A High-Order Model of the Earth's External and Induced Magnetic Field

For centuries people have used magnetic compasses to guide them on their way and explore new territories. This has led scientists to embark on their own journeys of discovery about Earth's magnetism, and to the discovery of electromagnetism that is at the heart of modern technology - phones, TVs, computers, etc. Now, in the age of GPS, you might think that compasses are obsolete, but guidance by the Earth's magnetic field is still vital to explore for oil and minerals below ground (where GPS can't reach) and as a safety backup for planes, etc. And, ironically, GPS is affected by natural hazards caused by the Earth's magnetic field.
So the scientific study of Earth's magnetism continues to be important in many ways, so much so that in 2012 the European Space Agency will launch a mission called Swarm in which three satellites will orbit the Earth to survey its magnetic field in unprecedented detail. These measurements will be used to improve mathematical models of the geomagnetic field that provide a standard reference for various applications. One target area is a better understanding and description of the relatively rapid and complex magnetic fluctuations caused by electrical currents flowing in the upper atmosphere and in Space, ultimately driven by disturbances happening on the Sun that wax and wane with an 11-year solar cycle. This so-called external magnetic field also induces currents to flow in oceans and under the Earth's surface which in turn creates additional magnetic fluctuations.
Together, the external and induced magnetic field (EIMF) limits the accuracy of geomagnetic field models such that they aren't useful for surveys and navigation at places and times when the EIMF fluctuations are large, such as in the polar regions and during so-called magnetic storms that may happen once a month and last several days. The EIMF also creates a natural hazard for large-scale electrically conducting systems such as power outages in electricity grids, corrosion in oil pipelines, and even phantom railway signals.
In this project we will study the EIMF using a solar cycle's worth of measurements made at over 300 different locations around the world, recently collected together for the first time by an international project called SuperMAG. Our idea is to borrow mathematical techniques usually used by meteorologists for studying the weather and climate to identify the natural cycles and patterns of the EIMF. In conjunction with the Swarm mission, the resulting new descriptions and understanding of the EIMF "weather" and "climate" should help to improve the next generation of computer models of Earth's magnetic field. It can also be used to as a basis to assess and predict the risk of power outages in UK's National Grid caused by extreme EIMF fluctuations.

The main beneficiaries of our research will be the following:
a. Surveyors of natural resources. Surveys to explore for natural underground resources use models of the geomagnetic field to guide their equipment. These models neglect most of the EIMF, which means that they are unsuitable for surveying during geomagnetically active times and in the polar regions. Thus geomagnetic field modellers are interested in ways to better represent the EIMF in their models for such stakeholders (see letter of interest from Prof Nils Olsen, author of the Comprehensive Model of the geomagnetic field). In addition, information on past EIMF variability and its controlling factors can help the exploration industry manage the risks of disruption to their surveys.
b. Electricity supply network managers. Rapid external magnetic field variations cause Geomagnetically Induced Currents (GIC) to flow in high voltage power grids, in polar, mid and low latitude power systems. Uncertainty in our understanding of GIC gives rise to large risks, with the UK government concluding that the potential impact of severe such space weather on the national infrastructure is "one of the highest priority risk areas" [H.M. Government, 2010]. There is thus an interest from electricity supply network managers in knowledge and models of GICs that they can use to develop strategies to manage the risk.
c. Society. Scientific discovery and knowledge enriches society through its inspiration and education. BAS attracts a particularly high media profile with 3,625 individual news items (in the English language) during 2009, providing over half a billion people with the opportunity to see/hear/read about BAS in the UK and at least 65 other countries. 70% of these were generated pro-actively from 16 press releases mostly (13) based on peer-reviewed science publications. Lancaster University provides a service called AuroraWatch to over 48,000 people, providing them with email messages, tweets and Facebook updates alerting them to the possibility of seeing the aurora in the UK, based on real-time data from SAMNET magnetometers. Lancaster University also provides undergraduate education in space weather and runs educational activities for the local community. All these will contribute to raising public awareness of geomagnetism and its space weather effects.
d. Local industry. BAS has developed a special low power magnetometer (LPM) system suitable for remote environments based on solar and wind power, and innovative instrument and data management. The power supply technology is also now being used to run other instruments such as GPSs, meteorological stations, and remote cameras. Besides the 11 BAS LPMs, BAS has also made 12 other LPMs under contract to China, Italy and Japan (4 each). Fabrication has now been spun-off to a local company who have to date delivered the Chinese contract and several other power systems, generating over £20k income to NERC. As part of this proposal, BAS will develop a real-time communications capability for the LPMs.