An integral component of the multi-agency U.S. Global Change Research Program (Our Changing Planet," Committee on Earth Sciences, 1991) is understanding and modeling the geospace environment. As part of its contribution to the U.S. Global Change Research Program, the National Science Foundation's Division of Atmospheric Sciences has established a new research initiative, Geospace Environment Modeling (GEM), with the goal of supporting basic research into the dynamical and structural properties of geospace, leading to the construction of a global geospace model with predictive capability. The subjects of the first GEM campaign are the magnetospheric boundary, the magnetosheath beyond it, and the connection from the boundary through the magnetosphere to the ionosphere. This grant is designed to integrate on-going measurements of magnetic field fluctuations at conjugate locations (Iqaluit, Canada, and South Pole, Antarctica) at high geomagnetic latitudes with other measurements to be carried out under the GEM Program in order to obtain a more "global" description of the dayside magnetopause environment. Of particular interest will be the study on a "global" scale of magnetic impulse events, which appear to delineate regions of localized magnetic field-aligned currents.
