GEM Systems Science: Creating and Analyzing an Earth Index Collection

Space Science Institute, Boulder CO

Investigators

Abstract

The Geospace Environment Modeling (GEM) Program is a broad-based, community-initiated research program on the physics of the Earth's magnetosphere and the coupling of the magnetosphere to the atmosphere and to the solar wind. The work of GEM is accomplished in a series of campaigns and focus groups that solve specific problems leading to the construction of a global Geospace General Circulation Model (GGCM) with predictive capability. This project will contribute essential results to this goal pertaining to understanding the global reaction of the Earth's magnetosphere-ionosphere system to the solar wind and how the solar wind couples to the magnetosphere. The reaction of the magnetosphere to driving as well as the driving by the solar wind are more complex than commonly thought and than current models can capture or explain. This Investigation will perform a comprehensive statistical analysis to explore those complexities. The data sets created and the findings of the analysis will be disseminated via a new "Earth Index Collection" webpage to be created. Tutorials, examples, and research suggestions will also be made available via the webpage. This Investigation will take a systems-science approach, analyzing the reaction of the multiply measured magnetosphere to the full solar-wind data set. It will collect and create a large number of time-dependent indices, each one being a different measure of the magnetosphere-ionosphere system. The "indices" will be measures of the currents, plasmas, energetic particles, waves, morphology, and energy flow in the system. The collection of time-dependent indices will be put together to form a time-dependent "Earth Index Collection" of measurements. Canonical correlation analysis will be used to identify and explore correlation patterns between the multivariable Earth index collection and the multivariable solar-wind data set. For the primary mode of reaction of the Earth index collection to the solar wind, a time-dependent "collective index" will be identified and defined and the universal coupling function that drives that primary mode will be defined. Secondary global modes of the reaction of the Earth to the solar wind will be identified, cataloged, and investigated and the properties of the solar wind (the secondary coupling functions) that drive the secondary modes will be identified. Attempts will be made to connect the secondary coupling functions with physical mechanisms such as the viscous interaction, changes in the location of the dayside reconnection line, and changes in the morphology of the magnetosphere. By analysis of the secondary modes of reaction, the "sectors" of the Earth index collection will be identified and the indices that comprise each sector will be cataloged. Exploring suppression and confounding in the multivariable solar-wind data set as its variables correlate with the Earth measurements, causal correlations versus non-causal correlations will be identified. Finally, traditional data-analysis methods will be used to elucidate the sectors and the global modes of reaction of the magnetosphere to the solar wind.