General Information

What is "Space Weather"?

Space Weather can be described as the physical conditions in space that affects human technology in space and on the ground as well as life on Earth in a number of ways including satellite drag, satellite sensor degradation, effects of geomagnetically induced currents on the power grid and pipelines, radiation threat to crews of highflying aircraft and astronauts, high-frequency communication outages in the polar regions (see articles in Song et al., 2001).

Space weather is mainly caused by the Sun because of the variability in its mass and photon emissions on various time scales. The electromagnetic emission consists of the quasi-steady irradiance and flares. While the long-term variability in photon emission may be related to climate effects, the short-term variation (solar flares) affects Earth’s ionosphere resulting in a number of communication problems. The ionization is increased by the flash of enhanced X-ray and EUV emission during flares. The mass emission from the Sun has three components: the ubiquitous solar wind, coronal mass ejections (CMEs), and solar energetic particles (SEPs). CMEs and the solar wind carry the coronal magnetic field into the heliosphere. CMEs propagate into the solar wind and drive shocks; the shocks accelerate SEPs. Flares also accelerate particles, but generally over shorter duration and to lower intensity levels. When CMEs arrive at Earth, they interact with Earth’s magnetosphere causing geomagnetic storms, which have multitude of effects from the magnetosphere to the ground (Gopalswamy, 2009).

An example of the catastrophic consequences of the geomagnetic storms is “The 1989 Quebec Power Outage Event”. On 13 March 1989, a geomagnetic storm affected Canadian and U.S. power systems, resulting in a major power outage for nine hours for the majority of the Quebec region and for parts of the northeastern United States (Molinski et al., 2000). The Hydro-Quebec grid‘s geographic location and its 1,000 km transmission lines to the load center made it susceptible to geomagnetic storms (Kappenman and Albertson, 1990). Central and southern Sweden also experienced power losses when Geomagnetically Induced Currents (GICs) disrupted six 130kV power lines (Babayev et al., 2007). The GICs flowing through the power system severely damaged seven static compensators on the La Grande network in the Hydro-Quebec grid, causing them to trip or shut down automatically before preventive measures were possible (NERC, 1990). The loss of the compensators resulted in a system disturbance and severe equipment damage.

The unavailability of new equipment to replace the La Grande network‘s damaged equipment prevented power restoration to the transmission network. The power delay was also due to the damaged equipment and load transfers at the distribution network level. While work was being conducted to bring power back to the Hydro-Quebec grid, the New Brunswick and Ontario power systems helped provide emergency assistance to Quebec. As power was restored to Hydro-Quebec, it received assistance from New England and New York systems as well as the Alcan and McLaren systems based in Quebec. The voluntary reduction of power use by industrial customers during the incident also helped Quebec to meet its power demands.

After nine hours, 83% of full power was restored but one million customers were still without electrical power (NERC, 1990). The total cost of the Hydro-Quebec incidents is estimated to be $6 billion. (Canada/OCIPEP, 2002). Since the incident, the Canadian government has set up protective measures at the Hydro-Quebec site, such as transmission line series capacitors, which cost more than $1.2 billion, to block GICs from damaging the system (Canada/OCIPEP, 2002).

As it is obvious, it is very important to be able to predict the geomagnetic consequences by the arrival of an event which could produce such results. For that reason Athens Space Weather Forecasting Center (ASWFC) provides in a daily basis a Space Weather Report giving a prediction of Ap geomagnetic index and as a result an estimation on the levels of the potential geomagnetic storms.