Regional Spherical Harmonic Magnetic Modeling from Near-surface and Satellite-altitude Crustal Magnetic Anomalies
von Frese, Ralph,R.B.1; Kim, Hyung Rae2; Taylor, Patrick T.3
1The Ohio State Univ., UNITED STATES; 2Kongju Nat. University, KOREA, REPUBLIC OF; 3Planetary Geodynamics Lab,GSFC/NASA, UNITED STATES
The compiled near-surface data and satellite crustal magnetic measured data are modeled with a regionally concentrated spherical harmonic presentation technique over the Antarctic Peninsula and Australia. Global crustal magnetic anomaly studies have used a spherical harmonic analysis to represent the Earth's magnetic crustal field. This global approach, however is best applied where the data are uniformly distributed over the entire Earth. Satellite observations generally meet this requirement, but unequally distributed data cannot be easily adapted in global modeling. Even for the satellite observations, due to the errors spread over the globe, data smoothing is inevitable in the global spherical harmonic presentations. In addition, global high-resolution modeling requires a great number of global spherical harmonic coefficients for the regional presentation of crustal magnetic anomalies, whereas a lesser number of localized spherical coefficients will satisfy. We compared methods in both global and regional approaches and for a case where the errors were propagated outside the region of interest. For observations from the upcoming Swarm constellation, the regional modeling will allow the production of higher resolution local spherical harmonic tensor expansions of the crustal anomaly features that are free from external field effects.