Space Weather describes a series of changing conditions in the natural space environment of our solar system. Space weather phenomena are triggered by events occurring on the Sun and in interplanetary space, which eventually impact the natural Earth environment. Although not posing direct risk to human life on Earth, space weather affects a number of today’s critical technologies, therefore, the global economy. The adverse effects on energy infrastructure, transport, radio communication, observation, navigation and communication satellites, etc., result in reduced reliability of critical systems with potential effects on human safety.
Space weather monitoring and prediction services are already regularly used by commercial airlines, the satellite industry, drilling and surveying operations, power grid operators, pipeline designers, and users of satellite-based navigation systems. Emergency management agencies are developing procedures to manage the risks of severe space weather events as part of their overall risk management approach. Since November 2019, three (soon to be four) Global Space Weather Centres have been providing space weather services to International Civil Aviation Organization (ICAO).
WMO recognizes that there is an increasing demand for space weather services as society is becoming ever more dependent on technologies adversely impacted by space weather events. Procedures are being developed by a number of countries to manage the risks of severe space weather events as part of multi-hazard disaster risk reduction approaches. It is anticipated that the demand for space weather information will expand with broader awareness of the impacts of space weather events, the increasing exposure of society, and the evolution of space weather products and services.
The Four-Year Plan for WMO Coordination of Space Weather Activities 2020-2023 (FYP2020-2023) was approved by the Eighteenth World Meteorological Congress (Cg-18) in 2019. The implementation of the FYP2020-2023 will provide significant benefits to WMO Members in terms of more precise observations and improved services.
WMO has also incorporated space weather observations into the new WMO Unified Data Policy. The new Policy will provide the foundation for identifying core observations required for Space Weather Services, which will be detailed in the WMO Technical Regulations.
This article introduces this relatively new area of work at WMO, specifically the related societal impacts, and observations and data requirements. It further expands on space weather services and international collaboration.
Space weather: A new hazard of the technological era
Space weather, for the most part, cannot be observed or felt directly by humans, except for the occasional spectacular displays of the aurora borealis (Figure 1) or australis, caused by disturbances of the natural electromagnetic fields and ionized particles in the upper layer of atmosphere (ionosphere). In contrast, many technologies interact with the Earth’s natural electromagnetic environment, so regularly experience the detrimental effects of space weather.
Figure 1 – Aurora borealis (Lionel Peyraud/WMO)
These effects have been observed for a long time. The accuracy of pointing needles in compasses (invented over 2000 years ago and used for navigation/orientation since then) is hindered by space weather. The telegraph, an eighteenth-century invention, made the effects of space weather on technology broadly apparent. Telegraph wires are essentially long linear conductors at the surface of the Earth, as such they are sensitive to the natural variations of the Earth electromagnetic field. By coincide, the telegraph developed on a global scale during a period of high solar activity. Severe geomagnetic storms from 28 August to 2 September 1859 (known as the “Carrington event”, the largest space weather episode in modern history) caused widespread disruption of the telegraphic systems in Europe and North America.
As presented in historical book by Prescott (1866), Mr. O. S. Wood, Superintendent of the Canadian telegraph lines, reported: "I never, in my experience of fifteen years … witnessed anything like the extraordinary effect of the aurora borealis … last night. The line was in most perfect order, and well-skilled operators worked incessantly from eight o'clock last evening till one o'clock this morning …; but at the latter hour, so completely were the wires under the influence of the aurora borealis, that it was found utterly impossible to communicate between the telegraph stations, and the line was closed for the night."
Wireless communication started in the early twentieth century with invention of radio. However, the absence of the long conductors did not eliminate the space weather impacts. Radio communication is subject to the interaction of the radio waves with the ionosphere, electrically conductive layer of the atmosphere, which become severely disturbed during space weather events, causing interference with the radio signal propagation. According to L. Lanzerotti (2001), Marconi in 1928 commented on this phenomenon as "...times of bad fading [of radio signals] practically always coincide with the appearance of large sun-spots and intense aurora-borealis usually accompanied by magnetic storms...”
High frequency (HF) radio communication in the Arctic/Antarctic areas is affected more strongly than in other locations because of the higher intensity of the disturbances close to the magnetic poles.
Space weather effects were observed on power grids, according to Davidson, as early as in 1940. The most severe case was recorded in 1989, when the Hydro-Québec power system collapsed due to a geomagnetic storm on 13/14 March, 1989. The event unfolded over just a few minutes, but left hundreds of thousands of people and businesses without power for nine hours.
One of the strongest space weather events occurred in October 2003. It had widespread effects on vulnerable infrastructure and significantly influenced public attitudes on space weather. Excerpts from the report published by U.S. National Research Council in 2008:
“On October 30, 2003, the House Committee on Science, Subcommittee on Environment, Technology, and Standards held a hearing on space weather and on the roles and responsibilities of the various agencies involved in the collection, dissemination, and use of space weather data. (…) Questions included, What is the proper level of funding for agencies involved in space environmental predictions? and, What is the importance of such predictions to industry and commerce? Coincidentally, and rather remarkably, at that very time the Sun exhibited some of its strongest eruptive activity in the last three decades. Enormous outbursts of energy from the Sun during late October and early November 2003 produced intense solar energetic particle events and triggered severe geomagnetic storms…Due to the variety and intensity of this solar activity outbreak, most industries vulnerable to space weather experienced some degree of impact to their operations... These events reminded scientists and policy makers alike how significantly the space environment can affect human society and its various space- and ground-based technologies.”
Presented in the same report are some estimations of the socio-economic impacts of October 2003 space weather event on vulnerable technology: “The Sydkraft utility group in Sweden reported that strong geomagnetically induced currents (GIC) over Northern Europe caused transformer problems and even a system failure and subsequent blackout. Radiation storm levels were high enough to prompt NASA [National Aeronautics and Space Administration] officials to issue a flight directive to the ISS [International Space Station] astronauts to take precautionary shelter. Airlines took unprecedented actions in their high latitude routes to avoid the high radiation levels and communication blackout areas. Rerouted flights cost airlines US$ 10,000 to US$ 100,000 per flight. Numerous anomalies were reported by deep space missions and by satellites at all orbits. GSFC [Goddard Space Flight Centre] Space Science Mission Operations Team indicated that approximately 59% of the Earth and Space science missions were impacted. The storms are suspected to have caused the loss of the US$ 640 million ADEOS-2 [Advanced Earth Observing Satellite spacecraft. On board the ADEOS-2 was the [US]$ 150 million NASA SeaWinds instrument."
Today, thousands of satellites in near-Earth space are enabling weather forecasts, communication, navigation, TV broadcast and lots more. Hazardous space weather conditions directly impact the satellite systems and interfere with the services they provide. One of the most widely used satellite-based services is provided by the Global Navigation Satellite System (GNSS), with applications ranging from navigation to timing, and with users from a broad range of economic sectors from aviation to banking. This service is also vulnerable to severe space weather. For example, the events of October 2003 had a major impact on the services of GPS-based [Global Positioning System] Wide Area Augmentation System (WAAS) for about 30 hours.
It should be noted that the Carrington event of 1859 was several times larger than any event experienced over the past 50 years. A similar event today would lead to much deeper and more widespread socioeconomic disruptions than any of examples presented above. The growing global vulnerability to space weather is an issue of an increasing concern. Many studies have been undertaken from 2008 to 2021 (see -) to evaluate the economic and societal impacts of severe space weather events and the required level of services.
Sources of space weather events and essential space weather observations
In order to provide essential services, the space weather needs to be observed all the way from the Sun to the Earth with high accuracy, and the data need to be exchanged in a timely manner. This is a challenging task, given the spatial extent of the space weather domain and the limited observing capabilities to cover the space between the Sun and the Earth as well as Earth surface itself. The wide variety of physical processes governing space weather requires development of new instrument capabilities. Numerically complex models of the propagation of space weather disturbances play an essential role in the provision of the forecasts for such events.
Space weather observations rely on ground-based and space-borne operational and research instruments, which monitor the conditions of (starting from the most distant) the Sun, solar wind and heliosphere, magnetosphere, ionosphere, thermosphere and the ground geomagnetic field.
There are multiple types of solar disturbances, which result in different phenomena in the near-Earth space and on the ground and different impacts on technologies (Figure 2). Two solar phenomena are the sources of the most immediate space weather effects: solar flares, with their impacts seen on the Earth in minutes, and solar energetic particles (or SEP), reaching the Earth in hours. Both of these fast-moving phenomena interfere with satellite operations and disturb the ionosphere, affecting the radio communication and GNSS signals. In addition, they can both increase radiation at the near-Earth space and even at high altitudes.
Slower than the first two, Coronal Mass Ejections (CME) are emissions of plasma that reach the Earth within one to several days after the event onset on the Sun. They are responsible for the most powerful geomagnetic and ionospheric storms, impacting multiple systems operating in space and on the ground such as satellites in various orbits, communication, navigation and power grids.
Figure 2 – Space weather phenomena and affected assets in space and on Earth (©ESA/Science Office, CC BY-SA 3.0 IGO)
In addition, there are regularly recurring phenomena corresponding to the solar rotation (~ 27 days) that have lower-magnitude impacts on technology. Longer periodicity of the solar activity is often characterized by a sunspot number (and solar radio flux at 10.7 cm wavelength). They recur approximately every 11 years and have served as a solar “climatology” index for many centuries. The earliest records of observations of the Sun (sunspots) by naked eye date back to roughly 200 BC.
Some solar observations are provided by ground-based observatories – both optical and radio frequency. These observations are essential for many space weather applications, including monitoring long-term and short-term solar activity, and as input data for numerical prediction models of space weather (Figure 3). There are currently more than 80 ground-based solar observatories in operation as per the International Astronomical Union.
Figure 3 - Radio observatory in Penticton, Canada (left) and its long-term observation of solar radio signal at 10.7 cm wavelength (right), showing the 11-year solar cycles (from Tapping, K. 2013)
Space-based solar observations add essential measurements of the Sun, without obstruction from the Earth’s atmosphere, and allow in situ monitoring of the propagation of disturbances of solar wind plasma and solar energetic particles (Figure 4).
Figure 4 - SOlar and Heliospheric Observatory (SOHO) satellite observations of the 14 July 2000 space weather event in different wavelengths. Left: flash of the solar flare at 10:24 UT; Middle: full halo Coronal Mass Ejection at 10:54 UT (the brightest central part of the Sun is covered); Right: “snow” due to the subsequent Solar Energetic Particles impact on the satellite imager at 11:30 UT. (Courtesy NASA/ESA)
Space missions provide in situ observations of the critical parameters of solar disturbances, such as magnetic field and characteristics of charged particles, before they hit the Earth (Figure 5). However, surface-based measurements are equally important as they provide critical situational awareness and, in many cases, serve as essential inputs in forecast models.
|Figure 5 - Left: components of ACE satellite with the numerous particle detectors in the centre and magnetometers attached to the solar panels (courtesy of NASA); Right: artist illustration of satellites observing space weather at different orbits from|
Figure 6. Left: Magnetometer (from Hrvoic and Newitt); Right: Photo of the Geomagnetic observatory at Iqaluit, Canada (courtesy of Mark Lamothe)
Ground geomagnetic variations, which affect ground infrastructure, are monitored by the geomagnetic observatories (Figure 6). There are more than 100 such observatories in the Intermagnet consortium and more beyond the Intermagnet, operated, for example, by universities. Ground enhancements of neutrons due to highly energetic particles interaction with the atmosphere are observed by neutron monitors (~35 stations) and are used in radiation models at different altitudes.
Ionospheric “weather” is monitored from the ground using both active and passive methods by some 80 ionosondes, about 40 riometers and numerous GNSS receivers around the globe (approximately 500). Ionospheric “hybrid” measurements are provided by ground receivers of GNSS satellite signals (Figure 7).
Figure 7 - Left: Map of Total Electron Content of the ionosphere over Canada obtained using GNSS data. Right: Map of GNSS tracking stations
It should be emphasized that the lack of sufficient in situ (i.e. space-based) monitoring of the initiation and propagation of the solar disturbances is a problem that will not to be fully resolved in the near future. However, progress can be made through a coordinated approach to the identification of the observational gaps and prioritization of coordinated space missions.
Similarly, ground-based observational networks, operated by diverse entities from governments to university research groups, provide limited geographical coverage. They have different priorities and capabilities, and their efforts are not currently coordinated within a unified space weather system for timely provision of robust operational quality data. In order to successfully mitigate the detrimental impacts of space weather, efforts should be made to provide the sufficient observational capabilities on Earth and in space, together with the numerical modelling capabilities of both the phenomena and their technological impacts. The scope of these efforts is beyond the capabilities of any individual country. The issue is, therefore, being addressed through coordinated efforts guided by WMO (Figure 8).
|Figure 8. Requirements defined for space weather observations presented as part of WMO OSCAR Tool|
In the same manner as for Earth system observations, such as weather, climate and atmospheric composition, space- and surface-based space weather observing systems would be best coordinated using principles of the WMO Integrated Global Observing System (WIGOS). Consistent, quality-assured space weather products should be made freely and openly available to Members and wider audience through WMO Information System (WIS) in accordance to WMO standards.
Space Weather services and WMO: consistent progress towards Space Weather Watch
The first prediction of a space weather phenomenon (i.e. an aurora) was performed in the mid-1700s, as presented in Cade. The first predictions of the impact of space weather on technology, according to presentation of G. Major in 2016, was associated with the telegraph. It was published in 1879 (when the sunspot number started to rise) in the Journal of the Society of Telegraphic Engineers and Electricians, in order to warn the telegraph community of a possible increase in geomagnetic activity and associated problems with telegraph operations.
The start of the regular prediction of space weather conditions was initiated by the Union Radio Scientifique International (URSI). It recognized that changes in the space environment would affect radio signals and suggested that a daily service of radio-cosmic bulletins (URSIgrams) should be broadcast. The first broadcast of the radio propagation conditions was in 1928 from the Eiffel Tower.
Currently, space weather services are provided by 20 Space Weather Centres operated in different countries. Since 1962, the International Space Environment Service (ISES) has served as the primary “umbrella” organization for space weather services, acting as a forum to share data, to exchange and compare forecasts, to discuss user needs and to identify the highest priorities for improving services.
Given the planetary scale of space weather events, global coordination is essential and will play a key role in improving the resilience of countries to space weather effects. WMO is one of the few organizations that fosters operational global collaboration. As such, the Organization has the capabilities to arrange for the relevant space weather information to be available to all WMO Members as part of capacity building.
In 2008, the WMO Executive Council (EC-LX) noted the considerable impacts of space weather on critical infrastructure and important human activities and acknowledged the potential synergy between meteorological and space weather services to operational users. The Sixteenth World Meteorological Congress (Cg-16) acknowledged the need for a coordinated effort by WMO Members to protect the society against the global hazards of space weather. In May 2010, WMO established the Inter-programme Coordination Team on Space Weather (ICTSW), which, in turn, developed the first Four-year Plan for WMO Coordination of Space Weather Activities (FYP 2016-2019).
In May 2015, the World Meteorological Congress (Cg-17) agreed that WMO should undertake international coordination of operational space weather monitoring and forecasting in order to support the protection of life, property and critical infrastructure and to mitigate the impacts on economic activities. In 2016, the 68th session of the Executive Council (EC-68) approved FYP2016-2019 and the establishment of an Inter-Programme Team on Space Weather Information, Systems and Services. An updated FYP2020-2023 was approved by Cg-18 in 2019.
With the emerging need for improved space weather services and hence for space weather relevant observations WMO is also addressing the need for space weather observations in the new WMO Unified Data Policy. The new Policy will provide the foundation for identifying core observations required for space weather services and will be detailed in the WMO Technical Regulations.
Currently, work is ongoing to integrate space weather within core WMO activities, with the aim to develop a global Space Weather Watch. For that, the space-based and ground-based space weather observing systems should be coordinated using principles of WIGOS and consistent, quality-assured space weather products available to Members through WIS.
 Prescott, G.B., History Theory and Practice of the Electric Telegraph, Ticknor and Fields, Boston, 1866
 Lanzerotti L.J. (2001) Space Weather Effects on Communications. In: Daglis I. (eds) Space Storms and Space Weather Hazards. NATO Science Series, vol 38. https://doi.org/10.1007/978-94-010-0983-6_12
 Davidson, W. 1940. “The Magnetic Storm of March 24, 1940 – Effects in the Power System.” Edison Electric Institute Bulletin 8: 365–366
 Guillon et al., 2016. A colorful blackout: The havoc caused by auroral electrojet generated magnetic field variations in 1989. IEEE Power and Energy Magazine, 14(6), 59-61
 Severe Space Weather Events: Understanding Societal and Economic Impacts: A Workshop Report. Washington, DC: The National Academies Press, 2008.
 Kevin D. Pang and Kevin K. Yau, Eos, Vol. 83, No. 43,22 October 2002
 Tapping, K. F. (2013), The 10.7 cm solar radio ﬂux (F10.7), Space Weather, 11, 394–406,doi:10.1002/swe.20064
 Hrvoic I., Newitt L.R. (2011) Instruments and Methodologies for Measurement of the Earth’s Magnetic Field. In: Mandea M., Korte M. (eds) Geomagnetic Observations and Models. IAGA Special Sopron Book Series, vol 5. Springer, Dordrecht. https://doi.org/10.1007/978-90-481-9858-0_5
 G. Major, The Early History of Space Weather: Observations that Connected Solar Activity and its Influence on the Earth, https://ams.confex.com/ams/96Annual/webprogram/Session39849.html
Larisa Trichtchenko, Canadian Space Weather Forecast Centre, Natural Resources Canada, and Kenneth Holmlund, WMO Secretariat