New insights from satellite magnetic gradient observations into the determination of Earth's lithospheric field

Abstract:

Satellites provide a large stream of data with global coverage and are ideal for deriving global models of the Earth's magnetic field. However, the determination of smaller-scale lithospheric magnetic field features is problematic because the lithospheric signal is contaminated by much larger and highly time-dependent contributions from sources in the ionosphere and magnetosphere. New possibilities open with the three Swarm satellites which provide high quality, simultaneous, measurements from different locations. In addition, North-South and East-West magnetic field gradients can be approximated by employing along-track and across-track field differences which act as high-pass filters of the data and data kernel. We present improvements of conventional lithospheric field modeling approaches to better determine the small-scale lithospheric field by incorporating gradient information.