Topic: "Using GPS to Study Earth's Ionosphere and Magnetosphere" (Video)
Abstract: Most of us know GPS as a means to track locations and times of events on Earth, and for such applications, ionospheric and magnetospheric effects are error sources that must be eliminated. However, for space physicists, the situation is reversed: the very effects that disrupt ground-based applications of GPS present dramatic new ways to observe the space environment. In the last decade, total electron content (TEC) maps derived from the global set of GPS data have provided a paradigm shift in the ways that Earth's ionosphere and magnetosphere are observed. Prior to GPS, most scientific measurements of the magnetosphere-ionosphere were from individual observing sites or systems providing information about a region or a single point. With GPS, by combining individual measurements from multiple receivers, high resolution temporal and spatial information is available on a global scale. After a review of GPS fundamentals, including an explanation of how GPS is used to measure properties of the atmosphere and a brief history of ionospheric measurements with GPS, this talk will describe aspects of large-scale geomagnetic storms observed for the first time using TEC maps derived from GPS data. The new methods allow observations of conjugate features of the large-scale storms (in both the Northern and Southern Hemisphere), as well as correlation of these features with large-scale drainage plumes of plasma escaping from the high density inner part of Earth's magnetosphere during the storms. Combining GPS data with radar and magnetometer data from extensive networks of observatories provides a big picture view of geomagnetic storms and their impact on the upper atmospheric regions.