Space Weather Research Presented at the 2007 AGU Fall Meeting

AGU's 47th annual Fall Meeting, held 10–14 December 2007 in San Francisco, Calif., was the largest gathering of geoscientists in the Union's history. More than 14,600 people attended. The Space Physics and Aeronomy (SPA) sections sported excellent turnout, with more than 1300 abstracts submitted over 114 poster and oral sessions. Topics discussed that related to space weather were manifold: the nature of the Sun-Earth system revealed through newly launched satellites, observations and models of ionospheric convection, advances in the understanding of radiation belt physics, Sun-Earth coupling via energetic coupling, data management and archiving into virtual observatories, and the applications of all this research to space weather forecasting and prediction. One highlight of the “space weather” aspects of the meeting was SPA's contribution to AGU's Bowie lecture series. The Bowie lectures, inaugurated in 1989 to commemorate the 50th presentation of the William Bowie Medal (AGU's highest honor, named for AGU's first president), represent the finest research as determined by individual AGU sections. SPA presented the Nicolet Lecture, given by Robert R. Meier. Meier, a research professor of space science at George Mason University's Department of Physics and Astronomy (Fairfax, Va.) and a noted space weather scientist, spoke on the possibility of understanding Sun-Earth coupling through innovative imaging techniques. His talk, “Geospace Imaging: The Big Picture,” examined advances made in the 50-year history of satellite launches. He predicted that the research field will soon be able to trace via images the paths of radiation and plasma eruptions from their origin on the Sun through the magnetosphere, plasmasphere, ionosphere, and thermosphere. “Images can yield superb quantitative information,” Meier said. “They are not just pretty pictures.” Two groups of sessions at the Fall Meeting directly concerned space weather. In the group titled “The Equatorial Ionosphere During Quiet and Perturbed Times: Recent Progress and Applications to Space Weather,” speakers commented on observations and simulations of recent geomagnetic storms, including events that occurred in December 2006, November 2004, and July 2000. J.D. Huba of the Naval Research Laboratory (NRL, Washington, D. C.) discussed two new NRL models that simulate the equatorial spread F (ESF), a low-latitude ionospheric phenomenon that leads to the development of large-scale electron density depletions that can significantly disturb communications and navigation systems. B.G. Fejer (Utah State University, Logan) discussed how satellite studies that compare ESF during geomagnetically quiet and disturbed times illustrate the strong longitudinal variations of the equatorial evening and nighttime drifts and their dependence on seasonal variations in ionospheric conductivity. An upgrade of instrumentation at a research facility in Sao Luis, Brazil, also enables scientists to better construct radar images of equatorial ionospheric scattering structures and ESF, according to a talk presented by F.S. Rodriques (Cornell University, Ithaca, N. Y.). R.L. Bishop (The Aerospace Corporation, El Segundo, Calif.) reviewed how recent observational and modeling work links low-latitude ionospheric scintillation, which can disrupt satellite signals, with convective tropospheric storms. Other talks in this group of sessions discussed efforts to model equatorial ionospheric bubbles by the Air Force Research Laboratory in preparation for their Communication/Navigation Outage Forecasting System (C/NOFS) mission. These bubbles are thought to be associated with scintillation (see M.C. Kelley et al., Convective ionospheric storms: A major space weather problem, Space Weather Quarterly, 3(2), 8–13). The second group of sessions that directly involved space weather was “Advances in Space Weather Modeling and Forecasting Techniques.” M. Gehmeyer (University of Colorado, Boulder) discussed three forecast models developed by the National Science Foundation's Center for Integrated Space Weather Modeling (CISM) Science and Technology Center, showing their utility in supporting missions soon after launch, interpreting satellite data, and developing new insights into aurorae. Another talk, presented by A.A. Ridley (University of Michigan, Ann Arbor), described data processing and validation issues surrounding the Space Weather Re-analysis project, which seeks to create a data-driven complete picture of the geospace environment over a whole solar cycle for use in practical applications. Similarly, M. Hesse (NASA Goddard Space Flight Center, Greenbelt, Md.) described products, capabilities, and future efforts of the Community Coordinated Modeling Center (CCMC), a U.S. interagency program that facilitates research in support of the generation of advanced space weather models. CCMC models are available for public use. Discussion at these space weather–focused sessions involved how stronger collaborations are needed between the research community and the operations community in developing methods by which complex models can be validated and ultimately used to issue alerts. Speakers stressed that operators need to better understand models so that they can more easily make operational decisions about space weather and, when necessary, issue space weather warnings. The AGU Fall Meeting also featured talks on how to manage the vast amount of data generated by programs that monitor the Sun-Earth environment from the ground and space and by the models that support space weather prediction. Several scientists presented information about capabilities and future directions of the virtual Heliophysics Great Observatory, a data archiving system that support NASA's fleet of spacecraft that have heliophysics research goals. Others discussed the National Solar Observatory's Virtual Solar Observatory, a software system that links together distributed archives of solar data along with data search and analysis tools. Attendees stressed that because adverse space weather is a global problem, common nomenclature must be standardized internationally to help with issuing alerts. Beyond space weather operations, several sessions highlighted significant research advances. Many talks focused on new discoveries about aurorae as seen from the five probes composing the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission. Launched in February 2007, THEMIS observed substorms, which are energy releases from the Earth's magnetosphere that intensify aurorae. Several speakers discussed how THEMIS has revealed new insight into the dynamics of rapidly developing substorms. In particular, meeting participants discussed a substorm that erupted on 23 March 2007 over Alaska and Canada that produced vivid aurorae for more than 2 hours. These aurorae were observed to surge westward about twice as fast as any westward surges previously measured, and more than anyone thought possible, crossing 400 miles in less than 1 minute; the entire 2-hour event produced a total energy equivalent to a 5.5-magnitude earthquake. By observing this substorm, THEMIS satellites have found evidence that magnetic flux ropes appear to connect the Earth's upper atmosphere directly to the Sun. Meeting attendees described how solar wind particles might flow along these ropes, fueling geomagnetic storms and substorms. Another broad group of presentations focused on space weather hazards specifically relating to satellites and probes. One session considered the energetic particle fluxes and intense electric fields in the vicinity of geosynchronous orbit where many commercial and national security satellites operate. Other scientists considered space hazards beyond Earth; effects from the December 2006 solar flares were seen by the Venus Express and Mars Express, prompting conference attendees to discuss operational considerations for probes to withstand adverse space weather events. The need for space weather awareness in primary school education programs was also recognized at the meeting. A session in AGU's Education section described the Space Weather Around the World Program, which uses NASA satellite data and educational resources to provide a framework for primary school students and teachers to study the effects of solar storms on Earth. More information on these and other presentations and posters at the Fall Meeting, including conference abstracts, can be found at http://www.agu.org/meetings/fm07/. Mohi Kumar is a staff writer for the American Geophysical Union.

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