The Arctic and Antarctic are the most poorly known regions of the Earth due to their remoteness and harsh environments. Understanding their origin and connection with the global tectonic framework is a fundamental problem of modern earth science. Airborne and satellite magnetic and gravity surveys are principal tools for resolving the polar geology hidden beneath the vast covers of snow, ice and seawater. In the past several years, new satellite geopotential missions are providing opportunities to improve our understanding of the crustal and subcrustal features of polar regions. This work will isolate and model the external, lithospheric, and core magnetic field components in the Orsted and CHAMP satellite mission observations over the Antarctic. Spatially and temporally dynamic components of the external fields will be separated from the static lithospheric and core field components using advanced spectral correlation theory. The lithospheric and core magnetic field components will be further separated using the CHAMP gravity observations. The enhanced lithospheric components will yield new insights on the tectonic properties and evolution of the polar crust. Integrating these satellite components with near-surface geopotential field anomalies will also help reduce ambiguities in geologically interpreting and modeling the anomalies. The enhanced core field components will result in improved models of the polar core field and its secular variations for better definition of crustal anomalies in magnetic survey data. We will also model the CHAMP gravity observations for subcrustal variations in density layers related to thermal plumes and other regions of mass flow that drive polar plate tectonics. Our results will greatly enhance on-going efforts to understand the geological significance of airborne, marine, and terrestrial magnetic surveys by providing crustal and subcrustal interpretations of polar gravity, heat flow, and seismic surveys. The spatial and temporal variations in the extracted polar external field components will also be compared to disturbances in the surface geomagnetic observatory data and electron density distributions of the ionosphere from the GPS data of the Orsted, CHAMP, Ionosonde, and other satellite missions. The analysis will result in improved understanding of the effects of external field variations at the Earth's surface to altitudes of roughly 800 km, the structures and dynamics of magnetospheric-ionospheric coupling, and ionospheric irregularities of the auroral oval that can affect navigation, communications and polar space weather modeling.
This project will also support postdoctoral and graduate student education; foster partnerships with the Istituto Nazionale di Geofisica e Vulcanologia in Rome, Italy, VNIIOkeangeologia in St. Petersburg, Russia, and other international institutions; and lead to the development of new computer codes for modeling regional gravity, magnetic, and thermal effects.
