Extreme space weather events
Alain Hilgers Space Environments and Effects section European Space Agency
17 March 2016, DGAC, Paris, F.
ESA UNCLASSIFIED – For Official Use Content
• Definitions
• Examples
• Challenges
ESA UNCLASSIFIED – For Official Use Definition: Space weather
• Change in the space environment with potential effects on human activity or technology.
ESA UNCLASSIFIED – For Official Use Space weather effect
ESA UNCLASSIFIED – For Official Use Definition: Space weather event
• Change for which the amplitude of a descriptive parameter goes beyond a given threshold.
• Example: Geomagnetic storm (Dst index – Disturbance storm time)
ESA UNCLASSIFIED – For Official Use Space weather event: solar flare
•Example: Solar flare
SOHO/EIT
ESA UNCLASSIFIED – For Official Use Definition: Extreme event
• Extreme space weather: Space weather event with an amplitude at the extreme of an historical distribution.
Example: x-ray flare distribution over 1991-2000
Ridley, 2012.
ESA UNCLASSIFIED – For Official Use Examples of extreme events
• 1645-1715 (Maunder minimum): sunspot number remained exceptionally low.
• Sept 1859 (Carrington event): Auroras observed all over the globe. Dst done to about -900 nT.
• May 1921: Auroras observed down to very low latitude. Several urban fires due to telegraph or electrical cables. Dst down to about -820 to -900 nT.
• Feb 1956: Strong geomagnetic storm. Radio blackout. Intense ground level enhancement of neutrons.
• March 1989: Aurora down to low latitudes. Dst down to -589. Hydro- Quebec power network collapsed. 6 millions people affected.
• July 2012: Extremely high speed CME passed spacecraft but missed Earth.
ESA UNCLASSIFIED – For Official Use Carrington event
Magnetic measurement at Greenwich observatory [Cliver and Dietrich, 2012]
ESA UNCLASSIFIED – For Official Use Challenges
• Key questions • How to cope with extreme events • How large are they? • How often do they occur?
• Technological • Scientific • Economical
ESA UNCLASSIFIED – For Official Use Technological challenge
• 3 approaches to cope with space environment
• Avoid: choice of right place to install the system.
• Shield: protect the system against reasonable worst case.
• Adapt: operate as a function of environmental conditions.
• All 3 approaches require knowledge of the space environment conditions
ESA UNCLASSIFIED – For Official Use Scientific challenges
• Objective: develop accurate models to predict the event.
• Issues: • Need to gather enough data for inference and verification • Events are rare so there is little data • Extreme events may have gone off-scale or measurements capabilities and methods may not be appropriate. • Statistics are affected by lack of continuity in measurement and recording methods • Proxies are always questionable
ESA UNCLASSIFIED – For Official Use Understanding geomagnetic storms
ESA UNCLASSIFIED – For Official Use Predicting July 2012 storm event if it had reached Earth…
ESA UNCLASSIFIED – For Official Use Other extremes predictions…
• Maximum geomagnetic storm • Seems to be of the order Carrington event storm (or twice) with probability of ~1 per 100 Y.
Ridley, 2012. • Maximum flare intensity • Seems to be 100 to 300 times what has been observed so far (based on solar analogs).
• Maximum solar storm particle flux • Seems to be of the order of 1972 solar particle event (based on Earth ice and moon samples). Schrijver, 2015.
ESA UNCLASSIFIED – For Official Use Economical challenge
• Optimisation of Cost/Benefit
• Issues: • Cost of measures • Over shielding • False alarms • Extreme events->extreme costs • Replacement of 1 transformer= a few millions +2 to 3 months outage. • 1 billion USD for hydro Quebec event • Estimate now for a future major storm may be 100 times this. • Threat for civilisation (1 of the 5 major world shock risk identified by OECD).
ESA UNCLASSIFIED – For Official Use Conclusion
• Modern society is susceptible to space weather • Extreme events are potentially a threat • There are still very high uncertainties • Methods and techniques to increase knowledge and preparedness are required • Scientific research • Routine observations • Awareness
ESA UNCLASSIFIED – For Official Use BACKUP SLIDES
ESA UNCLASSIFIED – For Official Use NOAA scale – Geomagnetic storms
ESA UNCLASSIFIED – For Official Use NOAA scale – Solar storms
ESA UNCLASSIFIED – For Official Use NOAA scale – Radio blackouts
ESA UNCLASSIFIED – For Official Use