In March 1989, six million people in the Canadian province of Quebec suffered a nine-hour blackout due to currents induced in their electricity grid by a geomagnetic storm. The currents themselves were caused by charged particles from a solar coronal mass ejection which struck Earth. There are reports of a storm 150 years ago with many times that power.
Today, such events would be even more disastrous, knocking out the electronic and communications systems upon which we all depend.
That’s why the US, Australia and many other developed nations are investing in understanding and modelling the Sun-Earth system to enable us to forecast space weather, according to Colorado researcher Tim Fuller Rowell.
Space Weather and its Impact on Technology and Society
CIRES Center for Space Weather
University of Colorado and NOAA’s Space Weather Prediction Center Boulder, Colorado, USA
Space Weather affects many of our technological systems, and can be driven by the Sun or through connections with terrestrial weather.Modern society and technology have yet to experience the full force of the Sun.
I. INTRODUCTIONSpace Weather refers to the conditions in space surroundingus that effect technological systems and society . When ourSun is active it can blast Earth with intense X-rays andbombard us with plasma and energetic particles. Manytechnological systems can be impacted, some of which affectus directly. For instance, currents can be induced in power linesand transformers resulting in disruption of power; satelliteelectronics and control systems can be impacted resulting in thetotal loss of a satellite; astronauts and airline passengers onpolar routes are exposed to increased radiation hazard; theionosphere can also be enhanced and significantly morestructured affecting both communication, global navigationsystems, and cancellation of all polar airline routes; and theatmosphere can expand causing degradation of satellite orbits,loss of tracking, and increased risk of collisions.
Modern society and technology has yet to experience thefull force of the Sun. There is compelling evidence that just 150years ago Earth was hit by a Solar event many times the powerof anything experienced in the current era. As our societybecome increasingly reliant on technology and the complexmatrix of interdependencies among critical infrastructurebecomes more prevalent, it has been estimated that a similarevent would cost more than $1 trillion, and take years torecover from . Forecasting such an event may mitigate someof the damage, but certainly not all.
The first impact of a solar storm is seen within 8 minutes, asthe solar X-rays ionize the atmosphere, absorb communicationsignals, and prevent high frequency communication. Energeticparticles arrive at Earth within the hour damaging spacecraftelectronics and causing radiation hazard. The solar windplasma follows within a day or two, which heats the upperatmosphere, drives winds to speeds of 2000 mph, and increasesionospheric plasma densities.
Space weather has its impact even if a massive solar stormis not approaching. Just as meteorological weather forecasts arevaluable even if there is not a hurricane or typhoonapproaching, so to are space weather forecasts. Although not asdevastating as a massive solar storm, day-to-day changes in theionosphere can still disrupt communications and navigation.The equatorial and low latitude ionosphere are part of theglobal system affected by both intense solar events and day-todaychanges. Although some of the day-to-day modulation ofthe ionosphere at low latitude is still driven by the modestfluctuation in the Sun and solar wind, we now know that atleast half of this ionospheric variability arises from connectionsto terrestrial weather. Significant atmospheric events, such assudden stratospheric warmings, can propagate upward andcause a 50% increase in plasma density and change thelikelihood of ionospheric irregularities, affectingcommunication signals and navigation accuracy.
Efforts are underway to understand and model the Sun-Earth system to enable space weather forecasts to be reliableand timely. Solar and solar wind forecasting is still a majorchallenge. However, since data assimilation has enabledmeteorological weather to be forecast with reasonable accuracyseveral days ahead, the possibility of at least forecasting thiscomponent of space weather is now a real possibility.
. SWPC Forecasts; http://www.swpc.noaa.gov/. Severe Space Weather Events, Workshop Report.Committee on the societal and economic impacts of severespace weather events, Chair Daniel Baker, National ResearchCouncil.
Tim Fuller Rowell, Tim.Fuller-Rowell@noaa.gov