellite links. The eventual goal of these types of measurements is to data assimilate them into physics-based global radiation models, e.g., NASA's Nowcast of Atmospheric Ionizing Radiation System

, so as to provide the weather of the radiation environment rather than the climatology.


Ground-induced electric fields

Magnetic storm activity can induce geoelectric fields in the Earth's conducting lithosphere. Corresponding voltage differentials can find their way into electric power grids through ground connections, driving uncontrolled electric currents that interfere with grid operation, damage transformers, trip protective relays, and sometimes cause blackouts. This complicated chain of causes and effects was demonstrated during the magnetic storm of March 1989, which caused the complete collapse of the Hydro-Québec electric-power grid in Canada, temporarily leaving nine million people without electricity. The possible occurrence of an even more intense storm led to operational standards intended to mitigate induction-hazard risks, while reinsurance companies commissioned revised risk assessments.


Geophysical exploration

Air- and ship-borne magnetic surveys can be affected by rapid magnetic field variations during geomagnetic storms. Such storms cause data-interpretation problems because the space weather-related magnetic field changes are similar in magnitude to those of the subsurface crustal magnetic field in the survey area. Accurate geomagnetic storm warnings, including an assessment of storm magnitude and duration, allows for an economic use of survey equipment.


Geophysics and hydrocarbon production

For economic and other reasons, oil and gas production often involves
horizontal drilling Directional drilling (or slant drilling) is the practice of drilling non-vertical bores. It can be broken down into four main groups: oilfield directional drilling, utility installation directional drilling, directional boring (horizontal dir ...
of well paths many kilometers from a single wellhead. Accuracy requirements are strict, due to target size – reservoirs may only be a few tens to hundreds of meters across – and safety, because of the proximity of other boreholes. The most accurate gyroscopic method is expensive, since it can stop drilling for hours. An alternative is to use a magnetic survey, which enables measurement while drilling (MWD). Near real-time magnetic data can be used to correct drilling direction. Magnetic data and space weather forecasts can help to clarify unknown sources of drilling error.


Terrestrial weather

The amount of energy entering the troposphere and stratosphere from space weather phenomena is trivial compared to the solar insolation in the visible and infrared portions of the solar electromagnetic spectrum. Although some linkage between the 11-year sunspot cycle and the Earth's
climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologi ...
has been claimed., this has never been verified. For example, the Maunder minimum, a 70-year period almost devoid of sunspots, has often been suggested to be correlated to a cooler climate, but these correlations have disappeared after deeper studies. The suggested link from changes in cosmic-ray flux cause changes in the amount of cloud formation. did not survive scientific tests. Another suggestion, that variations in the EUV flux subtly influence existing drivers of the climate and tip the balance between
El Niño El Niño (; ; ) is the warm phase of the El Niño–Southern Oscillation (ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (approximately between the International Date ...
/
La Niña La Niña (; ) is an oceanic and atmospheric phenomenon that is the colder counterpart of as part of the broader El Niño–Southern Oscillation (ENSO) climate pattern. The name ''La Niña'' originates from Spanish for "the girl", by an ...
events. collapsed when new research showed this was not possible. As such, a linkage between space weather and the climate has not been demonstrated. In addition, a link has been suggested between high energy charged particles (such as SEPs and
cosmic rays Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our ow ...
) and cloud formation. This is because charged particles interact with the atmosphere to produce
volatiles Volatiles are the group of chemical elements and chemical compounds that can be readily vaporized. In contrast with volatiles, elements and compounds that are not readily vaporized are known as refractory substances. On planet Earth, the term ...
which then condense, creating cloud seeds. This is a topic of ongoing research at CERN, where experiments test the effect of high-energy charged particles on atmosphere. If proven, this may suggest a link between space weather (in the form of
solar particle event In solar physics, a solar particle event (SPE), also known as a solar energetic particle (SEP) event or solar radiation storm, is a solar phenomenon which occurs when particles emitted by the Sun, mostly protons, become accelerated either in th ...
s) and cloud formation.


Observation

Observation of space weather is done both for scientific research and applications. Scientific observation has evolved with the state of knowledge, while application-related observation expanded with the ability to exploit such data.


Ground-based

Space weather is monitored at ground level by observing changes in the Earth's magnetic field over periods of seconds to days, by observing the surface of the Sun, and by observing radio noise created in the Sun's atmosphere. The Sunspot Number (SSN) is the number of sunspots on the Sun's photosphere in visible light on the side of the Sun visible to an Earth observer. The number and total area of sunspots are related to the brightness of the Sun in the
extreme ultraviolet Extreme ultraviolet radiation (EUV or XUV) or high-energy ultraviolet radiation is electromagnetic radiation in the part of the electromagnetic spectrum spanning wavelengths from 124  nm down to 10 nm, and therefore (by the Planck–E ...
(EUV) and X-ray portions of the solar spectrum and to solar activity such as solar flares and coronal mass ejections. The 10.7 cm radio flux (F10.7) is a measurement of RF emissions from the Sun and is roughly correlated with the solar EUV flux. Since this RF emission is easily obtained from the ground and EUV flux is not, this value has been measured and disseminated continuously since 1947. The world standard measurements are made by the
Dominion Radio Astrophysical Observatory The Dominion Radio Astrophysical Observatory is a research facility founded in 1960 and located at Kaleden, British Columbia, Canada. The site houses four radio telescopes: an interferometric radio telescope, a 26-m single-dish antenna, a solar ...
at Penticton, BC, Canada and reported once a day at local noon in solar flux units (10−22W·m−2·Hz−1). F10.7 is archived by the National Geophysical Data Center. Fundamental space weather monitoring data are provided by ground-based magnetometers and magnetic observatories. Magnetic storms were first discovered by ground-based measurement of occasional magnetic disturbance. Ground magnetometer data provide real-time situational awareness for postevent analysis. Magnetic observatories have been in continuous operations for decades to centuries, providing data to inform studies of long-term changes in space climatology. Disturbance storm time index (Dst index) is an estimate of the magnetic field change at the Earth's magnetic equator due to a ring of electric current at and just earthward of the geosynchronous orbit. The index is based on data from four ground-based magnetic observatories between 21° and 33° magnetic latitude during a one-hour period. Stations closer to the magnetic equator are not used due to ionospheric effects. The Dst index is compiled and archived by the World Data Center for Geomagnetism, Kyoto.Geomagnetic Data Service
World Data Center for Geomagnetism, Kyoto
Kp/ap index: 'a' is an index created from the geomagnetic disturbance at one midlatitude (40° to 50° latitude) geomagnetic observatory during a 3-hour period. 'K' is the quasilogarithmic counterpart of the 'a' index. Kp and ap are the average of K and a over 13 geomagnetic observatories to represent planetary-wide geomagnetic disturbances. The Kp/ap index indicates both geomagnetic storms and substorms (auroral disturbance). Kp/ap data are available from 1932 onward. AE index is compiled from geomagnetic disturbances at 12 geomagnetic observatories in and near the auroral zones and is recorded at 1-minute intervals. The public AE index is available with a lag of two to three days that limits its utility for space weather applications. The AE index indicates the intensity of geomagnetic substorms except during a major geomagnetic storm when the auroral zones expand equatorward from the observatories. Radio noise bursts are reported by the Radio Solar Telescope Network to the U.S. Air Force and to NOAA. The radio bursts are associated with solar flare plasma that interacts with the ambient solar atmosphere. The Sun's photosphere is observed continuously for activity that can be the precursors to solar flares and CMEs. The Global Oscillation Network Group (GONG) project monitors both the surface and the interior of the Sun by using
helioseismology Helioseismology, a term coined by Douglas Gough, is the study of the structure and dynamics of the Sun through its oscillations. These are principally caused by sound waves that are continuously driven and damped by convection near the Sun's sur ...
, the study of sound waves propagating through the Sun and observed as ripples on the solar surface. GONG can detect sunspot groups on the far side of the Sun. This ability has recently been verified by visual observations from the '' STEREO'' spacecraft.
Neutron monitor A neutron monitor is a ground-based detector designed to measure the number of high-energy charged particles striking the Earth's atmosphere from outer space. For historical reasons the incoming particles are called "cosmic rays", but in fact they ...
s on the ground indirectly monitor cosmic rays from the Sun and galactic sources. When cosmic rays interact with the atmosphere, atomic interactions occur that cause a shower of lower-energy particles to descend into the atmosphere and to ground level. The presence of cosmic rays in the near-Earth space environment can be detected by monitoring high-energy neutrons at ground level. Small fluxes of cosmic rays are present continuously. Large fluxes are produced by the Sun during events related to energetic solar flares.
Total Electron Content Total electron content (TEC) is an important descriptive quantity for the ionosphere of the Earth. TEC is the total number of electrons integrated between two points, along a tube of one meter squared cross section, i.e., the electron columnar n ...
(TEC) is a measure of the ionosphere over a given location. TEC is the number of electrons in a column one meter square from the base of the ionosphere (around 90 km altitude) to the top of the ionosphere (around 1000 km altitude). Many TEC measurements are made by monitoring the two frequencies transmitted by
GPS The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
spacecraft. Presently, GPS TEC is monitored and distributed in real time from more than 360 stations maintained by agencies in many countries. Geoeffectiveness is a measure of how strongly space weather magnetic fields, such as coronal mass ejections, couple with the Earth's magnetic field. This is determined by the direction of the magnetic field held within the plasma that originates from the Sun. New techniques measuring Faraday rotation in radio waves are in development to measure field direction.


Satellite-based

A host of research spacecraft have explored space weather. The Orbiting Geophysical Observatory series were among the first spacecraft with the mission of analyzing the space environment. Recent spacecraft include the NASA-ESA Solar-Terrestrial Relations Observatory (STEREO) pair of spacecraft launched in 2006 into solar orbit and the
Van Allen Probes The Van Allen Probes, formerly known as the Radiation Belt Storm Probes (RBSP), were two robotic spacecraft that were used to study the Van Allen radiation belts that surround Earth. NASA conducted the Van Allen Probes mission as part of the Li ...
, launched in 2012 into a highly elliptical Earth orbit. The two STEREO spacecraft drift away from the Earth by about 22° per year, one leading and the other trailing the Earth in its orbit. Together they compile information about the solar surface and atmosphere in three dimensions. The Van Allen probes record detailed information about the radiation belts, geomagnetic storms, and the relationship between the two. Some spacecraft with other primary missions have carried auxiliary instruments for solar observation. Among the earliest such spacecraft were the
Applications Technology Satellite The Applications Technology Satellites (ATS) were a series of experimental satellites launched by NASA, under the supervision of, among others, Wernher von Braun. The program was launched in 1966 to test the feasibility of placing a satellite i ...
(ATS) series at GEO that were precursors to the modern
Geostationary Operational Environmental Satellite The Geostationary Operational Environmental Satellite (GOES), operated by the United States' National Oceanic and Atmospheric Administration (NOAA)'s National Environmental Satellite, Data, and Information Service division, supports weather fo ...
(GOES) weather satellite and many communication satellites. The ATS spacecraft carried environmental particle sensors as auxiliary payloads and had their navigational magnetic field sensor used for sensing the environment. Many of the early instruments were research spacecraft that were re-purposed for space weather applications. One of the first of these was the IMP-8 (Interplanetary Monitoring Platform). It orbited the Earth at 35 Earth radii and observed the solar wind for two-thirds of its 12-day orbits from 1973 to 2006. Since the solar wind carries disturbances that affect the magnetosphere and ionosphere, IMP-8 demonstrated the utility of continuous solar wind monitoring. IMP-8 was followed by ISEE-3, which was placed near the Sun-Earth Lagrangian point, 235 Earth radii above the surface (about 1.5 million km, or 924,000 miles) and continuously monitored the solar wind from 1978 to 1982. The next spacecraft to monitor the solar wind at the point was
WIND Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few ho ...
from 1994 to 1998. After April 1998, the WIND spacecraft orbit was changed to circle the Earth and occasionally pass the point. The NASA
Advanced Composition Explorer Advanced Composition Explorer (ACE or Explorer 71) is a NASA Explorer program satellite and space exploration mission to study matter comprising energetic particles from the solar wind, the interplanetary medium, and other sources. Real-tim ...
has monitored the solar wind at the point from 1997 to present. In addition to monitoring the solar wind, monitoring the Sun is important to space weather. Because the solar EUV cannot be monitored from the ground, the joint
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...
-
ESA , owners = , headquarters = Paris, Île-de-France, France , coordinates = , spaceport = Guiana Space Centre , seal = File:ESA emblem seal.png , seal_size = 130px , image = Views in the Main Control Room (120 ...
Solar and Heliospheric Observatory The Solar and Heliospheric Observatory (SOHO) is a European Space Agency (ESA) spacecraft built by a European industrial consortium led by Matra Marconi Space (now Airbus Defence and Space) that was launched on a Lockheed Martin Atlas IIAS lau ...
(SOHO) spacecraft was launched and has provided solar EUV images beginning in 1995. SOHO is a main source of near-real time solar data for both research and space weather prediction and inspired the STEREO mission. The
Yohkoh Yohkoh (, ''Sunbeam'' in Japanese language, Japanese), known before launch as Solar-A, was a Sun, Solar observatory spacecraft of the JAXA, Institute of Space and Astronautical Science (Japan), in collaboration with space agencies in the NASA ...
spacecraft at LEO observed the Sun from 1991 to 2001 in the X-ray portion of the solar spectrum and was useful for both research and space weather prediction. Data from Yohkoh inspired the
Solar X-ray Imager Solar X-ray Imager (SXI) are full-disc X-ray instruments observing the Sun aboard GOES satellites. The SXI on GOES 12 was the first of its kind and allows the U.S. NOAA to better monitor and predict space weather. Operation The Solar X-ray Imager a ...
on GOES. Spacecraft with instruments whose primary purpose is to provide data for space weather predictions and applications include the
Geostationary Operational Environmental Satellite The Geostationary Operational Environmental Satellite (GOES), operated by the United States' National Oceanic and Atmospheric Administration (NOAA)'s National Environmental Satellite, Data, and Information Service division, supports weather fo ...
(GOES) series of spacecraft, the POES series, the DMSP series, and the
Meteosat The Meteosat series of satellites are geostationary meteorological satellites operated by EUMETSAT under the Meteosat Transition Programme (MTP) and the Meteosat Second Generation (MSG) program. The MTP program was established to ensure the ope ...
series. The GOES spacecraft have carried an X-ray sensor (XRS) which measures the flux from the whole solar disk in two bands – 0.05 to 0.4 nm and 0.1 to 0.8 nm – since 1974, an X-ray imager (SXI) since 2004, a magnetometer which measures the distortions of the Earth's magnetic field due to space weather, a whole disk
EUV Extreme ultraviolet radiation (EUV or XUV) or high- energy ultraviolet radiation is electromagnetic radiation in the part of the electromagnetic spectrum spanning wavelengths from 124  nm down to 10 nm, and therefore (by the Planck ...
sensor since 2004, and particle sensors (EPS/HEPAD) which measure ions and electrons in the energy range of 50 keV to 500 MeV. Starting sometime after 2015, the GOES-R generation of GOES spacecraft will replace the SXI with a solar EUV image (SUVI) similar to the one on
SOHO Soho is an area of the City of Westminster, part of the West End of London. Originally a fashionable district for the aristocracy, it has been one of the main entertainment districts in the capital since the 19th century. The area was develo ...
and STEREO and the particle sensor will be augmented with a component to extend the energy range down to 30 eV. The
Deep Space Climate Observatory Deep Space Climate Observatory (DSCOVR; formerly known as Triana, unofficially known as GoreSat) is a National Oceanic and Atmospheric Administration (NOAA) space weather, space climate, and Earth observation satellite. It was launched by Sp ...
(DSCOVR) satellite is a NOAA Earth observation and space weather satellite that launched in February 2015. Among its features is advance warning of coronal mass ejections.


Models

Space weather models are simulations of the space weather environment. Models use sets of mathematical equations to describe physical processes. These models take a limited data set and attempt to describe all or part of the space weather environment in or to predict how weather evolves over time. Early models were heuristic; i.e''., '' they did not directly employ physics. These models take less resources than their more sophisticated descendants. Later models use physics to account for as many phenomena as possible. No model can yet reliably predict the environment from the surface of the Sun to the bottom of the Earth's ionosphere. Space weather models differ from meteorological models in that the amount of input is vastly smaller. A significant portion of space weather model research and development in the past two decades has been done as part of the
Geospace Outer space, commonly shortened to space, is the expanse that exists beyond Earth and its atmosphere and between celestial bodies. Outer space is not completely empty—it is a near-perfect vacuum containing a low density of particles, pred ...
Environmental Model (GEM) program of the
National Science Foundation The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National ...
. The two major modeling centers are the Center for Space Environment Modeling (CSEM) and the Center for Integrated Space weather Modeling (CISM). The
Community Coordinated Modeling Center {{unreferenced, date=February 2009 The Community Coordinated Modeling Center (CCMC) is a collaborative effort between multiple organizations to provide information and models relating to space weather research. The partnership includes resource ...
(CCMC) at the NASA Goddard Space Flight Center is a facility for coordinating the development and testing of research models, for improving and preparing models for use in space weather prediction and application. Modeling techniques include (a)
magnetohydrodynamics Magnetohydrodynamics (MHD; also called magneto-fluid dynamics or hydro­magnetics) is the study of the magnetic properties and behaviour of electrically conducting fluids. Examples of such magneto­fluids include plasmas, liquid metals, ...
, in which the environment is treated as a fluid, (b) particle in cell, in which non-fluid interactions are handled within a cell and then cells are connected to describe the environment, (c) first principles, in which physical processes are in balance (or equilibrium) with one another, (d) semi-static modeling, in which a statistical or empirical relationship is described, or a combination of multiple methods.


Commercial space weather development

During the first decade of the 21st Century, a commercial sector emerged that engaged in space weather, serving agency, academia, commercial and consumer sectors. Space weather providers are typically smaller companies, or small divisions within a larger company, that provide space weather data, models, derivative products and service distribution. The commercial sector includes scientific and engineering researchers as well as users. Activities are primarily directed toward the impacts of space weather upon technology. These include, for example: * Atmospheric drag on LEO satellites caused by energy inputs into the thermosphere from solar UV, FUV, Lyman-alpha,
EUV Extreme ultraviolet radiation (EUV or XUV) or high- energy ultraviolet radiation is electromagnetic radiation in the part of the electromagnetic spectrum spanning wavelengths from 124  nm down to 10 nm, and therefore (by the Planck ...
, XUV, X-ray, and
gamma ray A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...
photons as well as by charged particle precipitation and Joule heating at high latitudes; * Surface and internal charging from increased energetic particle fluxes, leading to effects such as discharges, single event upsets and latch-up, on LEO to GEO satellites; * Disrupted GPS signals caused by ionospheric scintillation leading to increased uncertainty in navigation systems such as aviation's
Wide Area Augmentation System The Wide Area Augmentation System (WAAS) is an air navigation aid developed by the Federal Aviation Administration to augment the Global Positioning System (GPS), with the goal of improving its accuracy, integrity, and availability. Essentia ...
(WAAS); * Lost HF, UHF and L-band radio communications due to ionosphere scintillation, solar flares and geomagnetic storms; * Increased radiation to human tissue and avionics from
galactic cosmic rays Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...
SEP, especially during large solar flares, and possibly bremsstrahlung gamma-rays produced by precipitating radiation belt energetic electrons at altitudes above 8 km; * Increased inaccuracy in surveying and oil/gas exploration that uses the Earth's main magnetic field when it is disturbed by geomagnetic storms; * Loss of power transmission from GIC surges in the electrical power grid and transformer shutdowns during large geomagnetic storms. Many of these disturbances result in societal impacts that account for a significant part of the national GDP. The concept of incentivizing commercial space weather was first suggested by the idea of a Space Weather Economic Innovation Zone discussed by the American Commercial Space Weather Association (ACSWA) in 2015. The establishment of this economic innovation zone would encourage expanded economic activity developing applications to manage the risks space weather and would encourage broader research activities related to space weather by universities. It could encourage U.S. business investment in space weather services and products. It promoted the support of U.S. business innovation in space weather services and products by requiring U.S. government purchases of U.S. built commercial hardware, software, and associated products and services where no suitable government capability pre-exists. It also promoted U.S. built commercial hardware, software, and associated products and services sales to international partners. designate U.S. built commercial hardware, services, and products as “Space Weather Economic Innovation Zone” activities; Finally, it recommended that U.S. built commercial hardware, services, and products be tracked as Space Weather Economic Innovation Zone contributions within agency reports. In 2015 the U.S. Congress bill HR1561 provided groundwork where social and environmental impacts from a Space Weather Economic Innovation Zone could be far-reaching. In 2016, the Space Weather Research and Forecasting Act (S. 2817) was introduced to build on that legacy. Later, in 2017-2018 the HR3086 Bill took these concepts, included the breadth of material from parallel agency studies as part of the OSTP-sponsored Space Weather Action Program (SWAP), and with bicameral and bipartisan support the 116th Congress (2019) is considering passage of the Space Weather Coordination Act (S141, 115th Congress).


American Commercial Space Weather Association

On April 29, 2010, the commercial space weather community created the American Commercial Space Weather Association
ACSWA
an industry association. ACSWA promotes space weather risk mitigation for national infrastructure, economic strength and national security. It seeks to: * provide quality space weather data and services to help mitigate risks to technology; * provide advisory services to government agencies; * provide guidance on the best task division between commercial providers and government agencies; * represent the interests of commercial providers; * represent commercial capabilities in the national and international arena; * develop best-practices. A summary of the broad technical capabilities in space weather that are available from the association can be found on their web site http://www.acswa.us.


Notable events

* On December 21, 1806,
Alexander von Humboldt Friedrich Wilhelm Heinrich Alexander von Humboldt (14 September 17696 May 1859) was a German polymath, geographer, naturalist, explorer, and proponent of Romantic philosophy and science. He was the younger brother of the Prussian minister, ...
observed that his compass had become erratic during a bright auroral event. * The
Solar storm of 1859 The Carrington Event was the most intense geomagnetic storm in recorded history, peaking from 1 to 2 September 1859 during solar cycle 10. It created strong auroral displays that were reported globally and caused sparking and even fires in mu ...
(Carrington Event) caused widespread disruption of telegraph service. * The Aurora of November 17, 1882 disrupted telegraph service. * The May 1921 geomagnetic storm, one of the largest geomagnetic storms disrupted telegraph service and damaged electrical equipment worldwide. * The
Solar storm of August 1972 The solar storms of August 1972 were a historically powerful series of solar storms with intense to extreme solar flare, solar particle event, and geomagnetic storm components in early August 1972, during solar cycle 20. The storm caused widespre ...
, a large SEP event occurred. If astronauts had been in space at the time, the dose could have been life-threatening. * The March 1989 geomagnetic storm included multiple space weather effects: SEP, CME, Forbush decrease, ground level enhancement, geomagnetic storm, etc.. * The 2000 Bastille Day event coincided with exceptionally bright aurora. * April 21, 2002, the Nozomi Mars Probe was hit by a large SEP event that caused large-scale failure. The mission, which was already about 3 years behind schedule, was abandoned in December 2003. * The 2003 Halloween solar storms, a series of coronal mass ejections and solar flares in late October and early November 2003 with associated impacts


See also


Citations


General bibliography

* Daglis, Ioannis A.: ''Effects of Space Weather on Technology Infrastructure.'' Springer, Dordrecht 2005, . * Lilensten, Jean, and Jean Bornarel, ''Space Weather, Environment and Societies'', Springer, . * Moldwin, Mark: ''An Introduction to Space Weather.'' Cambridge Univ. Press, Cambridge 2008, . * Schwenn, Rainer, ''Space Weather''
Living Reviews in Solar Physics
3, (2006), 2
online article


Further reading

* Bothmer, V.; Daglis, I., 2006, ''Space Weather: Physics and Effects'', Springer-Verlag New York, . * Carlowicz, M. J., and R. E. Lopez, 2002, ''Storms from the Sun'', Joseph Henry Press, Washington DC, . * Clark, T. D. G. and E. Clarke, 2001. ''Space weather services for the offshore drilling industry''. ''In Space Weather Workshop: Looking Towards a Future European Space Weather Programme''. ESTEC, ESA WPP-194. * Daglis, I. A. (Editor), 2001, ''Space Storms and Space Weather Hazards'', Springer-Verlag New York, . * Freeman, John W., 2001, ''Storms in Space'', Cambridge University Press, Cambridge, UK, . * Gombosi, Tamas I., Houghton, John T., and Dessler, Alexander J., (Editors), 2006, ''Physics of the Space Environment'', Cambridge University Press, . * Odenwald, S. 2006, ''The 23rd Cycle;Learning to live with a stormy star'', Columbia University Press, . * Reay, S. J., W. Allen, O. Baillie, J. Bowe, E. Clarke, V. Lesur, S. Macmillan, 2005. ''Space weather effects on drilling accuracy in the North Sea''. Annales Geophysicae, Vol. 23, pp. 3081–3088. * Ruffenach, A., 2018, "Enabling Resilient UK Energy Infrastructure: Natural Hazard Characterisation Technical Volumes and Case Studies, Volume 10 - Space Weather"; IMechE, IChemE. * Song, P., Singer, H., and Siscoe, G., (Editors), 2001, ''Space Weather (Geophysical Monograph)'', Union, Washington, D.C, . * * *


External links


Real-time space weather forecast

* * *
Utah State Univ SWC Real-time GAIM Ionosphere - (real-time model of ionosphere)
* Space Weather and Radio Propagation. Live and historical data and images with a perspective on how it affects
radio propagation Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. As a form of electromagnetic radiation, like light waves, radio waves are affect ...
* Latest Data from STEREO, HINODE and SDO (Large bandwidth) * *


Other links


Space Weather FX
- Video podcast series on Space Weather from MIT Haystack Observatory
ESA's Space Weather Site

Space Weather European Network
- (European Space Agency, ESA) * * * * * * * * * *
Q-Up Now (Q-up)
* * * *
Space Weather For Today and Tomorrow (SWFTT)
* * *
Space Weather Today
- Space Weather from Russian Institute for Applied Geophysics {{DEFAULTSORT:Space Weather Space weather, 1950s neologisms Branches of meteorology Planetary science Radio frequency propagation Solar System Space medicine