There are those who seek to prove that the solar variability is the major cause of climate change, an idea that would let humans and their greenhouse gases off the hook. Others are equally evangelical in their assertions that the sun plays only a minuscule role in climate change. If this dispute could be resolved by an experiment, the obvious strategy would be to see what happens when you switch off one potential cause of climate change and leave the other alone.
The extended collapse in solar activity these past two years may be precisely the right sort of test, in that it has significantly changed the amount of solar radiation bombarding our planet. He has studied records covering data stretching back to , and found that severe European winters are much more likely during periods of low solar activity New Scientist , 17 April, p 6. This fits an emerging picture of solar activity giving rise to a small change in the global climate overall, yet large regional effects.
Another example is the Maunder minimum, the period from to during which sunspots virtually disappeared and solar activity plummeted. If a similar spell of solar inactivity were to begin now and continue until , it would mitigate any temperature rise through global warming by 0. A corresponding boost appears to be associated with peaks in solar output. So why does solar activity have these effects? Modellers may already be onto the answer.
More ultraviolet light reaching the stratosphere means more ozone is formed. And more ozone leads to the stratosphere absorbing more ultraviolet light. So in times of heightened solar activity, the stratosphere heats up and this influences the winds in that layer. Enhanced heating of the stratosphere could be behind the heightened effects felt by Europe of changes in solar activity.
Back in , Haigh showed that the temperature of the stratosphere influences the passage of the jet stream, the high-altitude river of air passing from west to east across Europe. The lesson for climate research is clear. In other words, our understanding of global climate change could be skewed by not taking into account solar effects on European weather. Just as one mystery begins to clear, another beckons. Since its launch 15 years ago, the SOHO spacecraft has watched two solar minimums, one complete solar cycle, and parts of two other cycles — the one that ended in and the one that is just stirring.
It might not sound like much, but it is a hugely significant result. Its observations show that the amount of energy the sun puts out varies by around 0. Despite this variation, the TSI has dipped to the same level during the three previous solar minima. Not so during this recent elongated minimum.
Although the observed drop is small, the fact that it has happened at all is unprecedented. His observations were carried out during the Maunder minimum, and he obtained a result larger than modern measurements. Frustratingly the launch, on a Russian Dnepr rocket, is mired in a political disagreement between Russia and neighbouring Kazakhstan. Until the dispute is resolved, the spacecraft must wait. Every day of delay means valuable data being missed as the sun takes steps, however faltering, into the next cycle of activity.
This question is of great importance in understanding the prospects for the occurrence of an Arctic ozone hole in the future. A few research papers have appeared indicating that better inclusion of the stratosphere in numerical forecasting models leads to greater forecasting skill, but there have been no large-scale operational tests of this type.
To make further progress, the effects of inclusion of a realistic stratosphere in numerical weather prediction models have to be better understood. In addition, models must be tested both against each other and against observations. Better observations of water vapor in the upper troposphere and lower stratosphere are also needed.
Both radiative and chemical models require such data. In the following, some key initiatives for the next 15 years are discussed that will enable progress to be made in the research issues identified earlier. These initiatives are organized by scientific area. It should be noted that although they have been listed in specific scientific areas, many of them will also be useful in other areas. In all cases, a strategy that combines observations, laboratory studies, and modeling is needed. The ability to deploy research aircraft in specific regions and to make high-precision and high-data-rate measurements of many atmospheric parameters has led to great advances in understanding.
Unfortunately, these manned aircraft have ceiling limits that are low in the stratosphere, and they are difficult and expensive to deploy in remote regions. It is very important that unmanned aircraft have a defined role in the study of stratospheric chemistry. However, measurements have been limited by the lack of OH observations and the fact that comprehensive chemistry measurements are available for only one Southern Hemisphere winter. The next opportunity for comprehensive stratospheric satellite measurements will be on the EOS mission.
Continued development in this area is needed to make assessments for the future as well as to check that the atmospheric response to current regulations has been as expected. It is this UV flux that is crucial for biological investigations. Yet these characteristics are crucial in considerations of heterogeneous chemistry and radiative transfer. More needs to be done, and these models should be combined with dynamical and heterogeneous models for more realistic characterization of the atmosphere and improved predictive capability.
More realistic treatments of heterogeneous chemistry in atmospheric models are needed. Also, these treatments should be coupled to microphysical models. These models require better treatment of aerosol physics and heterogeneous chemistry, as well as stratosphere-troposphere exchange. Although stratospheric temperature increases with height, the resulting stability of the stratosphere does not bar the exchange of materials such as radioactive particles or ozone-depleting chemicals between the two.
Observational campaigns together with modeling efforts will be necessary to gain the required understanding of these processes. Versions of numerical weather prediction models should be developed that include the stratosphere in a realistic fashion. Retrospective and real-time weather prediction testing are required to see how inclusion of the stratosphere affects the forecasting skill of these models.
Also, models must be carefully intercompared so that the reasons for their different behavior are understood. Both radiative and chemical models require such information. A successful program will provide a much-improved quantitative understanding of the fundamental chemical, dynamical, and radiative processes that influence the physical and chemical behavior of the middle atmosphere.
It will reduce some key uncertainties affecting the behavior of ozone and other chemical constituents in the middle atmosphere, and specifically in the lower stratosphere, where large ozone depletions have been observed. A successful program should also provide the information needed to determine whether it is possible to take measures that would enhance the long-term stability of the ozone layer and the climate of the Earth.
Earth does not exist in an unchanging and benign vacuum. Rather, it is embedded in the dynamic solar wind that fills interplanetary space with a continuous supersonic flow of plasma from the Sun. The interaction of the solar. Spatial and temporal variations in the solar wind outflow, in response to spatial and temporal changes of the Sun's magnetic field, have a profound effect on the magnetosphere. The complex, time-dependent variations of particles and electric and magnetic fields in the solar wind, the magnetosphere, and the ionosphere produced by solar variability are known collectively as "space weather.
It encompasses those regions noted in the introduction to this Disciplinary Assessment that are most sensitive to transient phenomena originating on the Sun. They are physically linked to one another in various ways; this coupling makes space weather intrinsically an interdisciplinary topic. As with lower-atmospheric weather, research on space weather has two main thrusts: 1 a basic research focus to explore and understand the physical processes linking the fundamental elements of the solar-terrestrial system, and 2 an. Relevant to the latter point, various aspects of space weather can have deleterious effects on both ground- and space-based technological assets, as well as on humans operating in space or at high altitudes.
As our reliance on space systems continues to grow, so too does our vulnerability to space weather. The first crude, unmanned satellite was launched about 40 years ago. At present, more than sophisticated satellites are operating at geosynchronous orbit alone, and there is a routine manned presence in low Earth orbit. In the decades ahead, we anticipate many hundreds of technologically advanced satellites operating in space and a nearly continuous manned presence. The effects of space weather on satellite performance and human health are well documented.
Some of these effects are listed in Box II. Ionization by a single energetic heavy ion can randomly change the state of electronic logic circuits and thus place a spacecraft in jeopardy.
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Changes in ionospheric structure can adversely affect critical civilian and federal navigation and communications systems. Astronauts on board the shuttle or space stations and even people on board aircraft in polar routes can be at risk in a radiation environment that changes in response to solar-terrestrial interactions.
Space weather variations also have negative effects at the surface of the Earth. Reliance on large-scale power grids has led to a broad vulnerability to transient electrical currents induced by time-varying magnetic fields in near-Earth space. These vulnerabilities will likely increase as technology advances, as our presence in space intensifies, and as we become dependent on ever more sophisticated systems for communications, navigation, and other critical functions. Our understanding of space weather, our ability to specify its present state, and our ability to predict changes in this state are at a primitive level, perhaps analogous to that of tropospheric meteorology in the early s.
The purpose of the space weather research program is to convert our present fragmentary understanding into a coherent body of knowledge, so that reliable numerical models of the space environment and the changes associated with space weather can be developed. Just as the extension of meteorological capabilities to stratospheric altitudes has been essential for the full exploitation of commercial aviation, so will the application of the meteorological paradigm to space weather be essential for the full exploitation of space technology.
It is critical to recognize that both long-term years and short-term minutes variations are important in this endeavor. These aspects are described below in the context of solar variability and the corresponding changes that occur in the solar wind and in the Earth's magnetosphere, ionosphere, and upper atmosphere.
At the same time, power losses occurred on power distribution lines in central and southern Sweden. This is more than are normally required during a year of regular operations. Difficulty in using high-frequency radio communications to alert user to the problem. To understand the dynamical behavior of the coupled solar-terrestrial system and its potentially deleterious effects, it is imperative to understand first its gross time-averaged conditions and the extreme, long-time-base departures from the mean "space climate".
In the introduction to this Disciplinary Assessment, some aspects of the climatology of the four coupled regions Sun, interplanetary space, magnetosphere, ionosphere-upper atmosphere that comprise the solar-terrestrial system were outlined. Space climate models are especially important at present, given that our ability to provide accurate and specific space weather forecasts is rather limited at the present time. Indeed, knowledge of the space climate rather than space weather is used principally by engineers who design and build systems to withstand the equivalent of a hundred-year flood or storm.
This manufacturing philosophy may lead to inefficiency and costly overdesign. Ultimately, production of a reliable space weather forecast capability may give designers the confidence to build "smart" systems that take advantage of ad-. In the meantime, improving the validity of space climate models is an important first step toward the goal of understanding and mitigating the effects of the space environment.
The Sun is a variable star. Driven by dynamics in the solar interior, the solar magnetic field is continually evolving. The solar magnetic field causes the Sun's outer atmosphere, the solar corona, to be highly structured. Even when the Sun is relatively quiet, the solar wind near Earth is highly variable since the solar rotation with a period near 27 days produces a progression of different coronal regions facing the Earth.
Large deviations of the magnetic field from the standard Archimedean spiral direction are common. These temporal variations in solar wind are usually organized into alternating streams of high- and low-speed flows, with the density and field strength generally being strongest on the leading edges of the high-speed streams as a result of compression that occurs in interplanetary space. When the magnetic field within a compression region on the leading edge of a high-speed stream is directed southward, the solar wind is particularly effective in stimulating geomagnetic activity.
Flares are distinguished by enhanced electromagnetic radiation over a broad range of frequencies on time scales ranging from seconds to hours. Often particles are accelerated to high energies during the flare process. CMEs are events in which large amounts of solar material are suddenly injected into the solar wind. They originate in closed magnetic field regions in the solar corona that have not previously participated in the solar wind expansion.
Although they are distinct phenomena, flares and CMEs both seem to result from the release of stored energy from unstable magnetic configurations in the solar atmosphere. In particular, flares are usually observed on closed field lines statically bound in the solar atmosphere, whereas CMEs are characterized by mass motions on field lines being opened to interplanetary space.
CMEs exhibit a wide range of outward speeds. The faster CMEs usually produce major shock wave disturbances in the solar wind. The strong interplanetary magnetic fields produced by such disturbances are particularly effective in stimulating geomagnetic activity when they contain fields with southward components on their arrival at Earth.
Intense and long-lasting energetic particle events, usually called solar energetic particle SEP events, are often observed in interplanetary space in associa-. The temporal profiles of these particle enhancements differ from event to event, depending on the position of the Earth relative to the propagation direction of the interplanetary disturbances.
Typically, however, major energetic particle events in interplanetary space begin shortly after fast CMEs lift off from the Sun and continue until well after shocks driven by the CMEs pass the Earth several days later. Although some of the energetic particles observed in major SEP events often are accelerated near flare sites at the Sun, most of the energetic particles in major events appear to be the result of a shock acceleration process that occurs in the outer solar corona and in interplanetary space.
The various manifestations of solar variability in interplanetary space produce both magnetospheric and ionospheric responses, as illustrated in Figure II. The magnetospheric regions of particular relevance to space weather are shown in Figure II. Each of these regions is connected along geomagnetic field lines to low altitudes. For example, the ovals where auroral emission occurs are low-altitude projection s of the plasma sheet at high geomagnetic latitudes. Field lines in regions near the geomagnetic poles are interconnected to the interplanetary magnetic field and are said to be magnetically ''open.
When the interplanetary magnetic field at Earth contains a southward component, energy transfer from the solar wind to the magnetosphere increases and the magnetosphere becomes stressed. When the magnetosphere relaxes from this stressed state, strong plasma heating and particle acceleration occur in the near-Earth plasma sheet, enhanced particle precipitation into the upper atmosphere occurs at high latitudes with a concurrent brightening and motion of auroral forms, and electric current is diverted from the magnetotail down to the nightside ionosphere. This global release of energy is known as a magnetospheric substorm.
Because the magnetic field embedded in the solar wind often contains a south-ward-directed component even when the solar wind is not disturbed, magnetospheric substorms occur at a typical rate of one to a few per day. As noted above, particularly strong geomagnetic responses are triggered by the strong southward-directed fields often contained within compression regions on the leading edges of high-speed streams and by interplanetary shock disturbances driven by fast coronal mass ejections.
Geomagnetic activity stimulated in. The electric and magnetic field perturbations associated with large geomagnetic storms can extend to the Earth's surface, driving strong ground currents. New, transient radiation belts may also be formed in the largest such events. Because solar and interplanetary events vary in frequency and intensity with the solar activity cycle, so too does geomagnetic activity.
The most severe geomagnetic storms usually are associated with interplanetary disturbances driven by fast CMEs and thus are most common near the maximum of solar activity. Geomagnetic storms associated with high-speed stream compression regions are generally less severe, but tend to recur at the day rotation period of the Sun, particularly on the declining phase of the solar activity cycle.
Moreover, for unknown reasons, recurrent storms are much more effective in accelerating electrons to million-electron-volt energies in the outer reaches of the radiation belts. Hence, it is during the approach to solar activity minimum that the fluxes of these electrons with million-electron-volt energies are particularly. The ionosphere-upper atmosphere system also responds to changes in the external space environment at all local times and latitudes. The upper reaches of Earth's atmosphere lie at the low-altitude extension of the magnetosphere and include both neutral and charged constituents.
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The charged component is called the ionosphere and is collocated with the upper neutral atmosphere Figure II. The ionosphere responds to and affects both the magnetosphere and the neutral atmosphere and thus plays a crucial role in coupling the two. The physical properties of the ionosphere and upper neutral atmosphere are affected dynamically by changes in both solar radiation and magnetospheric electrodynamics. Solar ultraviolet radiation ionizes the neutral atmosphere, creating the ionospheric structure noted in Figure II.
The ionosphere extends from altitudes of about 90 to km, with local peaks in electron density near and km. Electrical currents, electric fields, and particle precipitation are all imposed onto the ionosphere from their magnetospheric source regions in the polar magnetic cusp and boundary layers, the geomagnetic tail, and the inner magnetosphere. Time variations in magnetospheric convection, especially during magnetospheric substorms and storms, couple electrodynamically with ionospheric motions via magnetically field-aligned currents in the auroral zone.
Horizontal ionospheric currents act to couple auroral latitudes to lower latitudes. During large geomagnetic disturbances, activity at relatively high magnetic latitudes can thus affect the nature of the near-equatorial ionosphere. These effects include enhanced or decreased ionization, enhanced or reduced winds, composition changes, heating, gravity wave generation, plasma irregularities and instabilities, and enhanced atmospheric density.
These may affect communications, electric power distribution, navigation, space system operations, satellite drag, geomagnetic surveys, and radiation dose. The ionosphere-upper atmosphere also responds to rapid changes in solar ionizing radiation and energetic particle precipitation that accompany transient solar events. These events, including solar flares and CMEs, produce significant changes in electron density at lower altitudes 80 to 90 km , which in turn inhibit or block high-frequency radio communication at all daytime latitudes.
From a practical standpoint, much of what is relevant to the human condition in space weather involves the Earth's ionosphere. This blanket of ionized matter, or plasma, around the Earth is more dense than that around any other planet, and one must approach the surface of the Sun to find a comparable plasma environment. In our ever-increasing dependence on communications involving satellites that lie far above the ionosphere, this medium must be traversed by electromagnetic waves, which carry our messages and even information about where we are located.
In addition to buffeting from above by the solar atmosphere, the ionosphere is subjected to enormous winds borne aloft by tidal and atmospheric gravity waves generated in the dense atmosphere of the Earth. Just as waves. To understand and assess the effects of the space environment on systems, it is necessary to know both the environment and the way in which technological systems interact with it. The following material provides several examples of the types of interactions that occur; the different classes of effects are outlined below.
Such a list is not exhaustive; indeed, it continues to grow as new and more sophisticated technologies are put to use in human endeavors. The principal space weather hazard to humans in space and at high altitudes is exposure to ionizing radiation. The exposure gained in high-altitude aircraft is lower in a spacecraft because of the shielding effect of the atmosphere above the aircraft.
The primary regions of concern for aircraft are the high magnetic latitudes, where energetic cosmic rays and solar particle events are not shielded by Earth's magnetic field. Manned space flight programs are also very concerned about the exposure of astronauts to radiation. For missions that leave low Earth orbit, the ability to traverse quickly known concentrations of radiation, such as the Earth's radiation belts, and to predict the occurrence of energetic solar particle events is of extreme importance.
Varying levels of solar UV during the solar cycle change the altitudinal profile of the ionosphere, thereby changing ground-to-ground transmission paths for radio communications that use the ionosphere as a reflection medium, and limit the maximum usable frequency MUF for such systems. In addition, magnetospheric storms create enhanced and localized ionization levels in the ionosphere, while the variations in the electric fields in the atmosphere-ionosphere electric circuit lead to instabilities that structure the ionospheric ionization.
This structured ionization can cause time-variable disruptions in ground-to-satellite and ground-to-ground transmission paths. High-frequency HF radio communications continue to be used by the Department of Defense, shortwave broadcasting authorities, mariners, and others. The ionosphere, which supports such communications, is subject to disturbances during which there can be degraded capability and even a total communications blackout. Sudden ionospheric disturbances caused by intense solar flares are short-lived minutes to an hour interruptions caused by increased absorption in the lowermost D- region of the Earth's ionosphere.
Longer-lived disruptions occur as a result of heating of the upper atmosphere at auroral latitudes. Composition changes carried by enhanced winds depress levels of ionospheric density in the F-layer at midlatitudes, resulting in poorer HF communications. This effect can last up to several days in severe magnetic storms.
For example, variations in the strength and location of ionospheric currents and the currents that couple the ionosphere and magnetosphere cause significant errors in navigation by magnetic compass systems. The variability of the ionospheric electron density, discussed above, causes phase shifts and time delays in global positioning system GPS signals, which can lead to ephemeris and position errors for the user and decreased reliability and accuracy of GPS products.
Electric power systems can be affected by currents induced in the Earth by enhanced ionospheric currents during magnetospheric storms and substorms. These effects are large enough to damage parts of power networks e. Space weather can similarly affect the function of modem telecommunication systems. For example, magnetospheric storms and substorms drive ionospheric currents that can in turn induce significant voltages in long transmission lines e.
To protect against this possibility, electrical design limits must be set very high with cost impacts on the systems. Satellites experience several different types of space environment effects. Similarly, polymerization and embrittlement of some materials by UV exposure or the single-event effects induced in electronics by galactic cosmic rays see Figure II.
Other satellite effects occur during transient space weather events. For example, satellite charging both surface and deep dielectric charging occurs when a satellite is rapidly immersed in a hot plasma or the energetic electron radiation is significantly enhanced above average levels for extended periods. If the charging level exceeds the dielectric strength of a component, an electrostatic discharge can occur and result in operational anomalies see Figure II.
Enhanced solar cell radiation damage can be caused by energetic solar particles. Accelerated decay of satellite orbits is caused by increased atmospheric density at satellite altitudes as a result of atmospheric heating via sporadic solar x-ray and UV input or dumping of magnetospheric energy into the ionosphere-atmosphere system see Figure II. Geomagnetic surveys from aircraft and on the Earth's surface are an important tool used by commercial companies in their searches for natural resources.
The variation in strength and position of the ionospheric and magnetosphere-ionosphere coupling currents can create significant errors in such surveys. For example, they can create strong signatures in the survey data that are related not to subsurface features but to transient ionospheric currents operating at the time of the survey.
These disturbances, which are called Appleton anomalies after their discoverer, were first photographed during the Apollo mission. Created by a fountain effect due to the geometry of the Earth's magnetic field, the anomaly zone often becomes extremely disturbed. Since most of the world's people live in this region, such severe space weather must be understood and predicted for commercial and military purposes.
The capabilities of our current space weather and climate prediction services are quite rudimentary compared to societal, commercial, and governmental needs. Because our basic understanding of fundamental physical processes is not well developed, integrated physical models do not currently exist at operational facilities, and many of the data required to drive these models are not available.
Thus, the space weather science plan must address some basic questions that must be answered before adequate space weather support can be delivered. As described above, major solar events have a profound effect on space weather in the vicinity of the Earth. In addition, there are effects driven by the quasi-stationary solar wind.
Because the disturbances evolve as they propagate. Can we predict the size of the coronal hole and the speed of the flow? In addition to understanding the causes and properties of space weather, a crucial element in progress toward quantitative and accurate space environment. The spatial and temporal evolution of the magnetospheric space environment is driven by and responds to variations in the solar wind and interplanetary magnetic field as described above.
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Consequently, the element that is crucial for progress toward quantitative space environment predictions of sufficient accuracy and specificity is a comprehensive physical understanding of the internal magnetospheric response to external variations. The dynamism of the magnetospheric space environment is governed by physical transfer mechanisms operative largely within the magnetospheric boundary layers, which separate interplanetary and magnetospheric regimes.
Presently, the major physical processes at these interfaces are fairly well known; however, a comprehensive and quantitative measure of the relative role of each transfer process is not well specified, as a function of either space or time. Magnetospheric space weather depends not only on the physics of the driver solar wind and of the mass, momentum, and energy filter boundary layer processes , but also on the complex internal magnetospheric response to the external, filtered stimuli.
These internal reconfigurations may be tightly coupled or may have a nonlinear response to the driver input. Regardless of the form of the response, most space weather effects are strongly connected with the most dynamic elements of geomagnetic storms and substorms. As such, there are specific scientific questions relevant to storms and substorms that require more complete answers than presently known. Each of these questions requires a quantification and sophistication beyond those presently available in order to improve space environment predictions.
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Questions include the following:. When discussing the electrodynamic response of the magnetosphere to external forces, it is imperative to recognize the importance of the coupled iono-. First, we need improved global models of the bulk macroscopic properties of the atmosphere and ionosphere. We must also make progress in understanding their dynamic responses to the space weather effects discussed above. Unlike the magnetospheric environment, the ionospheric-atmospheric environment is responsive to solar variations both directly e.
Both aspects are important and have several associated outstanding scientific questions, the former dependent primarily on photons and the latter on charged particles and fields. Predicting ionospheric space weather and its effects both in space and on the ground requires, in part, accurate descriptions of electric fields and currents present in the ionosphere at both auroral and subauroral latitudes.
As noted above, the magnetosphere and ionosphere are tightly coupled electrodynamically and must be treated as a system. The critical issues of the magnitude and location of time-dependent ionospheric currents and electric fields thereby rely on the physics operative both locally and globally.
At present, our understanding of the individual components is maturing; however, much work is needed to achieve the synthesis required to move to the next stage of physical understanding. Specific outstanding questions follow:. How are high-latitude, ionospheric variations transferred to low latitudes? Are the processes predictable? Do data exist to evaluate them? Are direct measurements or proxy data available to provide accurate answers? Another agent of ionospheric-atmospheric space weather effects, whose role is poorly quantified, is the very energetic charged particles that interact with.
Some ionospheric disturbances are thought to be initiated by the deposition of relativistic electrons and solar protons to low altitudes that enhance ionization and cause plasma instabilities. These instabilities lead to complicated ionospheric structure that can affect communications. Some of these energetic particles may even contribute to modifying mesospheric ozone indirectly through chemical and transport influences.
Over the past nearly 35 years of basic research, the solar-terrestrial and space physics communities have developed a broad empirical and theoretical understanding of solar-terrestrial relationships and the space environment through a balanced program of spaceflight experimentation, data analysis, and theory. This advance has been motivated largely by the intrinsic scientific merit of these studies.
In the past decade or so, increased emphasis has been placed on applying this basic knowledge to societal concerns about the space environment both in the private sector and in several national agencies [e. As a result, the first numerical models are now being developed to specify, nowcast, and forecast the space environment.
To see how the NSWP might evolve, it is instructive to compare first the field of space physics specifically, space weather with the development of atmospheric physics in particular, dynamic meteorology. Since their inception, numerical weather prediction models have shown a steady improvement in both their accuracy and their specificity of tropospheric weather over the last 35 years. One standard figure of merit is the so-called S1 score a measure of the hour prediction of the geopotential height at mbar , which when converted to a percentage accuracy has improved from approximately 28 percent predictive in to approximately 94 percent predictive in the early s.
This achievement was accomplished by a rigorous effort wherein each element supported and motivated the others: basic research, model development, model testing, application, data gathering, and assimilation. Throughout this effort, a strong customer base was established and continued to grow as forecast and specification capabilities improved. The interagency NSWP is now at the same crossroads that confronted the meteorology community in the early s. However, in at least one respect, speedier success might be anticipated because computational resources today are orders-of-magnitude more powerful and sophisticated than they were in the s.
In addition, a broad customer base that recognizes the importance of space weather to its operations or products has been established over the past 30 years. For significant improvement to be made in numerical space weather predictions, we must make progress on the same type of issues that confronted dynamic meteorologists 40 years ago.
It is important to implement existing space weather models quickly so that deficiencies can be identified rapidly and remedied. Concurrently, a vigorous research program should continue to explore the basic physics of the comprehensive space environment, and new advances should be included in improved operational numerical models through the NSWP. Another necessary element for progress is the identification of critical input parameters and data needed for models and the development of experimental programs to provide these data.
To summarize, the following efforts must be implemented that are supportive of a well-balanced space weather initiative many of which are already ongoing :. A space weather program should achieve the following: 1 increase humankind's understanding of space weather processes and problems to a level high enough to implement numerical space weather prediction codes; 2 continually improve the capability to specify, nowcast, and forecast key aspects of the space environment; and 3 through a combination of items 1 and 2, mitigate the negative effects of space weather on human life and technology.
To achieve these goals, progress must be made in five areas:. Develop and disseminate a better basic understanding of the relevant physical phenomena and processes. Generate statistical models, based on comprehensive measurements, that specify the average space environment properties and the range of anticipated values space climate.
Produce nowcasting capabilities that permit the instantaneous state of the magnetosphere to be described on the basis of specific near-real-time observations. Build numerical forecasting capabilities that provide accurate predictions of space weather properties with enough advance warning to allow mitigating actions. Evaluate mitigation strategies based on a synthesis of scientific understanding, engineering considerations, and operational guidelines. A number of existing and planned satellite programs can contribute to this initiative e.
The scientists published their findings in the leading international journal Nature Communications. Most of the matter we encounter in our everyday lives comes in the form of solid, liquid or gas, but the majority of the Universe is composed of plasma -- a highly unstable and electrically charged fluid. The Sun is also made up of this plasma. Despite being the most common form of matter in the Universe plasma remains a mystery, mainly due to its scarcity in natural conditions on Earth, which makes it difficult to study.
Special laboratories on Earth recreate the extreme conditions of space for this purpose, but the Sun represents an all-natural laboratory to study how plasma behaves in conditions that are often too extreme for the manually constructed Earth-based laboratories. He said: "The solar atmosphere is a hotbed of extreme activity, with plasma temperatures in excess of 1 million degrees Celsius and particles that travel close to light-speed. The light-speed particles shine bright at radio wavelengths, so we're able to monitor exactly how plasmas behave with large radio telescopes.
We combined the radio observations with ultraviolet cameras on NASA's space-based Solar Dynamics Observatory spacecraft to show that plasma on the sun can often emit radio light that pulses like a light-house. We have known about this activity for decades, but our use of space and ground-based equipment allowed us to image the radio pulses for the first time and see exactly how plasmas become unstable in the solar atmosphere.
Studying the behaviour of plasmas on the Sun allows for a comparison of how they behave on Earth, where much effort is now under way to build magnetic confinement fusion reactors. These are nuclear energy generators that are much safer, cleaner and more efficient than their fission reactor cousins that we currently use for energy today.
Professor at DIAS and collaborator on the project, Peter Gallagher, said: "Nuclear fusion is a different type of nuclear energy generation that fuses plasma atoms together, as opposed to breaking them apart like fission does. Fusion is more stable and safer, and it doesn't require highly radioactive fuel; in fact, much of the waste material from fusion is inert helium.
As soon as the plasma starts generating energy, some natural process switches off the reaction. While this switch-off behaviour is like an inherent safety switch -- fusion reactors cannot form runaway reactions -- it also means the plasma is difficult to maintain in a stable state for energy generation.
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