Presentations and Abstracts

Bouman, J. et al.: Swarm magnetic gradients for lithospheric modelling (SLIM). EGU General Assembly, Vienna, April 2016

Bouman, J., J. Ebbing, S. Kotsiaros, M. Brönner, R. Haagmans, M. Fuchs, N. Holzrichter, N. Olsen and E. Baykiev:

Swarm magnetic gradients for lithospheric modelling (SLIM). EGU General Assembly, Vienna, April 2016. View presentation

We present first results of a feasibility study to use magnetic gradient information derived from Swarm data for
crustal field modelling. The study is part of ESA’s Support To Science Element (STSE) Swarm+ Innovations.
In a first step, magnetic gradients have been derived from the observations taken by the three Swarm satellites,
with emphasis on the two side-by-side flying spacecraft. Next, these gradients are used to compute magnetic gradient
grids at 450 km altitude (the present mean altitude of the lower Swarm satellites) for one example region,
North-West Europe. The suggested area comprise both exposed basement geology in southern Sweden and Norway
with crustal scale magnetic anomalies and the Sorgenfrei-Tornquist Zone, a well-studied large scale tectonic
fault system. With sensitivity analysis we studied the added benefit of the information from the gradient grids for
lithospheric magnetic field modelling. A wealth of aeromagnetic data and additional constraining information for
the example area allows us to validate our modelling results in great detail.

Bouman, J. et al.: Swarm magnetic and GOCE gravity gradient grids for lithospheric modelling. ESA Living Planet Symposium, Prague, May 2016

Bouman, J., J. Ebbing, S. Kotsiaros, M. Brönner, J. Sebera., R. Haagmans, M. Fuchs, N. Holzrichter, N. Olsen, E. Baykiev and P. Novak:

Swarm magnetic and GOCE gravity gradient grids for lithospheric modelling. ESA Living Planet Symposium, Prague, May 2016.

We explore how Swarm magnetic gradient and GOCE gravity gradient data can improve modelling of the Earth’s lithosphere and thereby contribute to a better understanding of Earth’s dynamic processes. We study the use of gradient grids to provide improved information about the lithosphere and upper mantle in the well-surveyed North-East Atlantic Margin. In particular, we present the computation of magnetic and gravity gradient grids at satellite altitude (roughly 450 km and 250 km above the Earth for Swarm and GOCE respectively). It is shown that regional solutions based on a tesseroid approach may contain more signal content than global models do. The patchwork of regional grids is presented as well as the subsequent error reduction through iterative downward and upward continuation using the Poisson integral equation. The promises and pitfalls are discussed of using grids at mean satellite altitude.

Bouman, J. et al.: Swarm magnetic and GOCE gravity gradient grids for lithospheric modelling. COSPAR, Istanbul, August 2016

Bouman, J., J. Ebbing, S. Kotsiaros, M. Brönner, J. Sebera., R. Haagmans, M. Fuchs, N. Holzrichter, N. Olsen, E. Baykiev and P. Novak:

Swarm magnetic and GOCE gravity gradient grids for lithospheric modelling. COSPAR, Istanbul, August 2016.

We explore how Swarm magnetic gradient and GOCE gravity gradient data can improve modelling of the Earth’s lithosphere and thereby contribute to a better understanding of Earth’s dynamic processes. We study the use of gradient grids to provide improved information about the lithosphere and upper mantle in the well-surveyed North-East Atlantic Margin. In particular, we present the computation of magnetic and gravity gradient grids at satellite altitude (roughly 450 km and 250 km above the Earth for Swarm and GOCE respectively). It is shown that regional solutions based on a tesseroid approach may contain more signal content than global models do. The patchwork of regional grids is presented as well as the subsequent error reduction through iterative downward and upward continuation using the Poisson integral equation. The promises and pitfalls are discussed of using grids at mean satellite altitude.

Ebbing, J.: With GOCE and Swarm towards the structure of the lithosphere. Invited talk at FSU Jena, November 2015

Ebbing, J. et al.: Pitfalls and possibilities studying the magnetic lithosphere from space. Annual meeting of the German Geophysical Society, Münster, March 2016

Ebbing, J., E. Baykiev and W. Szwillus:

Pitfalls and possibilities studying the magnetic lithosphere from space. Annual meeting of the German Geophysical Society, Münster, March 2016. View poster

Satellite magnetic data have an increasing resolution and their global coverage make them ideal to study the magnetic lithosphere of the Earth. The lithospheric magnetic field is related to the magnetization in the lithosphere and the depth to the magnetic sources itself. The base of the magnetic lithosphere is linked to the Curie temperature, which relates the magnetic lithosphere and the thermal state of the lithosphere. Conventionally, the Moho boundary depth is taken as the maximum magnetic depth and the long-wavelength magnetic field is interpreted to estimate the deepest magnetic sources.

However, the lithospheric magnetic field is derived by removing, at least, a core field contribution, which dominates the long-wavelength signal, which as well relates to the deepest magnetic source. We demonstrate the overlap of long-wavelength signal content by forward modelling the magnetic field from a lithosphere based on gravity, seismological and heat-flow data against data in satellite height.

The model shows that for parts of the world it is reasonable to assume that parts of the upper mantle are magnetized. The large anomalies at satellite height cannot be explained with conventional models of crustal magnetization. However, the impact of core and lithosphere field separation is significant as well. The use of magnetic gradients might help to establish better models of lithosphere magnetization, which in turn allow to update core field contributions. The ongoing Swarm satellite mission will hopefully allow to validate the different field contributions with a higher degree of confidence.