When most people hear the words "weather forecast", they expect to hear something about clouds, rain, snow or winds.
But now, Canadian scientists are working to provide another kind of forecast—a space weather forecast that will predict turbulent events in the highest reaches of the Earth's atmosphere where it meets a flood of electromagnetic radiation and electrically charged particles.
The solar radiation and particles interact in complex ways with both the upper atmosphere and the Earth's magnetic field, causing a range of effects including the auroras and space storms that can damage satellites and spacecraft, disrupt communications around the world and overload power networks on the ground.
Events like these make this vast and often tumultuous area of geospace of great economic as well as scientific importance. "There are billions dollars of space assets in that region of space," said John Manuel, a program scientist with the Canadian Space Agency (CSA), one of the agencies funding the effort to improve forecasting of space weather. "When the weather there is rough, those assets can be damaged and sometimes destroyed."
In 1989, a space storm knocked out Hydro Quebec's electrical grid, causing a nine-hour blackout and multi-million-dollar losses. In 1994, two Canadian communications satellites, Anik E-1 and E-2, were disabled by space storms at a cost of hundreds of millions of dollars. Many other satellites have malfunc-tioned, interrupting media services and cell phone and GPS navigation systems.
Manuel noted that high-flying aircraft, especially those that follow polar routes, are also affected by space weather and the higher levels of radiation it can create. "There are an increasing number of flights across the North Pole and those regions are less protected from disturbances in space," said Manuel.
The CSA is working with Natural Resources Canada to improve the prediction of space weather events. "Just as we have a meteorology service that monitors the weather and climate to make forecasts so that people can prepare themselves for whatever's coming, we have the beginnings of a space weather forecast service on the way." Natural Resources Canada has set up Space Weather Canada as a regional warning centre of the International Space Environment Service.
The ability to predict space weather events depends on the travel time between the sun and Earth. Solar radiation reaches Earth in just a few minutes, and some charged particles also arrive quickly, but others can take several days. A coronal mass ejection, for example, is "slower moving," said Manuel. "These are blasts of billions of tonnes of ionized gas ejected by the sun during active periods. If the Earth is in the way of one of those, it can cause massive disturbances in the magnetic field. They take a few days to arrive, so if we know they're coming, space weather forecasters can issue warnings to airlines, satellite operators and hydroelectric operators so they can prepare themselves."
There are things these industries can do to reduce their vulnerability. Airlines can divert or cancel flights and power companies can make adjustments to their electricity grids. Satellite operators can put their spacecraft into low-power safe modes and shut down critical or vulnerable components.
Manuel said Canada is in a unique position to study space weather because it is the country with the largest landmass beneath the auroras and geomagnetic disturbances in the ionosphere, the region at the top of the atmosphere containing electrically charged particles where the auroras are located. "By virtue of its location, Canada has a front-row seat. The auroras are shifted further south over Canada than any other country and this makes it easy for us to put arrays of instruments underneath them."
For many years, Canada has used this geographic advantage to study solar-terrestrial interactions in the ionosphere and has become a world leader in this field. Now it is enhancing this infrastructure with new instruments deployed in new ways, creating an even more extensive system for monitoring and studying geospace. This system, called Canadian Geospace Monitoring (CGSM), is operated by Canadian universi-ties and government laboratories, each contributing their expertise to the system. The result is in many ways more than the sum of these individual contributions and includes state-of-the art instruments and facilities:
All-Sky Imagers: The University of Calgary operates 13 digital cameras that image the aurora across much of northern Canada at different wavelengths (colours) of light. These colours are the result of charged particles from space colliding with atoms in the upper atmosphere, so observing them provides important information about the regions of space where they come from and the physical processes that cause the aurora.
Meridian-Scanning Photometers: The University of Calgary operates four of these instruments to observe very dim aurora that cannot be captured by the imagers. These measurements provide unparalleled information about dynamic processes that cause space storms and affect the upper atmosphere in dramatic ways. Together, the imagers and photometers provide a wealth of data for auroral scientists, and are increasingly used to understand space weather and its effects on our atmosphere.
Riometers: The University of Calgary and Natural Resources Canada operate more than 30 of these radio instruments that observe the radio emissions of the cosmic background radiation. Dis-turbances in the ionosphere caused by high-energy particles from space disrupt these radio emissions. Canadian researchers have become world leaders at using the riometer data to under-stand how particles from space affect geospace and our atmosphere.
Ionosondes: The University of New Brunswick operates six of these instruments that send out bursts of radio energy high into the atmosphere. These operate like small radars, and the echoes returned provide a wealth of information about important properties of our upper atmosphere. Canadian ionosondes provide one of the world's only ways of tracking space weather effects on the electrical properties of the upper atmosphere.
Global Positioning System (GPS) Receivers: The University of New Brunswick operates nine of these instruments that observe GPS signals transmitted by navigation satellites. Disturbances in the upper atmosphere disrupt the signals and reveal the locations of ionized plumes that interfere with radio communication and navigation.
High Frequency (HF) Radars: The University of Saskatchewan operates four of these radars. They send out bursts of radio energy and measure the reflections from moving disturbances in the ionosphere. Unlike the ionosondes, which usually look straight up, the HF radar signals go out at a more horizontal or oblique angle. These radars can be used to detect horizontal movements of electrically charged gases in the ionosphere, caused by heating from the aurora, and are used to create maps of ionospheric winds over much of Canada.
Flux Gate Magnetometers: The University of Alberta and Natural Resources Canada operate more than 30 of these instruments that measure the strength of the Earth's magnetic field in their vicinity with great precision. Magnetic fields and electrical currents are inextricably linked. The ionosphere is awash in electrical currents caused by solar-terrestrial interactions and these cur-rents affect the Earth's magnetosphere; measuring magnetic field strength on Earth can reveal important information about the state of the electrical currents high in the ionosphere.
Induction Coil Magnetometers: The University of Alberta operates seven of these instruments which detect very fast variations in the Earth's magnetic field and complement the flux gate mag-netometers. These magnetic waves are used to study physical processes associated with the aurora, solar wind, and space storms.
Solar Radio Flux Monitor: The National Research Council operates this radio antenna to moni-tor the Sun’s activity and has done so every day for more than 60 years. Variations in the intensity of this radiation are correlated with the number of sunspots on the sun. Sunspots are relatively dark areas on the sun associated with intense magnetic activity. This project has created an unparalleled record of solar variability which is important for space weather, studies of climate change, and for tracking the origin at the sun of the disturbances that the CGSM system was created to study.
Computer Simulations: The Universities of Alberta and Waterloo both run computer modeling and simulation projects that are designed to explore how geospace works and how the sun affects our near-Earth space environment. These projects use the data from the CGSM instruments and sophisticated computer models to test ideas about physical the processes that govern near-Earth space. A long-term goal of the CGSM program is to deepen understanding of geospace to the point of being able to make detailed and accurate space weather forecasts.
"Our understanding of how geospace works is still rudimentary, not much better than our understanding of weather on Earth a century ago," said Manuel. He noted that accurate weather forecasting became possible only when satellites could look down on the Earth and see entire weather systems. "The CGSM system is poised to do the same for space weather by making it possible to remote-sense space far above Canada in the same way that weather satellites currently remote-sense our atmosphere."