Fifth‐generation lithospheric magnetic field model from CHAMP satellite measurements

Abstract

[1] Six years of low-orbit CHAMP satellite magnetic measurements have provided an exceptionally highquality data resource for lithospheric magnetic field modeling and interpretation. Here we describe the fifth-generation satellite-only magnetic field model MF5. The model extends to spherical harmonic degree 100. As a result of careful data selection, extensive corrections, filtering, and line leveling, the model has low noise levels, even if evaluated at the Earth's surface. The model is particularly suited for inferring large-scale structure and composition of the lithosphere. It is also meant to serve as the long-wavelength part of continental-and global-scale marine and aeromagnetic anomaly maps.

Near-Earth magnetic signature of magnetospheric substorms and an improved substorm current model

“…possible by subtracting a recent crustal magnetic field model, MF5 (Maus et al, 2007), from the magnetic vector data.…”

Use of the Comprehensive Inversion method for Swarm satellite data analysis

“…In addition, several issues surrounding SIVW should be explored, such as the optimal SH order m that delineates between the nominal and nuisance lithospheric fields, which could easily lead to better models. In addition, SIVW could be used to account for dayside bias when modeling the lithosphere, which would reflect the current best methods for crustal field modeling (Thomson and Lesur, 2007;Maus et al, 2007Maus et al, , 2008Lesur et al, 2008Lesur et al, , 2013Olsen et al, 2011). Finally, SIVW could be applied to high degree SV modeling by mitigating the bias due to the poor distribution of ground observatories.…”

“…Different philosophies exist on how to enhance the recovery of signals of interest, like the lithosphere, while mitigating the effects of unwanted or contaminating signals in the estimation procedure. Several recent models have employed direct data selection techniques to derive good descriptions of core and crustal fields (Maus et al, 2007(Maus et al, , 2008Thomson and Lesur, 2007;Lesur et al, 2008;Olsen et al, 2011). The "Comprehensive Modelling" (CM) approach (Sabaka et al, 2002(Sabaka et al, , 2004 has not generally relied upon this practice, with the exception of gross outliers, etc., but rather has focused on using as much data as possible to ensure a stable co-estimation of parameters from all sources.…”

Long-wavelength magnetic anomalies as a guide to the deep crustal composition and structure of eastern Australia

“…Data that were available for review comprised the Geoscience Australia Magnetic Map of Australia grid, fifth edition (Milligan et al, 2010), the AWAGS-2 line magnetic data, the AusMoho model of depth of the Mohorovičić Discontinuity (Kennett et al, 2011), a Curie depth model for Australia (Maule et al, 2009) based on the Maus et al (2007) global crustal magnetic field model, and upper mantle V p from an ongoing teleseismic study (Musgrave & Rawlinson, 2010;Fishwick & Rawlinson, 2012).…”

“…The AWAGS tielines were collected in two phases: AWAGS-1, which comprised a set of flights linking ground magnetic base-stations (Milligan et al, 2004), and AWAGS-2, a rectangular grid of tie-lines at 75-km spacing (Minty, 2011). GA revised their national composite TMI grid to incorporate the AWAGS control, and added an additional constraint on very-long wavelengths (>1000 km) from satellite magnetic data from the CHAMP program (Maus et al, 2007). Substantial differences are visible between maps derived from the pre-AWAGS and post-AWAG-1 grids; subsequent revisions of the grid following AWAGS-2 and the addition of further local surveys produced little change to the longwavelength components.…”