Modern society depends strongly on the satellite based communication and global navigation systems. Collectively, these systems are called Global Navigation Satellite Systems—or GNSS. While having their origin in the military systems for Positioning, Navigation and Timing—PNT from the 1970’s, the technology is now spread throughout society for commerce, communications, travel and first response to natural disasters including hurricanes like the recent storm over New York and New Jersey named Sandy. From daily personal communications, to ordinary daily business transactions, to national defense, these communication and navigation systems underlie modern society.

The systems while robust could be disrupted by what are known as geomagnetic storms. In contrasts to the severe weather storms originating from seasonal changes in the thin 10 km thick layer known as the troposphere, the geomagnetic storms arise from eruptions of high temperature hydrogen gas on the surface of the sun. The eruptions are called coronal mass ejections or CMEs. The CMEs are frequent, take typically three days to reach the radius defined by the orbit of the Earth around the sun, and have a relatively small probability of hitting the Earth. However, occassionally CMEs containing tons of material traveling at supersonic speeds with Mach numbers of 5-10 do pass over the Earth’s magnetosphere. When this occurs there are mega amperes of currents and voltages induced in the ionosphere as shown in Fig.1 as I1, I2 and the eastward electron jet EEJ. Trapped electrons and protons in the Earth’s magnetic field are accelerated to high energies during the storm The electron energies become relativistic and are commonly referred to as “killer electrons” owing to their destroying spacecraft electronics. Smaller versions of the transient electric discharges are familiar to those living in the northern latitudes as the aurora or “the northern lights”. The aurora light occurs as the electric currents enter the region of the atmosphere in the altitude range from 90 km to 120 km. This region forms the electrically conducting shell shown in Fig. 1 due to the ionization of the gasses, principally NO and atomic oxygen O, at these altitudes by UV solar radiation. This is the same radiation giving us the severe sun burns. At the surface of the Earth, however, this UV radiation is highly attenuated from the ionization processes that create the ionosphere.

A thoroughly researched example of a severe solar magnetic storm in recent times is the March 1989 solar storm hitting Quebec, Canada and bordering areas of the United States. The Quebec storm caused electrical blackouts and disrupted communication for days. The economic damage equivalent to major hurricanes is described in a NOAA-Department of Commerce publication. Other strong storms receiving detailed study by scientists around the world are the Bastille Day Storm of July 14 in 2000 and the Halloween Storm of 23-30 Oct 2003. These storms have pushed the US to form an extensive research and development program for monitoring solar activity and attempting to predict the probability of a particular solar eruption of causing damage to the power distribution and communications systems. The field is known as Space Weather. Just as with troposphere weather, the science involves a combination of real-time data acquisition, fast processing of the data and using the best simulation models to predict probabilities for different outcomes. Just as with Hurricanes—called Typhoons in Asia—the forecasted outcome is updated as the disturbances become better defined approaching the Earth. Appropriate alerts are issued to a wide community including airline flights, GNSS providers, military and first responders for medical and social emergency services.

The author has developed a real-time model that takes data every minute from a solar observing satellite called ACE that is positioned in between the Earth and sun at the point where the pull of gravity from the Earth is balanced by the pull of gravity from the sun. This position is one of the famous equilibrium points found by Lagrange in 1772 called the L1 point. Here the ACE and other spacecraft hover for years with only solar power to remain fixed in space.

Solar wind and plasma data are downloaded by radio frequency signals and fed to computers that run the physics models at the Community Coordinated Website at the Goddard Space Flight Center [http://ccmc.gsfc.nasa.gov]. Going to the Instant Run Tab on the menu one finds the WINDMI model which takes ACE spacecraft data and makes a one hour prediction for the level of the approaching storm. Minor disturbances lasting a few hours are called substorms and major storms lasting days are the ones causing emergencies and large economic losses.

Currently, the author is working with scientists in Europe at the Aix-Marseille University developing new models for space weather. The author says that we are now focused on developing predictions for the disruptions in the high frequency radio signals used in the GNSS and GPS systems for positioning, navigation and timing. These are the critical elements for security and the economy in planning for future 100-year solar storms. While the economic losses from Hurricane Sandy are estimated at 80 billion dollars and Katrina estimated at 120 billion dollars, we note that the New York Times and the International Herald Tribune1 of 3 November ran the Editorial Opinion article titled “Solar Sandy”. The article describes horrific economic losses as well as social disorder and chaos that could follow the collapse of the wireless communication and navigation systems that our society now uses every moment of the day for all types of transactions and communications. The NYT article calls for building up the inventory of 400 kilo-Volt, other high voltage transformers that distribute power through society. With extended loss of electric power and communications the article estimates the economic losses would be in the trillions of dollars.

While such estimates are far from exact, the science that underlies the understanding the physics and engineering is exact and very exciting. The science combines plasma physics, electrical engineering and computer science in a collage of forefront research.

References

1. “Not Ready for a ‘Solar Sandy’, Yousaf Butt”, New York Times Nov 2, 2012 and Editorial Opinion p.6 Saturday-Sunday, International Herald Tribune.

Weather Events—Understanding Societal and Economic Impacts: A Workshop Report, The National Academies Press, Washington, D.C., 2008.

Jana Goldman, Solar Storms cause significant economic and other impacts on earth, April 5, 2004, http://www.magazine.noaa.gov/stories/mag131.htm