Space weather

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Space weather is the concept of changing environmental conditions in outer space. It is distinct from the concept of weather within an atmosphere, and generally deals with the interactions of ambient radiation and matter within interplanetary, and occasionally interstellar space. From the definition of the National Academy of Science: "Space weather describes the conditions in space that affect Earth and its technological systems. Our space weather is a consequence of the behavior of the sun, the nature of Earth's magnetic field, and our location in the solar system." ^[1]

Within our own solar system, space weather is greatly influenced by the speed and density of the solar wind and the interplanetary magnetic field (IMF) carried by the solar wind plasma. A variety of physical phenomena are associated with space weather, including geomagnetic storms and substorms, energization of the Van Allen radiation belts, ionospheric disturbances and scintillation, aurora and geomagnetically induced currents at Earth's surface. Coronal Mass Ejections and their associated shock waves are also important drivers of space weather as they can compress the magnetosphere and trigger geomagnetic storms. Solar Energetic Particles, acclerated by Coronal Mass Ejections or solar flares are also an important driver of space weather as they can damage electronics onboard spacecraft and threaten the life of astronauts.

Space weather exerts a profound influence in several areas related to space exploration and development. Changing geomagnetic conditions can induce changes in atmospheric density causing the rapid degradation of spacecraft altitude in Low Earth orbit. Geomagnetic storms due to increased solar activity can potentially blind sensors aboard spacecraft, or interfere with on-board electronics. An understanding of space environmental conditions is also important in designing shielding and life support systems for manned spacecraft. There is also some concern that geomagnetic storms may also expose conventional aircraft flying at high latitudes to increased amounts of radiation.

Contents 1 Modeling Efforts 2 Examples of space weather events 3 Space weather at the Earth’s surface 3.1 Geophysical Exploration 3.2 Geophysics and Hydrocarbon Production 3.3 Further Reading 3.4 Links 4 See also 5 Notes 6 Bibliography 7 External links

[edit] Modeling Efforts

Major modelling efforts to simulate the space environment from the Sun to the Earth and beyond using three-dimensional global Magnetohydrodynamics frameworks have been undertaken since the 1990s. In the United States, the two major centers are the Center for Space Environment Modeling (CSEM) and the Center for Integrated Space weather Modeling (CISM).

[edit] Examples of space weather events

• The best-known example of space weather events is the collapse of the HydroQuebec power network on March 13, 1989 due to geomagnetically induced currents. This was started by a transformer failure, which led to a general blackout, which lasted more than 9 hours and affected 6 million people. The geomagnetic storm causing this event was itself the result of a Coronal Mass Ejection, ejected from the Sun on March 9, 1989.^[2]
  
• A Coronal Mass Ejection on January 7, 1997 hit the Earth's magnetosphere on January 10 and caused the loss of the AT&T Telstar 401 communication satellite (a $200 million value).^[3]
  
• Transpolar routes flown by airplanes are particularly sensible to space weather, in part because of Federal Aviation Regulations requiring reliable communication over the entire flight. It is estimated to cost about $100,000 each time such a flight is diverted from a polar route. Nine airlines are currently operating polar routes. ^[4]
  
• No large Solar Energetic Particles event happened during a manned mission. However, such a large event happened on August 7, 1972, between Apollo 16 and Apollo 17. The dose of particles which would have hit an astronaut, had this event happened during one of these missions, would have been deadly or at least life-threatening.^[5] Nozomi Mars Probe was hit by a large Solar Energetic Particles event on April 21, 2002, which caused large-scale failure. The mission, which was already about 3 years behind schedule, was eventually abandoned in December 2003.^[6]

[edit] Space weather at the Earth’s surface

The best known ground-level consequence of space weather is geomagnetically induced currents, or GIC. These are damaging electrical currents that can flow in power grids, pipelines and other conducting networks. GIC are described in detail elsewhere. Rapid magnetic changes on the ground - that occur during geomagnetic storms and are associated with space weather - can also be important for activities such as geophysical mapping and hydrocarbon production. Space weather impacts on these activities are described here.

[edit] Geophysical Exploration

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

[edit] Geophysics and Hydrocarbon Production

For economic and other reasons, oil and gas production often involves the directional drilling of well paths many kilometres from a single wellhead in both the horizontal and vertical directions. The accuracy requirements are strict, due to target size – reservoirs may only be a few tens to hundreds of metres across – and for safety reasons, because of the proximity of other boreholes. Surveying by the most accurate gyroscopic method is expensive, since it can involve the cessation of drilling for a number of 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 the drilling direction and nearby magnetic observatories prove vital (Clark and Clarke, 2001; Reay et al, 2006). Magnetic data and storm forecasts can also be helpful in clarifying unknown sources of drilling error on an on-going basis.

[edit] Further Reading

• 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.
• 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.

[edit] Links

• British Geological Survey's Geomagnetism Applications and Services site
• Finnish Meteorological Institute's ground effects site
• Australian Space Weather Agency's site about effects on aeromagnetic surveys

[edit] See also

• Atmospheric physics
• Plasma physics
• Space exploration
• Sudden ionospheric disturbance
• Coronal Mass Ejection
• Geomagnetic storm

[edit] Notes

1. ^ Space Weather: A Research Perspective National Academy of Science, 1997
2. ^ Geomagnetic Storms Can Threaten Electric Power Grid Earth in Space, Vol. 9, No. 7, March 1997, pp.9-11 (American Geophysical Union)
3. ^ Space Weather and Satellite loss
4. ^ United polar flights Mike Stills
5. ^ 1972 Apollo Mission and SEP events (NASA)
6. ^ Nozomi Mars Probe hit by a large SEP event

[edit] Bibliography

• Rainer Schwenn, Space Weather, Living Reviews in Solar Physics 3, (2006), 2, online article.

[edit] External links

• NOAA-SEC Space Weather Now - (U.S. National Oceanic and Atmospheric Administration [NOAA])
• NSWP Strategic Plan - (NOAA)
• NSWP Implementation Plan - (NOAA)
• USGS Geomagnetism Program - (United States Geological Survey)
• Lund Space Weather Center - (Swedish Institute of Space Physics)
• Spaceweather.com - Space Weather news, forecasts and pictures
• Storms from the Sun - popular science writing about the Sun and space weather effects
• Space Weather and Radio Propagation Live and historical data and images with a perspective on how it affects radio propagation.
• Space Weather forums at HFradio.org
• Solar Terrestrial Dispatch
• Active Region Monitor Live and archived solar region images and data.
• The Australian Space Weather Agency
• Latest Solar Events (Large bandwidth)
• Space Weather Canada
• Official Keepers of the Sunspot Record Royal Observatory of Belgium / SIDC.
• Official SOHO Web site Solar and Heliospheric Observatory] Solar and space weather images and data.
• Solar Region Maps
• Large Angle and Spectrometric Coronagraph Experiment (LASCO) LASCO solar images and information.

The following external link is designed for use by cell phones and mobile devices that can display content using Wireless Markup Language and the Wireless Application Protocol:

• WAP/WML Space Weather Resources View live Space weather data and images, and more.